DS-25PE20–139C–8/2018
Features
Single 1.65V - 3.6V supply
Serial Peripheral Interface (SPI) compatible
Supports SPI modes 0 and 3
Supports RapidS
™
operation
Continuous read capability through entire array
Up to 85MHz
Low-power read option up to 15MHz
Clock-to-output time (t
V
) of 6ns maximum
User configurable page size
256 bytes per page (default)
264 bytes per page (customer selectable option)
One SRAM data buffer (256/264 bytes)
Flexible programming options
Byte/Page Program (1 to 256/264 bytes) directly into main memory
Buffer Write
Buffer to Main Memory Page Program
Single Command Page Read-Modify-Write Option
Flexible erase options
Page Erase (256/264 bytes)
Block Erase (2KB)
Sector Erase (32KB)
Chip Erase (2-Mbits)
128-byte Security Register
128 bytes factory programmed with a unique identifier
Hardware and software controlled reset options
JEDEC Standard Manufacturer and Device ID Read
Low-power dissipation
300nA Ultra-Deep Power-Down current (typical)
5µA Deep Power-Down current (typical)
25µA Standby current (typical)
7mA Active Read current (typical)
Endurance: 100,000 program/erase cycles per page minimum
Data retention: 20 years
Complies with full industrial temperature range
Green (Pb/Halide-free/RoHS compliant) packaging options
8-lead SOIC (0.150ʺ wide and 0.208" wide)
8-pad Ultra-thin DFN (5 x 6 x 0.6mm)
AT25PE20
2-Mbit DataFlash-L
Page Erase Serial Flash Memory
DATASHEET
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Description
The Adesto
®
AT25PE20 is a 1.65V minimum, serial-interface sequential access Flash memory is ideally suited for a wide
variety of digital voice, image, program code, and data storage applications. The AT25PE20 also supports the RapidS
serial interface for applications requiring very high speed operation. Its 2,162,688 bits of memory are organized as 1,024
pages of 256 bytes (default) or 264 bytes (customer option) each. In addition to the main memory, AT25PE20 also
contains one SRAM buffer of 256/264 bytes. The Buffer can be used as additional system scratch memory, and E
2
PROM
emulation
(bit or byte alterability) can be easily handled with a self-contained three step read-modify-write operation.
Unlike conventional Flash memories that are accessed randomly with multiple address lines and a parallel interface, the
Adesto DataFlash-L
®
uses a serial interface to sequentially access its data. The simple sequential access dramatically
reduces active pin count, facilitates simplified hardware layout, increases system reliability, minimizes switching noise,
and reduces package size. The device is optimized for use in many commercial and industrial applications where
high-density, low-pin count, low-voltage, and low-power are essential.
To allow for simple in-system re-programmability, AT25PE20 does not require high input voltages for programming. The
device operates from a single 1.65V to 3.6V power supply for the erase and program and read operations. The
AT25PE20 is enabled through the Chip Select pin (CS) and accessed via a 3-wire interface consisting of the Serial Input
(SI), Serial Output (SO), and the Serial Clock (SCK).
All programming and erase cycles are self-timed.
1. Pin Configurations and Pinouts
Figure 1-1. Pinouts
Note: 1. The metal pad on the bottom of the UDFN package is not internally connected to a voltage potential.
This pad can be a “no connect” or connected to GND.
1
2
3
4
8
7
6
5
CS
SO
WP
GND
Vcc
RESET
SCK
SI
8-lead SOIC
Top View
CS
SO
WP
GND
Vcc
RESET
SCK
SI
8
7
6
5
1
2
3
4
8-pad UDFN
Top View
(through package)
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Table 1-1. Pin Configurations
Symbol Name and Function
Asserted
State Type
CS
Chip Select: Asserting the CS pin selects the device. When the CS pin is deasserted, the
device will be deselected and normally be placed in the standby mode (not Deep Power-Down
mode) and the output pin (SO) will be in a high-impedance state. When the device is
deselected, data will not be accepted on the input pin (SI).
A high-to-low transition on the CS pin is required to start an operation and a low-to-high
transition is required to end an operation. When ending an internally self-timed operation such
as a program or erase cycle, the device will not enter the standby mode until the completion of
the operation.
Low Input
SCK
Serial Clock: This pin is used to provide a clock to the device and is used to control the flow of
data to and from the device. Command, address, and input data present on the SI pin is
always latched on the rising edge of SCK, while output data on the SO pin is always clocked
out on the falling edge of SCK.
— Input
SI
Serial Input: The SI pin is used to shift data into the device. The SI pin is used for all data input
including command and address sequences. Data on the SI pin is always latched on the rising
edge of SCK. Data present on the SI pin will be ignored whenever the device is deselected (CS
is deasserted).
— Input
SO
Serial Output: The SO pin is used to shift data out from the device. Data on the SO pin is
always clocked out on the falling edge of SCK. The SO pin will be in a high-impedance state
whenever the device is deselected (CS is deasserted).
— Output
WP
Write Protect: When the WP pin is asserted, all sectors specified for protection by the Sector
Protection Register will be protected against program and erase operations regardless of
whether the Enable Sector Protection command has been issued or not. The WP pin functions
independently of the software controlled protection method. After the WP pin goes low, the
contents of the Sector Protection Register cannot be modified.
If a program or erase command is issued to the device while the WP pin is asserted, the device
will simply ignore the command and perform no operation. The device will return to the idle
state once the CS pin has been deasserted.
The WP pin is internally pulled-high and may be left floating if hardware controlled protection
will not be used. However, it is recommended that the WP pin also be externally connected to
V
CC
whenever possible.
Low Input
RESET
Reset: A low state on the reset pin (RESET) will terminate the operation in progress and reset
the internal state machine to an idle state. The device will remain in the reset condition as long
as a low level is present on the RESET pin. Normal operation can resume once the RESET pin
is brought back to a high level.
The device incorporates an internal power-on reset circuit, so there are no restrictions on the
RESET pin during power-on sequences. If this pin and feature is not utilized, then it is
recommended that the RESET pin be driven high externally.
Low Input
V
CC
Device Power Supply: The V
CC
pin is used to supply the source voltage to the device.
Operations at invalid V
CC
voltages may produce spurious results and should not be attempted. — Power
GND Ground: The ground reference for the power supply. GND should be connected to the system
ground. — Ground
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2. Block Diagram
Figure 2-1. Block Diagram
Flash Memory Array
I/O Interface
SCK
CS
RESET
VCC
GND
WP
SOSI
Page (256/264 bytes)
Buffer 1 (256/264 bytes)
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3. Memory Array
To provide optimal flexibility, the AT25PE20 memory array is divided into three levels of granularity comprising of sectors,
blocks, and pages. Figure 3-1, Memory Architecture Diagram illustrates the breakdown of each level and details the
number of pages per sector and block. Program operations to the DataFlash-L can be done at the full page level or at the
byte level (a variable number of bytes). The erase operations can be performed at the chip, sector, block, or page level.
Figure 3-1. Memory Architecture Diagram
Sector 0a = 8 pages
2,048/2,112 bytes
Sector 0b = 120 pages
30,720/31,680 bytes
Block = 2,048/2,112 bytes
8 Pages
Sector 0a
Sector 0b
Page = 256/264 bytes
Page 0
Page 1
Page 6
Page 7
Page 8
Page 9
Page 1,022
Page 1,023
Block 0
Page 14
Page 15
Page 16
Page 17
Page 18
Block 1
Sector Architecture Block Architecture Page Architecture
Block 0
Block 1
Block 14
Block 15
Block 16
Block 17
Block 126
Block 127
Block 30
Block 31
Block 112
Block 113
Sector 1Sector 7
Sector 7 = 128 pages
32,768/33,792 bytes
Block 2
Sector 1 = 128 pages
32,768/33,792 bytes
Sector 6 = 128 pages
32,768/33,792 bytes
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4. Device Operation
The device operation is controlled by instructions from the host processor. The list of instructions and their associated
opcodes are contained in Table 15-1 on page 35 through Table 15-4 on page 36. A valid instruction starts with the falling
edge of CS followed by the appropriate 8-bit opcode and the Buffer or main memory address location. While the CS pin
is low, toggling the SCK pin controls the loading of the opcode and the Buffer or main memory address location through
the SI (Serial Input) pin. All instructions, addresses, and data are transferred with the Most Significant Bit (MSB) first.
Three address bytes are used to address memory locations in either the main memory array or in the Buffer. The three
address bytes will be comprised of a number of dummy bits and a number of actual device address bits, with the number
of dummy bits varying depending on the operation being performed and the selected device page size. Buffer addressing
for the optional DataFlash-L page size (264 bytes) is referenced in the datasheet using the terminology BFA8 - BFA0 to
denote the nine address bits required to designate a byte address within the Buffer. The main memory addressing is
referenced using the terminology PA9 - PA0 and BA8 - BA0, where PA9 - PA0 denotes the 10 address bits required to
designate a page address, and BA8 - BA0 denotes the nine address bits required to designate a byte address within the
page. Therefore, when using the optional DataFlash-L page size, a total of 22 address bits are used.
For the default page size (256 bytes), the Buffer addressing is referenced in the datasheet using the conventional
terminology BFA7 - BFA0 to denote the eight address bits required to designate a byte address within the Buffer. Main
memory addressing is referenced using the terminology A17 - A0, where A17 - A8 denotes the 10 address bits required
to designate a page address, and A7 - A0 denotes the eight address bits required to designate a byte address within a
page. Therefore, when using the default page size, a total of 21 address bits are used.
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5. Read Commands
By specifying the appropriate opcode, data can be read from the main memory or from the data buffer. The DataFlash-L
supports RapidS protocols for Mode 0 and Mode 3. Please see Section 25., "Detailed Bit-level Read Waveforms: RapidS
Mode 0/Mode 3" on page 52 for diagrams detailing the clock cycle sequences for each mode.
5.1 Continuous Array Read (Legacy Command: E8h)
By supplying an initial starting address for the main memory array, the Continuous Array Read command can be utilized
to sequentially read a continuous stream of data from the device by simply providing a clock signal; no additional
addressing information or control signals need to be provided. The DataFlash-L incorporates an internal address counter
that will automatically increment on every clock cycle, allowing one continuous read from memory to be performed
without the need for additional address sequences. To perform a Continuous Array Read using the optional DataFlash-L
page size (264-bytes), an opcode of E8h must be clocked into the device followed by three address bytes (which
comprise the 19-bit page and byte address sequence) and four dummy bytes. The first 10 bits (PA9 - PA0) of the
19-bit address sequence specify which page of the main memory array to read and the last nine bits (BA8 - BA0) of the
19-bit address sequence specify the starting byte address within the page. To perform a Continuous Array Read using
the default page size (256 bytes), the opcode E8h must be clocked into the device followed by three address bytes
(A17 - A0) and four dummy bytes. The dummy bytes that follow the address bytes are needed to initialize the read
operation. Following the dummy bytes, additional clock pulses on the SCK pin will result in data being output on the
SO (Serial Output) pin.
The CS pin must remain low during the loading of the opcode, the address bytes, the dummy bytes and the reading of
data. When the end of a page in main memory is reached during a Continuous Array Read, the device will continue
reading at the beginning of the next page with no delays incurred during the page boundary crossover (the crossover
from the end of one page to the beginning of the next page). When the last bit in the main memory array has been read,
the device will continue reading back at the beginning of the first page of memory. As with crossing over page
boundaries, no delays will be incurred when wrapping around from the end of the array to the beginning of the array.
A low-to-high transition on the CS pin will terminate the read operation and tri-state the output pin (SO). The maximum
SCK frequency allowable for the Continuous Array Read is defined by the f
CAR1
specification. The Continuous Array
Read bypasses the data buffer and leaves the contents of the Buffer unchanged.
Note: This command is not recommended for new designs.
5.2 Continuous Array Read (High Frequency Mode: 0Bh Opcode)
This command can be used to read the main memory array sequentially at the highest possible operating clock
frequency up to the maximum specified by f
CAR1
. To perform a Continuous Array Read using the optional DataFlash-L
page size (264 bytes), the CS pin must first be asserted, and then an opcode of 0Bh must be clocked into the device
followed by three address bytes and one dummy byte. The first 10 bits (PA9 - PA0) of the 19-bit address sequence
specify which page of the main memory array to read and the last nine bits (BA8 - BA0) of the 19-bit address sequence
specify the starting byte address within the page. To perform a Continuous Array Read using the default page size
(256 bytes), the opcode 0Bh must be clocked into the device followed by three address bytes (A17 - A0) and one dummy
byte. Following the dummy byte, additional clock pulses on the SCK pin will result in data being output on the SO pin.
The CS pin must remain low during the loading of the opcode, the address bytes, the dummy byte, and the reading of
data. When the end of a page in the main memory is reached during a Continuous Array Read, the device will continue
reading at the beginning of the next page with no delays incurred during the page boundary crossover (the crossover
from the end of one page to the beginning of the next page). When the last bit in the main memory array has been read,
the device will continue reading back at the beginning of the first page of memory. As with crossing over page
boundaries, no delays will be incurred when wrapping around from the end of the array to the beginning of the array.
A low-to-high transition on the CS pin will terminate the read operation and tri-state the output pin (SO). The maximum
SCK frequency allowable for the Continuous Array Read is defined by the f
CAR1
specification. The Continuous Array
Read bypasses the data buffer and leaves the contents of the Buffer unchanged.
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5.3 Continuous Array Read (Low Frequency Mode: 03h Opcode)
This command can be used to read the main memory array sequentially at lower clock frequencies up to maximum
specified by f
CAR2
. Unlike the previously described read commands, this Continuous Array Read command for lower
clock frequencies does not require the clocking in of dummy bytes after the address byte sequence. To perform a
Continuous Array Read using the optional DataFlash-L page size (264 bytes), the CS pin must first be asserted, and then
an opcode of 03h must be clocked into the device followed by three address bytes (which comprise the 24-bit page and
byte address sequence). The first 10 bits (PA9 - PA0) of the 19-bit address sequence specify which page of the main
memory array to read, and the last nine bits (BA8 - BA0) of the 19-bit address sequence specify the starting byte address
within the page. To perform a Continuous Array Read using the default page size (256 bytes), the opcode 03h must be
clocked into the device followed by three address bytes (A17 - A0). Following the address bytes, additional clock pulses
on the SCK pin will result in data being output on the SO pin.
The CS pin must remain low during the loading of the opcode, the address bytes, and the reading of data. When the end
of a page in the main memory is reached during a Continuous Array Read, the device will continue reading at the
beginning of the next page with no delays incurred during the page boundary crossover (the crossover from the end of
one page to the beginning of the next page). When the last bit in the main memory array has been read, the device will
continue reading back at the beginning of the first page of memory. As with crossing over page boundaries, no delays will
be incurred when wrapping around from the end of the array to the beginning of the array.
A low-to-high transition on the CS pin will terminate the read operation and tri-state the output pin (SO). The maximum
SCK frequency allowable for the Continuous Array Read is defined by the f
CAR2
specification. The Continuous Array
Read bypasses the data buffer and leaves the contents of the Buffer unchanged.
5.4 Continuous Array Read (Low Power Mode: 01h Opcode)
This command is ideal for applications that want to minimize power consumption and do not need to read the memory
array at high frequencies. Like the 03h opcode, this Continuous Array Read command allows reading the main memory
array sequentially without the need for dummy bytes to be clocked in after the address byte sequence. The memory can
be read at clock frequencies up to maximum specified by f
CAR3
. To perform a Continuous Array Read using the optional
DataFlash-L page size (264 bytes), the CS pin must first be asserted, and then an opcode of 01h must be clocked into
the device followed by three address bytes (which comprise the 24-bit page and byte address sequence). The first 10
bits
(PA9 - PA0) of the 19-bit address sequence specify which page of the main memory array to read and the last nine bits
(BA8 - BA0) of the 19-bit address sequence specify the starting byte address within the page. To perform a Continuous
Array Read using the default page size (256 bytes), the opcode 01h must be clocked into the device followed by three
address bytes (A17 - A0). Following the address bytes, additional clock pulses on the SCK pin will result in data being
output on the SO pin.
The CS pin must remain low during the loading of the opcode, the address bytes, and the reading of data. When the end
of a page in the main memory is reached during a Continuous Array Read, the device will continue reading at the
beginning of the next page with no delays incurred during the page boundary crossover (the crossover from the end of
one page to the beginning of the next page). When the last bit in the main memory array has been read, the device will
continue reading back at the beginning of the first page of memory. As with crossing over page boundaries, no delays will
be incurred when wrapping around from the end of the array to the beginning of the array.
A low-to-high transition on the CS pin will terminate the read operation and tri-state the output pin (SO). The maximum
SCK frequency allowable for the Continuous Array Read is defined by the f
CAR3
specification. The Continuous Array
Read bypasses the data buffer and leaves the contents of the Buffer unchanged.
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5.5 Main Memory Page Read
A Main Memory Page Read allows the user to read data directly from any one of the 1,024 pages in the main memory,
bypassing the data buffer and leaving the contents of the Buffer unchanged. To start a Main Memory Page Read using
the optional DataFlash-L page size (264 bytes), the CS pin must first be asserted then an opcode of D2h must be
clocked into the device followed by three address bytes
(which comprise the 24-bit page and byte address sequence)
and four dummy bytes.
The first 10 bits (PA9 - PA0) of the 19-bit address sequence specify which page of the main
memory array to read, and the last nine bits (BA8 - BA0) of the 19-bit address sequence specify the starting byte address
within the page. To perform a Main Memory Page Read with the default page size (256 bytes), the opcode D2h must be
clocked into the device followed by three address bytes (A17 - A0) and four dummy bytes. The first 10 bits (A17 - A8) of
the
18-bit address sequence specify which page of the main memory array to read, and the last eight bits (A7 - A0) of the
18-bit address sequence specify the starting byte address within that page. The dummy bytes that follow the address
bytes are sent to initialize the read operation. Following the dummy bytes, the additional pulses on SCK result in data
being output on the SO (Serial Output) pin.
The CS pin must remain low during the loading of the opcode, the address bytes, the dummy bytes, and the reading of
data. Unlike the Continuous Array Read command, when the end of a page in main memory is reached, the device will
continue reading back at the beginning of the same page rather than the beginning of the next page.
A low-to-high transition on the CS pin will terminate the read operation and tri-state the output pin (SO). The maximum
SCK frequency allowable for the Main Memory Page Read is defined by the f
SCK
specification. The Main Memory Page
Read bypasses the data buffer and leaves the contents of the Buffer unchanged.
5.6 Buffer Read
The data buffer can be accessed independently from the main memory array, and utilizing the Buffer Read command
allows data to be sequentially read directly from the Buffer. Two opcodes, D4h or D1h, can be used for the Buffer Read
command. The use of each opcode depends on the maximum SCK frequency that will be used to read data from the
Buffer. The D4h opcode can be used at any SCK frequency up to the maximum specified by f
CAR
while the D1h opcode
can be used for lower frequency read operations up to the maximum specified by f
CAR2
.
To perform a Buffer Read using the optional DataFlash-L buffer size (264 bytes), the opcode must be clocked into the
device followed by three address bytes comprised of 15 dummy bits and nine buffer address bits (BFA8 -BFA0). To
perform a Buffer Read using the default buffer size (256 bytes), the opcode must be clocked into the device followed by
three address bytes comprised of 16 dummy bits and eight address bits (A7 - A0). Following the address bytes, one
dummy byte must be clocked into the device to initialize the read operation if using opcode D4h. The CS must remain low
during the loading of the opcode, the address bytes, the dummy byte (for opcode D4h only), and the reading of data.
When the end of a buffer is reached, the device will continue reading back at the beginning of the Buffer. A
low-to-high transition on the CS pin will terminate the read operation and tri-state the output pin (SO).
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6. Program and Erase Commands
6.1 Buffer Write
Utilizing the Buffer Write command allows data clocked in from the SI pin to be written directly into the data buffer.
To load data into the Buffer using the optional DataFlash-L buffer size (264 bytes), an opcode of 84h must be clocked
into the device followed by three address bytes comprised of 15 dummy bits and nine buffer address bits (BFA8 - BFA0).
The nine buffer address bits specify the first byte in the Buffer to be written.
To load data into the Buffer using the default buffer size (256 bytes), an opcode of 84h must be clocked into the device
followed by 16 dummy bits and eight address bits (A7 - A0). The eight address bits specify the first byte in the Buffer to
be written.
After the last address byte has been clocked into the device, data can then be clocked in on subsequent clock cycles. If
the end of the data buffer is reached, the device will wrap around back to the beginning of the Buffer. Data will continue
to be loaded into the Buffer until a low-to-high transition is detected on the CS pin.
6.2 Buffer to Main Memory Page Program with Built-In Erase
The Buffer to Main Memory Page Program with Built-In Erase command allows data that is stored in the Buffer to be
written into an erased or programmed page in the main memory array. It is not necessary to pre-erase the page in main
memory to be written because this command will automatically erase the selected page prior to the program cycle.
To perform a Buffer to Main Memory Page Program with Built-In Erase using the optional DataFlash-L page size
(264 bytes), an opcode of 83h must be clocked into the device followed by three address bytes comprised of five dummy
bits,10 page address bits (PA9 - PA0) that specify the page in the main memory to be written, and nine dummy bits.
To perform a Buffer to Main Memory Page Program with Built-In Erase using the default page size (256 bytes), an
opcode of 83h must be clocked into the device followed by three address bytes comprised of six dummy bits, 10 page
address bits (A17 - A8) that specify the page in the main memory to be written, and eight dummy bits.
When a low-to-high transition occurs on the CS pin, the device will first erase the selected page in main memory
(the erased state is a Logic 1) and then program the data stored in the Buffer into that same page in main memory. Both
the erasing and the programming of the page are internally self-timed and should take place in a maximum time of t
EP
.
During this time, the RDY/BUSY bit in the Status Register will indicate that the device is busy.
The device also incorporates intelligent erase and program algorithms that can detect when a byte location fails to erase
or program properly. If an erase or programming error arises, it will be indicated by the EPE bit in the Status Register.
6.3 Buffer to Main Memory Page Program without Built-In Erase
The Buffer to Main Memory Page Program without Built-In Erase command allows data that is stored in the Buffer to be
written into a pre-erased page in the main memory array. It is necessary that the page in main memory to be written be
previously erased in order to avoid programming errors.
To perform a Buffer to Main Memory Page Program without Built-In Erase using the optional DataFlash-L page size
(264 bytes), an opcode of 88h must be clocked into the device followed by three address bytes comprised of five dummy
bits,10 page address bits (PA9 - PA0) that specify the page in the main memory to be written, and nine dummy bits.
To perform a Buffer to Main Memory Page Program using the default page size (256 bytes), an opcode 88h must be
clocked into the device followed by three address bytes comprised of six dummy bits, 10 page address bits (A17 - A8)
that specify the page in the main memory to be written, and eight dummy bits.
When a low-to-high transition occurs on the CS pin, the device will program the data stored in the Buffer into the
specified page in the main memory. The page in main memory that is being programmed must have been previously
erased using one of the erase commands (Page Erase, Block Erase, Sector Erase, or Chip Erase). The programming of
the page is internally self-timed and should take place in a maximum time of t
P
. During this time, the RDY/BUSY bit in the
Status Register will indicate that the device is busy.
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The device also incorporates an intelligent programming algorithm that can detect when a byte location fails to program
properly. If a programming error arises, it will be indicated by the EPE bit in the Status Register.
6.4 Main Memory Page Program through Buffer with Built-In Erase
The Main Memory Page Program through Buffer with Built-In Erase command combines the Buffer Write and Buffer to
Main Memory Page Program with Built-In Erase operations into a single operation to help simplify application firmware
development. With the Main Memory Page Program through Buffer with Built-In Erase command, data is first clocked
into the Buffer, the addressed page in memory is then automatically erased, and then the contents of the Buffer are
programmed into the just-erased main memory page.
To perform a Main Memory Page Program through Buffer using the optional DataFlash-L page size (264 bytes), an
opcode of 82h must first be clocked into the device followed by three address bytes comprised of five dummy bits,
10 page address bits (PA9 - PA0) that specify the page in the main memory to be written, and nine buffer address bits
(BFA8 - BFA0) that select the first byte in the Buffer to be written.
To perform a Main Memory Page Program through Buffer using the default page size (256 bytes), an opcode of 82h must
first be clocked into the device followed by three address bytes comprised of six dummy bits, 10 page address bits
(A17 - A8) that specify the page in the main memory to be written, and eight address bits (A7 - A0) that selects the first
byte in the Buffer to be written.
After all address bytes have been clocked in, the device will take data from the input pin (SI) and store it in the Buffer. If
the end of the Buffer is reached, the device will wrap around back to the beginning of the Buffer. When there is a
low-to-high transition on the CS pin, the device will first erase the selected page in main memory (the erased state is a
Logic 1) and then program the data stored in the Buffer into that main memory page. Both the erasing and the
programming of the page are internally self-timed and should take place in a maximum time of t
EP
. During this time, the
RDY/BUSY bit in the Status Register will indicate that the device is busy.
The device also incorporates intelligent erase and programming algorithms that can detect when a byte location fails to
erase or program properly. If an erase or program error arises, it will be indicated by the EPE bit in the Status Register.
6.5 Main Memory Byte/Page Program through Buffer without Built-In Erase
The Main Memory Byte/Page Program through the Buffer without Built-In Erase combines both the Buffer Write and
Buffer to Main Memory Program without Built-In Erase operations to allow any number of bytes (1 to 256/264 bytes) to be
programmed directly into previously erased locations in the main memory array. With the Main Memory Byte/Page
Program through Buffer without Built-In Erase command, data is first clocked into Buffer, and then only the bytes clocked
into the Buffer are programmed into the pre-erased byte locations in main memory. Multiple bytes up to the page size can
be entered with one command sequence.
To perform a Main Memory Byte/Page Program through the Buffer using the optional DataFlash-L page size (264 bytes),
an opcode of 02h must first be clocked into the device followed by three address bytes comprised of five dummy bits,
10 page address bits (PA9 - PA0) that specify the page in the main memory to be written, and nine buffer address bits
(BFA8 - BFA0) that select the first byte in the Buffer to be written. After all address bytes are clocked in, the device will
take data from the input pin (SI) and store it in the Buffer. Any number of bytes (1 to 264) can be entered. If the end of the
Buffer is reached, then the device will wrap around back to the beginning of the Buffer.
To perform a Main Memory Byte/Page Program through the Buffer using the default page size (256 bytes), an opcode of
02h must first be clocked into the device followed by three address bytes comprised of six dummy bits, 10 page address
bits (PA9 - PA0) that specify the page in the main memory to be written, and eight address bits (A7 - A0) that selects the
first byte in the Buffer to be written. After all address bytes are clocked in, the device will take data from the input pin (SI)
and store it in the Buffer. Any number of bytes (1 to 256) can be entered. If the end of the Buffer is reached, then the
device will wrap around back to the beginning of the Buffer. When using the default page size, the page and buffer
address bits correspond to an 18-bit logical address (A17-A0) in the main memory.
After all data bytes have been clocked into the device, a low-to-high transition on the CS pin will start the program
operation in which the device will program the data stored in the Buffer into the main memory array. Only the data bytes
that were clocked into the device will be programmed into the main memory.
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Example: If only two data bytes were clocked into the device, then only two bytes will be programmed into main
memory and the remaining bytes in the memory page will remain in their previous state.
The CS pin must be deasserted on a byte boundary (multiples of eight bits); otherwise the operation will be aborted and
no data will be programmed. The programming of the data bytes is internally self-timed and should take place in a
maximum time of t
P
(the program time will be a multiple of the t
BP
time depending on the number of bytes being
programmed). During this time, the RDY/BUSY bit in the Status Register will indicate that the device is busy.
The device also incorporates an intelligent programming algorithm that can detect when a byte location fails to program
properly. If a programming error arises, it will be indicated by the EPE bit in the Status Register.
6.6 Page Erase
The Page Erase command can be used to individually erase any page in the main memory array allowing the Buffer to
Main Memory Page Program without Built-In Erase command or the Main Memory Byte/Page Program through Buffer
command to be utilized at a later time.
To perform a Page Erase with the optional DataFlash-L page size (264 bytes), an opcode of 81h must be clocked into the
device followed by three address bytes comprised of five dummy bits, 10 page address bits (PA9 - PA0) that specify the
page in the main memory to be erased, and nine dummy bits.
To perform a Page Erase with the default page size (256 bytes), an opcode of 81h must be clocked into the device
followed by three address bytes comprised of six dummy bits, 10 page address bits (A17 - A8) that specify the page in
the main memory to be erased, and eight dummy bits.
When a low-to-high transition occurs on the CS pin, the device will erase the selected page (the erased state is a
Logic 1). The erase operation is internally self-timed and should take place in a maximum time of t
PE
. During this time, the
RDY/BUSY bit in the Status Register will indicate that the device is busy.
The device also incorporates an intelligent erase algorithm that can detect when a byte location fails to erase properly. If
an erase error arises, it will be indicated by the EPE bit in the Status Register.
6.7 Block Erase
The Block Erase command can be used to erase a block of eight pages at one time. This command is useful when
needing to pre-erase larger amounts of memory and is more efficient than issuing eight separate Page Erase
commands.
To perform a Block Erase with the optional DataFlash-L page size (264 bytes), an opcode of 50h must be clocked into
the device followed by three address bytes comprised of five dummy bits, seven page address bits (PA9 - PA3), and
12 dummy bits. The seven page address bits are used to specify which block of eight pages is to be erased.
To perform a Block Erase with the default page size (256 bytes), an opcode of 50h must be clocked into the device
followed by three address bytes comprised of six dummy bits, seven page address bits (A17 - A11), and 11 dummy bits.
The seven page address bits are used to specify which block of eight pages is to be erased.
When a low-to-high transition occurs on the CS pin, the device will erase the selected block of eight pages. The erase
operation is internally self-timed and should take place in a maximum time of t
BE
. During this time, the RDY/BUSY bit in
the Status Register will indicate that the device is busy.
The device also incorporates an intelligent erase algorithm that can detect when a byte location fails to erase properly. If
an erase error arises, it will be indicated by the EPE bit in the Status Register.
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Table 6-1. Block Erase Addressing
6.8 Sector Erase
The Sector Erase command can be used to individually erase any sector in the main memory.
The main memory array is comprised of nine sectors, and only one sector can be erased at a time. To perform an erase
of Sector 0a or Sector 0b with the optional DataFlash-L page size (264 bytes), an opcode of 7Ch must be clocked into the
device followed by three address bytes comprised of five dummy bits, seven page address bits (PA9 - PA3), and
12 dummy bits. To perform a Sector 1-7 erase, an opcode of 7Ch must be clocked into the device followed by three
address bytes comprised of five dummy bits, three page address bits (PA9 - PA7), and 16 dummy bits.
To perform a Sector 0a or Sector 0b erase with the default page size (256 bytes), an opcode of 7Ch must be clocked into
the device followed by three address bytes comprised of six dummy bits, seven page address bits (A17 - A11), and
11 dummy bits. To perform a Sector 1-7 erase, an opcode of 7Ch must be clocked into the device followed by six dummy
bits, three page address bits (A17 - A15), and 15 dummy bits.
The page address bits are used to specify any valid address location within the sector is to be erased. When a
low-to-high transition occurs on the CS pin, the device will erase the selected sector. The erase operation is internally
self-timed and should take place in a maximum time of t
SE
. During this time, the RDY/BUSY bit in the Status Register will
indicate that the device is busy.
The device also incorporates an intelligent erase algorithm that can detect when a byte location fails to erase properly. If
an erase error arises, it will be indicated by the EPE bit in the Status Register.
PA9/A17 PA8/A16 PA7/A15 PA6/A14 PA5/A13 PA4/A12 PA3/A11 PA2/A10 PA1/A9 PA0/A8 Block
0000000XXX0
0000001XXX1
0000010XXX2
0000011XXX3
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
1 1 1 1 1 0 0 X X X 124
1 1 1 1 1 0 1 X X X 125
1 1 1 1 1 1 0 X X X 126
1 1 1 1 1 1 1 X X X 127
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Table 6-2. Sector Erase Addressing
6.9 Chip Erase
The Chip Erase command allows the entire main memory array to be erased at one time.
To execute the Chip Erase command, a 4-byte command sequence of C7h, 94h, 80h, and 9Ah must be clocked into the
device. Since the entire memory array is to be erased, no address bytes need to be clocked into the device and any data
clocked in after the opcode will be ignored. After the last bit of the opcode sequence has been clocked in, the CS pin
must be deasserted to start the erase process. The erase operation is internally self-timed and should take place in a
time of t
CE
. During this time, the RDY/BUSY bit in the Status Register will indicate that the device is busy.
The Chip Erase command will not affect sectors that are protected or locked down; the contents of those sectors will
remain unchanged. Only those sectors that are not protected or locked down will be erased.
The WP pin can be asserted while the device is erasing, but protection will not be activated until the internal erase cycle
completes.
The device also incorporates an intelligent erase algorithm that can detect when a byte location fails to erase properly. If
an erase error arises, it will be indicated by the EPE bit in the Status Register.
Table 6-3. Chip Erase Command
Figure 6-1. Chip Erase
PA9/A17 PA8/A16 PA7/A15 PA6/A14 PA5/A13 PA4/A12 PA3/A11 PA2/A10 PA1/A9 PA0/A8 Sector
0 0 0 0 0 0 0 X X X 0a
0 0 0 0 0 0 1 X X X 0b
0 0 1 X X X X X X X 1
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
1 0 1 X X X X X X X 5
1 1 0 X X X X X X X 6
1 1 1 X X X X X X X 7
Command Byte 1 Byte 2 Byte 3 Byte 4
Chip Erase C7h 94h 80h 9Ah
C7h 94h 80h 9Ah
CS
Each transition represents eight bits
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6.10 Read-Modify-Write
A completely self-contained read-modify-write operation can be performed to reprogram any number of sequential bytes
in a page in the main memory array without affecting the rest of the bytes in the same page. This command allows the
device to easily emulate an EEPROM by providing a method to modify a single byte or more in the main memory in a
single operation, without the need for pre-erasing the memory or the need for any external RAM buffers. The
Read-Modify-Write command is essentially a combination of the Main Memory Page to Buffer Transfer, Buffer Write, and
Buffer to Main Memory Page Program with Built-in Erase commands.
To perform a Read-Modify-Write using the optional DataFlash-L page size (264 bytes), an opcode of 58h for Buffer 1
must be clocked into the device followed by three address bytes comprised of five dummy bits, 10 page address bits
(PA9 - PA0) that specify the page in the main memory to be written and nine byte address bits (BA8-BA0) that designate
the starting byte address within the page to reprogram.
To perform a Read-Modify-Write using the default page size (256 bytes), an opcode of 58h for Buffer 1 must be clocked
into the device followed by three address bytes comprised of six dummy bits, 10 page address bits (A17 - A8) that
specify the page in the main memory to be written and eight byte address bits (A7-A0) that designate the starting byte
address within the page to reprogram.
After the address bytes have been clocked in, any number of sequential data bytes from one to 256/264 bytes can be
clocked into the device. If the end of the buffer is reached when clocking in the data, then the device will wrap around
back to the beginning of the buffer. After all data bytes have been clocked into the device, a low-to-high transition on the
CS pin will start the self-contained, internal read-modify-write operation. Only the data bytes that were clocked into the
device will be reprogrammed in the main memory.
Example: If only one data byte was clocked into the device, then only one byte in main memory will be reprogrammed
and the remaining bytes in the main memory page will remain in their previous state.
The CS pin must be deasserted on a byte boundary (multiples of eight bits); otherwise, the operation will be aborted and
no data will be programmed. The reprogramming of the data bytes is internally self-timed and should take place in a
maximum time of t
P
. During this time, the RDY/BUSY bit in the Status Register will indicate that the device is busy.
The device also incorporates an intelligent erase and programming algorithm that can detect when a byte location fails to
erase or program properly. If an erase or program error arises, it will be indicated by the EPE bit in the Status Register.
Note: The Read-Modify-Write command uses the same opcodes as the Auto Page Rewrite command. If no data bytes
are clocked into the device, then the device will perform an Auto Page Rewrite operation. See the Auto Page
Rewrite command description on page 22 for more details.
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7. Sector Protection
Two protection methods, hardware and software controlled, are provided for protection against inadvertent or erroneous
program and erase cycles. The software controlled method relies on the use of software commands to enable and
disable sector protection while the hardware controlled method employs the use of the Write Protect (WP) pin. The
selection of which sectors that are to be protected or unprotected against program and erase operations is specified in
the nonvolatile Sector Protection Register. The status of whether or not sector protection has been enabled or disabled
by either the software or the hardware controlled methods can be determined by checking the Status Register.
7.1 Software Sector Protection
Software controlled protection is useful in applications in which the WP pin is not or cannot be controlled by a host
processor. In such instances, the WP pin may be left floating (the WP pin is internally pulled high) and sector protection
can be controlled using the Enable Sector Protection and Disable Sector Protection commands.
If the device is power cycled, then the software controlled protection will be disabled. Once the device is powered up, the
Enable Sector Protection command should be reissued if sector protection is desired and if the WP pin is not used.
7.1.1 Enable Sector Protection
Sectors specified for protection in the Sector Protection Register can be protected from program and erase operations by
issuing the Enable Sector Protection command. To enable the sector protection, a 4-byte command sequence of
3Dh, 2Ah, 7Fh, and A9h must be clocked into the device. After the last bit of the opcode sequence has been clocked in,
the CS pin must be deasserted to enable the Sector Protection.
Table 7-1. Enable Sector Protection Command
Figure 7-1. Enable Sector Protection
7.1.2 Disable Sector Protection
To disable the sector protection, a 4-byte command sequence of 3Dh, 2Ah, 7Fh, and 9Ah must be clocked into the
device. After the last bit of the opcode sequence has been clocked in, the CS pin must be deasserted to disable the
sector protection.
Table 7-2. Disable Sector Protection Command
Figure 7-2. Disable Sector Protection
Command Byte 1 Byte 2 Byte 3 Byte 4
Enable Sector Protection 3Dh 2Ah 7Fh A9h
3Dh 2Ah 7Fh 9Ah
CS
Each transition represents eight bits
SI
A9h
Command Byte 1 Byte 2 Byte 3 Byte 4
Disable Sector Protection 3Dh 2Ah 7Fh 9Ah
3Dh 2Ah 7Fh 9Ah
CS
Each transition represents eight bits
SI
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7.2 Hardware Controlled Protection
Sectors specified for protection in the Sector Protection Register and the Sector Protection Register itself can be
protected from program and erase operations by asserting the WP pin and keeping the pin in its asserted state. The
Sector Protection Register and any sector specified for protection cannot be erased or programmed as long as the WP
pin is asserted. In order to modify the Sector Protection Register, the WP pin must be deasserted. If the WP pin is
permanently connected to GND, then the contents of the Sector Protection Register cannot be changed. If the WP pin is
deasserted or permanently connected to V
CC
, then the contents of the Sector Protection Register can be modified.
The WP pin will override the software controlled protection method but only for protecting the sectors.
Example: If the sectors were not previously protected by the Enable Sector Protection command, then simply
asserting the WP pin would enable the sector protection within the maximum specified t
WPE
time. When the
WP pin is deasserted, however, the sector protection would no longer be enabled (after the maximum
specified t
WPD
time) as long as the Enable Sector Protection command was not issued while the WP pin was
asserted. If the Enable Sector Protection command was issued before or while the WP pin was asserted,
then simply deasserting the WP pin would not disable the sector protection. In this case, the Disable Sector
Protection command would need to be issued while the WP pin is deasserted to disable the sector
protection. The Disable Sector Protection command is also ignored whenever the WP pin is asserted.
A noise filter is incorporated to help protect against spurious noise that my inadvertently assert or deassert the WP pin.
Figure 7-3 and Table 7-3 detail the sector protection status for various scenarios of the WP pin, the Enable Sector
Protection command, and the Disable Sector Protection command.
Figure 7-3. WP Pin and Protection Status
Table 7-3. WP Pin and Protection Status
Time
Period WP Pin Enable Sector Protection Command
Disable Sector
Protection Command
Sector
Protection
Status
Sector
Protection
Register
1 High
Command Not Issued Previously X Disabled Read/Write
— Issue Command Disabled Read/Write
Issue Command — Enabled Read/Write
2 Low X X Enabled Read
3 High
Command Issued During Period 1 or 2 Not Issued Yet Enabled Read/Write
— Issue Command Disabled Read/Write
Issue Command — Enabled Read/Write
WP
1 2 3
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7.3 Sector Protection Register
The nonvolatile Sector Protection Register specifies which sectors are to be protected or unprotected with either the
software or hardware controlled protection methods. The Sector Protection Register contains eight bytes of data, of
which byte locations 0 through 7 contain values that specify whether Sectors 0 through 7 will be protected or
unprotected. The Sector Protection Register is user modifiable and must be erased before it can be reprogrammed.
Table 7-4 illustrates the format of the Sector Protection Register.
Table 7-4. Sector Protection Register
Note: 1. The default values for bytes 0 through 7 are 00h when shipped from Adesto.
Table 7-5. Sector 0 (0a, 0b) Sector Protection Register Byte Value
Note: 1. X = Don’t care
7.3.1 Erase Sector Protection Register
In order to modify and change the values of the Sector Protection Register, it must first be erased using the Erase Sector
Protection Register command.
To erase the Sector Protection Register, a 4-byte command sequence of 3Dh, 2Ah, 7Fh, and CFh must be clocked into
the device. After the last bit of the opcode sequence has been clocked in, the CS pin must be deasserted to initiate the
internally self-timed erase cycle. The erasing of the Sector Protection Register should take place in a maximum time of
t
PE
. During this time, the RDY/BUSY bit in the Status Register will indicate that the device is busy. If the device is
powered-down before the completion of the erase cycle, then the contents of the Sector Protection Register cannot be
guaranteed.
The Sector Protection Register can be erased with sector protection enabled or disabled. Since the erased state (FFh) of
each byte in the Sector Protection Register is used to indicate that a sector is specified for protection, leaving the sector
protection enabled during the erasing of the register allows the protection scheme to be more effective in the prevention
of accidental programming or erasing of the device. If for some reason an erroneous program or erase command is sent
to the device immediately after erasing the Sector Protection Register and before the register can be reprogrammed,
then the erroneous program or erase command will not be processed because all sectors would be protected.
Table 7-6. Erase Sector Protection Register Command
Sector Number 0 (0a, 0b) 1 to 7
Protected
See Table 7-5
FFh
Unprotected 00h
Bit 7:6 Bit 5:4 Bit 3:2 Bit 1:0
Data Value
Sector 0a
(Page 0-7)
Sector 0b
(Page 8-127) N/A N/A
Sectors 0a and 0b Unprotected 00 00 XX XX 0Xh
Protect Sector 0a 11 00 XX XX CXh
Protect Sector 0b 00 11 XX XX 3Xh
Protect Sectors 0a and 0b 11 11 XX XX FXh
Command Byte 1 Byte 2 Byte 3 Byte 4
Erase Sector Protection Register 3Dh 2Ah 7Fh CFh
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Figure 7-4. Erase Sector Protection Register
7.3.2 Program Sector Protection Register
Once the Sector Protection Register has been erased, it can be reprogrammed using the Program Sector Protection
Register command.
To program the Sector Protection Register, a 4-byte command sequence of 3Dh, 2Ah, 7Fh, and FCh must be clocked
into the device followed by eight bytes of data corresponding to Sectors 0 through 7. After the last bit of the opcode
sequence and data have been clocked in, the CS pin must be deasserted to initiate the internally self-timed program
cycle. The programming of the Sector Protection Register should take place in a maximum time of t
P
. During this time,
the RDY/BUSY bit in the Status Register will indicate that the device is busy. If the device is powered-down before the
completion of the erase cycle, then the contents of the Sector Protection Register cannot be guaranteed.
If the proper number of data bytes is not clocked in before the CS pin is deasserted, then the protection status of the
sectors corresponding to the bytes not clocked in cannot be guaranteed.
Example: If only the first two bytes are clocked in instead of the complete eight bytes, then the protection status of the
last six sectors cannot be guaranteed. Furthermore, if more than eight bytes of data is clocked into the
device, then the data will wrap back around to the beginning of the register. For instance, if nine bytes of
data are clocked in, then the ninth byte will be stored at byte location 0 of the Sector Protection Register.
The data bytes clocked into the Sector Protection Register need to be valid values (0Xh, 3Xh, CXh, and FXh for Sector
0a or Sector 0b, and 00h or FFh for other sectors) in order for the protection to function correctly. If a non-valid value is
clocked into a byte location of the Sector Protection Register, then the protection status of the sector corresponding to
that byte location cannot be guaranteed.
Example: If a value of 17h is clocked into byte location 2 of the Sector Protection Register, then the protection status
of Sector 2 cannot be guaranteed.
The Sector Protection Register can be reprogrammed while the sector protection is enabled or disabled. Being able to
reprogram the Sector Protection Register with the sector protection enabled allows the user to temporarily disable the
sector protection to an individual sector rather than disabling sector protection completely.
The Program Sector Protection Register command utilizes the internal buffer for processing. Therefore, the contents of
the Buffer will be altered from its previous state when this command is issued.
Table 7-7. Program Sector Protection Register Command
Figure 7-5. Program Sector Protection Register
3Dh 2Ah 7Fh CFh
CS
Each transition represents eight bits
SI
Command Byte 1 Byte 2 Byte 3 Byte 4
Program Sector Protection Register 3Dh 2Ah 7Fh FCh
Data Byte
n
3Dh 2Ah 7Fh FCh Data Byte
n + 1
CS
Each transition represents eight bits
SI Data Byte
n + 7
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7.3.3 Read Sector Protection Register
To read the Sector Protection Register, an opcode of 32h and three dummy bytes must be clocked into the device. After
the last bit of the opcode and dummy bytes have been clocked in, any additional clock pulses on the SCK pin will result
in the Sector Protection Register contents being output on the SO pin. The first byte (byte location 0) corresponds to
Sector 0 (0a and 0b), the second byte corresponds to Sector 1, and the last byte (byte location 7) corresponds to
Sector 7. Once the last byte of the Sector Protection Register has been clocked out, any additional clock pulses will result
in undefined data being output on the SO pin. The CS pin must be deasserted to terminate the Read Sector Protection
Register operation and put the output into a high-impedance state.
Table 7-8. Read Sector Protection Register Command
Note: 1. XX = Dummy byte
Figure 7-6. Read Sector Protection Register
7.3.4 About the Sector Protection Register
The Sector Protection Register is subject to a limit of 10,000 erase/program cycles. Users are encouraged to carefully
evaluate the number of times the Sector Protection Register will be modified during the course of the application’s life
cycle. If the application requires that the Security Protection Register be modified more than the specified limit of 10,000
cycles because the application needs to temporarily unprotect individual sectors (sector protection remains enabled
while the Sector Protection Register is reprogrammed), then the application will need to limit this practice. Instead, a
combination of temporarily unprotecting individual sectors along with disabling sector protection completely will need to
be implemented by the application to ensure that the limit of 10,000 cycles is not exceeded.
Command Byte 1 Byte 2 Byte 3 Byte 4
Read Sector Protection Register 32h XXh XXh XXh
32h XX XX XX
Data
n
Data
n + 1
CS
SI
SO
Each transition represents eight bits
Data
n + 7
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8. Security Features
8.1 Security Register
The device contains a specialized Security Register that can be used for purposes such as unique device serialization or
locked key storage. The register is comprised of a total of 128 bytes (byte locations 0 through 127). All 128 bytes of the
Security Register are factory programmed by Adesto and will contain a unique value for each device. The factory
programmed data is fixed and cannot be changed.
Table 8-1. Security Register
8.1.1 Reading the Security Register
To read the Security Register, an opcode of 77h and three dummy bytes must be clocked into the device. After the last
dummy bit has been clocked in, the contents of the Security Register can be clocked out on the SO pin. After the last
byte of the Security Register has been read, additional pulses on the SCK pin will result in undefined data being output
on the SO pin.
Deasserting the CS pin will terminate the Read Security Register operation and put the SO pin into a high-impedance
state.
Figure 8-1. Read Security Register
Security Register Byte Number
0 · · · 127
Data Type Factory Programmed by Adesto
77h XX XX XX
Data
n
Data
n + 1
CS
Data
n + x
SI
SO
Each transition represents eight bits
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9. Additional Commands
9.1 Main Memory Page to Buffer Transfer
A page of data can be transferred from the main memory to the Buffer. To transfer a page of data using the optional
DataFlash-L page size (264 bytes), an opcode of 53h must be clocked into the device followed by three address bytes
comprised of five dummy bits, 10 page address bits (PA9 - PA0) which specify the page in main memory to be
transferred, and nine dummy bits. To transfer a page of data using the default page size (256 bytes), an opcode of 53h
must be clocked into the device followed by three address bytes comprised of six dummy bits, 10 page address bits
(A17 - A8) which specify the page in the main memory to be transferred, and eight dummy bits.
The CS pin must be low while toggling the SCK pin to load the opcode and the three address bytes from the input
pin (SI). The transfer of the page of data from the main memory to the Buffer will begin when the CS pin transitions from
a low to a high state. During the page transfer time (t
XFR
), the RDY/BUSY bit in the Status Register can be read to
determine whether or not the transfer has been completed.
9.2 Main Memory Page to Buffer Compare
A page of data in main memory can be compared to the data in the Buffer as a method to ensure that data was
successfully programmed after a Buffer to Main Memory Page Program command. To compare a page of data with the
optional DataFlash-L page size (264 bytes), an opcode of 60h must be clocked into the device followed by three address
bytes comprised of five dummy bits, 10 page address bits (PA9 - PA0) which specify the page in the main memory to be
compared to the Buffer, and nine dummy bits. To compare a page of data with the default page size (256 bytes), an
opcode of 60h must be clocked into the device followed by three address bytes comprised of six dummy bits, 10 page
address bits (A17 - A8) which specify the page in the main memory to be compared to the Buffer, and eight dummy bits.
The CS pin must be low while toggling the SCK pin to load the opcode and the address bytes from the input pin (SI). On
the low-to-high transition of the CS pin, the data bytes in the selected Main Memory Page will be compared with the data
bytes in the Buffer. During the compare time (t
COMP
), the RDY/BUSY bit in the Status Register will indicate that the part is
busy. On completion of the compare operation, bit 6 of the Status Register will be updated with the result of the compare.
9.3 Auto Page Rewrite
This command only needs to be used if the possibility exists that static (non-changing) data may be stored in a page or
pages of a sector and the other pages of the same sector are erased and programmed a large number of times.
Applications that modify data in a random fashion within a sector may fall into this category. To preserve data integrity of
a sector, each page within a sector must be updated/rewritten at least once within every 50,000 cumulative page
erase/program operations within that sector. The Auto Page Rewrite command provides a simple and efficient method to
“refresh” a page in the main memory array in a single operation.
The Auto Page Rewrite command is a combination of the Main Memory Page to Buffer Transfer and Buffer to Main
Memory Page Program with Built-In Erase commands. With the Auto Page Rewrite command, a page of data is first
transferred from the main memory to the Buffer and then the same data is programmed back into the same page of main
memory, essentially “refreshing” the contents of that page. To start the Auto Page Rewrite operation with the optional
DataFlash-L page size (264 bytes), a 1-byte opcode, 58h must be clocked into the device followed by three address
bytes comprised of five dummy bits, 10 page address bits (PA9-PA0) that specify the page in main memory to be
rewritten, and nine dummy bits.
To initiate an Auto Page Rewrite with the a default page size (256 bytes), the opcode 58h must be clocked into the device
followed by three address bytes consisting of six dummy bits, 10 page address bits (A17 - A8) that specify the page in the
main memory that is to be rewritten, and eight dummy bits. When a low-to-high transition occurs on the CS pin, the part
will first transfer data from the page in main memory to the Buffer and then program the data from the Buffer back into
same page of main memory. The operation is internally self-timed and should take place in a maximum time of t
EP
.
During this time, the RDY/BUSY Status Register will indicate that the part is busy.
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If a sector is programmed or reprogrammed sequentially page by page and the possibility does not exist that there will be
a page or pages of static data, then the programming algorithm shown in Figure 26-1 on page 56 is recommended;
otherwise, if there is a chance that there may be a page or pages of a sector that will contain static data, then the
programming algorithm shown in Figure 26-2 on page 57 is recommended.
Please contact Adesto for availability of devices that are specified to exceed the 50,000 cycle cumulative limit.
Note: The Auto Page Rewrite command uses the same opcodes as the Read-Modify-Write command. If data bytes
are clocked into the device, then the device will perform a Read-Modify-Write operation. See the Read-Modify-
Write command description on page 15 for more details.
9.4 Status Register Read
The 2-byte Status Register can be used to determine the device's ready/busy status, page size, a Main Memory Page to
Buffer Compare operation result, the sector protection status, erase/program error status, and the device density. The
Status Register can be read at any time, including during an internally self-timed program or erase operation.
To read the Status Register, the CS pin must first be asserted and then the opcode D7h must be clocked into the device.
After the opcode has been clocked in, the device will begin outputting Status Register data on the SO pin during every
subsequent clock cycle. After the second byte of the Status Register has been clocked out, the sequence will repeat
itself, starting again with the first byte of the Status Register, as long as the CS pin remains asserted and the clock pin is
being pulsed. The data in the Status Register is constantly being updated, so each repeating sequence may output new
data. The RDY/BUSY status is available for both bytes of the Status Register and is updated for each byte.
Deasserting the CS pin will terminate the Status Register Read operation and put the SO pin into a high-impedance
state. The CS pin can be deasserted at any time and does not require that a full byte of data be read.
Table 9-1. Status Register Format – Byte 1
Note: 1. R = Readable only
Bit Name
Type
(1)
Description
7 RDY/BUSY Ready/Busy Status R
0 Device is busy with an internal operation.
1 Device is ready.
6 COMP Compare Result R
0 Main memory page data matches buffer data.
1 Main memory page data does not match buffer data.
5:2 DENSITY Density Code R 0101 2-Mbit
1 PROTECT Sector Protection
Status R
0 Sector protection is disabled.
1 Sector protection is enabled.
0 PAGE SIZE Page Size
Configuration R
0Device is configured for optional DataFlash-L page size (264
bytes).
1 Device is configured for default page size (256 bytes).
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Table 9-2. Status Register Format – Byte 2
Note: 1. R = Readable only
2. x = Don’t care. Can be “0” or “1”.
9.4.1 RDY/BUSY Bit
The RDY/BUSY bit is used to determine whether or not an internal operation, such as a program or erase, is in progress.
To poll the RDY/BUSY bit to detect the completion of an internally timed operation, new Status Register data must be
continually clocked out of the device until the state of the RDY/BUSY bit changes from a Logic 0 to a Logic 1 to indicate
completion.
9.4.2 COMP Bit
The result of the most recent Main Memory Page to Buffer Compare operation is indicated using the COMP bit. If the
COMP bit is a Logic 1, then at least one bit of the data in the Main Memory Page does not match the data in the Buffer.
9.4.3 DENSITY Bits
The device density is indicated using the DENSITY bits. For the AT25PE20, the four bit binary value is 0101. The
decimal value of these four binary bits does not actually equate to the device density; the four bits represent a
combinational code relating to differing densities of DataFlash-L devices. The DENSITY bits are not the same as the
density code indicated in the JEDEC Device ID information. The DENSITY bits are provided only for backward
compatibility to older generation DataFlash-L devices.
9.4.4 PROTECT Bit
The PROTECT bit provides information to the user on whether or not the sector protection has been enabled or disabled,
either by the software-controlled method or the hardware-controlled method.
9.4.5 PAGE SIZE Bit
The PAGE SIZE bit indicates whether the Buffer size and the page size of the main memory array is configured for the
default page size (256 bytes) or the optional DataFlash-L page size (264 bytes).
Bit Name
Type
(1)
Description
7 RDY/BUSY Ready/Busy Status R
0 Device is busy with an internal operation.
1 Device is ready.
6 RES Reserved for Future Use R x Reserved for future use.
5 EPE Erase/Program Error R
0 Erase or program operation was successful.
1 Erase or program error detected.
4 RES Reserved for Future Use R x Reserved for future use.
3 RES Reserved for Future Use R x Reserved for future use.
2 RES Reserved for Future Use R x Reserved for future use.
1 RES Reserved for Future Use R x Reserved for future use.
0 RES Reserved for Future Use R x Reserved for future use.
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9.4.6 EPE Bit
The EPE bit indicates whether the last erase or program operation completed successfully or not. If at least one byte
during the erase or program operation did not erase or program properly, then the EPE bit will be set to the Logic 1 state.
The EPE bit will not be set if an erase or program operation aborts for any reason, such as an attempt to erase or
program a protected region. The EPE bit is updated after every erase and program operation.
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10. Deep Power-Down
During normal operation, the device will be placed in the standby mode to consume less power as long as the CS pin
remains deasserted and no internal operation is in progress. The Deep Power-Down command offers the ability to place
the device into an even lower power consumption state called the Deep Power-Down mode.
When the device is in the Deep Power-Down mode, all commands including the Status Register Read command will be
ignored with the exception of the Resume from Deep Power-Down command. Since all commands will be ignored, the
mode can be used as an extra protection mechanism against program and erase operations.
Entering the Deep Power-Down mode is accomplished by simply asserting the CS pin, clocking in the opcode B9h, and
then deasserting the CS pin. Any additional data clocked into the device after the opcode will be ignored. When the CS
pin is deasserted, the device will enter the Deep Power-Down mode within the maximum time of t
EDPD
.
The complete opcode must be clocked in before the CS pin is deasserted; otherwise, the device will abort the operation
and return to the standby mode once the CS pin is deasserted. In addition, the device will default to the standby mode
after a power cycle.
The Deep Power-Down command will be ignored if an internally self-timed operation such as a program or erase cycle is
in progress. The Deep Power-Down command must be reissued after the internally self-timed operation has been
completed in order for the device to enter the Deep Power-Down mode.
Figure 10-1. Deep Power-Down
SCK
CS
SI
SO
MSB
I
CC
2 310
1 0 1 1 1 0 0 1
6 754
OPCODE
HIGH-IMPEDANCE
Standby Mode Current
Active Current
Deep Power-Down Mode Current
tEDPD
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10.1 Resume from Deep Power-Down
In order to exit the Deep Power-Down mode and resume normal device operation, the Resume from Deep Power-Down
command must be issued. The Resume from Deep Power-Down command is the only command that the device will
recognize while in the Deep Power-Down mode.
To resume from the Deep Power-Down mode, the CS pin must first be asserted and then the opcode ABh must be
clocked into the device. Any additional data clocked into the device after the opcode will be ignored. When the CS pin is
deasserted, the device will exit the Deep Power-Down mode and return to the standby mode within the maximum time of
t
RDPD
. After the device has returned to the standby mode, normal command operations such as Continuous Array Read
can be resumed.
If the complete opcode is not clocked in before the CS pin is deasserted, then the device will abort the operation and
return to the Deep Power-Down mode.
Figure 10-2. Resume from Deep Power-Down
SCK
CS
SI
SO
MSB
ICC
2 310
1 0 1 0 1 0 1 1
6 754
Opcode
High-impedance
Deep Power-Down Mode Current
Active Current
Standby Mode Current
tRDPD
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10.2 Ultra-Deep Power-Down
The Ultra-Deep Power-Down mode allows the device to consume far less power compared to the standby and Deep
Power-Down modes by shutting down additional internal circuitry. Since almost all active circuitry is shut down in this
mode to conserve power, the contents of the Buffer cannot be maintained. Therefore, any data stored in the Buffer will be
lost once the device enters the Ultra-Deep Power-Down mode.
When the device is in the Ultra-Deep Power-Down mode, all commands including the Status Register Read and Resume
from Deep Power-Down commands will be ignored. Since all commands will be ignored, the mode can be used as an
extra protection mechanism against program and erase operations.
Entering the Ultra-Deep Power-Down mode is accomplished by simply asserting the CS pin, clocking in the opcode 79h,
and then deasserting the CS pin. Any additional data clocked into the device after the opcode will be ignored. When the
CS pin is deasserted, the device will enter the Ultra-Deep Power-Down mode within the maximum time of t
EUDPD
.
The complete opcode must be clocked in before the CS pin is deasserted; otherwise, the device will abort the operation
and return to the standby mode once the CS pin is deasserted. In addition, the device will default to the standby mode
after a power cycle.
The Ultra-Deep Power-Down command will be ignored if an internally self-timed operation such as a program or erase
cycle is in progress. The Ultra-Deep Power-Down command must be reissued after the internally self-timed operation
has been completed in order for the device to enter the Ultra-Deep Power-Down mode.
Figure 10-3. Ultra-Deep Power-Down
SCK
CS
SI
SO
MSB
ICC
2 310
0
6 754
Opcode
High-impedance
Ultra-Deep Power-Down Mode Current
Active Current
Standby Mode Current
tEUDPD
1 1 1 1 0 0 1
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10.2.1 Exit Ultra-Deep Power-Down
To exit from the Ultra-Deep Power-Down mode, the CS pin must simply be pulsed by asserting the CS pin, waiting the
minimum necessary t
CSLU
time, and then deasserting the CS pin again. To facilitate simple software development, a
dummy byte opcode can also be entered while the CS pin is being pulsed; the dummy byte opcode is simply ignored by
the device in this case. After the CS pin has been deasserted, the device will exit from the Ultra-Deep Power-Down mode
and return to the standby mode within a maximum time of t
XUDPD
. If the CS pin is reasserted before the t
XUDPD
time has
elapsed in an attempt to start a new operation, then that operation will be ignored and nothing will be performed. The
system must wait for the device to return to the standby mode before normal command operations such as Continuous
Array Read can be resumed.
Since the contents of the Buffer cannot be maintained while in the Ultra-Deep Power-Down mode, the Buffer will contain
undefined data when the device returns to the standby mode.
Figure 10-4. Exit Ultra-Deep Power-Down
CS
SO
ICC
High-impedance
Ultra-Deep Power-Down Mode Current
Active Current
Standby Mode Current
tXUDPD
tCSLU
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11. Buffer and Page Size Configuration
The memory array of DataFlash-L devices is actually larger than other Serial Flash devices in that extra user-accessible
bytes are provided in each page of the memory array. For the AT25PE20, there are an extra eight bytes of memory in
each page for a total of an extra 8KB (64-Kbits) of user-accessible memory.
Some applications, however, may not want to take advantage of this extra memory and instead architect their software to
operate on a binary, logical addressing scheme. To allow this, the DataFlash-L can be configured so that the Buffer and
page sizes are 256 bytes instead of the optional 264 bytes. In addition, the configuration of the Buffer and page sizes is
reversible and can be changed from 264 bytes to 256 bytes or from 256 bytes to 264 bytes. The configured setting is
stored in an internal nonvolatile register so that the Buffer and page size configuration is not affected by power cycles.
The nonvolatile register has a limit of 10,000 erase/program cycles; therefore, care should be taken to not switch
between the size options more than 10,000 times.
Devices are initially shipped from Adesto with the Buffer and page sizes set to 256 bytes. To configure the device for
default page size (256 bytes), a 4-byte opcode sequence of 3Dh, 2Ah, 80h, and A6h must be clocked into the device.
After the last bit of the opcode sequence has been clocked in, the CS pin must be deasserted to initiate the internally self-
timed configuration process and nonvolatile register program cycle. The programming of the nonvolatile register should
take place in a time of t
EP
, during which time, the RDY/BUSY bit in the Status Register will indicate that the device is
busy. The device does not need to be power cycled after the completion of the configuration process and register
program cycle in order for the Buffer and page size to be configured to 256 bytes.
To configure the device for optional DataFlash-L page size (264 bytes), a 4-byte opcode sequence of 3Dh, 2Ah, 80h, and
A7h must be clocked into the device. After the last bit of the opcode sequence has been clocked in, the CS pin must be
deasserted to initial the internally self-timed configuration process and nonvolatile register program cycle. The
programming of the nonvolatile register should take place in a time of t
EP
, during which time, the RDY/BUSY bit in the
Status Register will indicate that the device is busy. The device does not need to be power cycled after the completion of
the configuration process and register program cycle in order for the Buffer and page size to be configured to 264 bytes.
Table 11-1. Buffer and Page Size Configuration Commands
Figure 11-1. Buffer and Page Size Configuration
Command Byte 1 Byte 2 Byte 3 Byte 4
Default DataFlash-L page size (256 bytes) 3Dh 2Ah 80h A6h
Optional DataFlash-L page size (264 bytes) 3Dh 2Ah 80h A7h
CS
SI 3Dh 2Ah 80h Opcode
Byte 4
Each transition represents eight bits
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12. Manufacturer and Device ID Read
Identification information can be read from the device to enable systems to electronically query and identify the device
while it is in the system. The identification method and the command opcode comply with the JEDEC Standard for
“Manufacturer and Device ID Read Methodology for SPI Compatible Serial Interface Memory Devices”. The type of
information that can be read from the device includes the JEDEC-defined Manufacturer ID, the vendor-specific
Device ID, and the vendor-specific Extended Device Information.
The Read Manufacturer and Device ID command is limited to a maximum clock frequency of f
CLK
. Since not all Flash
devices are capable of operating at very high clock frequencies, applications should be designed to read the
identification information from the devices at a reasonably low clock frequency to ensure that all devices to be used in the
application can be identified properly. Once the identification process is complete, the application can then increase the
clock frequency to accommodate specific Flash devices that are capable of operating at the higher clock frequencies.
To read the identification information, the CS pin must first be asserted, and then the opcode 9Fh must be clocked into
the device. After the opcode has been clocked in, the device will begin outputting the identification data on the SO pin
during the subsequent clock cycles. The first byte to be output will be the Manufacturer ID, followed by two bytes of the
Device ID information. The fourth byte output will be the Extended Device Information (EDI) String Length, which will be
01h, indicating that one byte of EDI data follows. After the one byte of EDI data is output, the SO pin will go into a
high-impedance state; therefore, additional clock cycles will have no affect on the SO pin and no data will be output. As
indicated in the JEDEC Standard, reading the EDI String Length and any subsequent data is optional.
Deasserting the CS pin will terminate the Manufacturer and Device ID Read operation and put the SO pin into a
high-impedance state. The CS pin can be deasserted at any time and does not require that a full byte of data be read.
Table 12-1. Manufacturer and Device ID Information
Byte No. Data Type Value
1 Manufacturer ID 1Fh
2 Device ID (Byte 1) 23h
3 Device ID (Byte 2) 00h
4 Extended Device Information (EDI) String Length 01h
5 [Optional to Read] EDI Byte 1 00h
Table 12-2. Manufacturer and Device ID Details
Data Type Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Hex
Value Details
Manufacturer ID
JEDEC Assigned Code
1Fh JEDEC code: 0001 1111 (1Fh for Adesto)
0 0 0 1 1 1 1 1
Device ID (Byte 1)
Family Code Density Code
23h Family code: 001 (AT45Dxxx Family)
Density code: 00011 (2-Mbit)
0 0 1 0 0 0 1 1
Device ID (Byte 2)
Sub Code Product Variant
00h Sub code: 000 (Standard Series)
Product variant:00000
0 0 0 0 0 0 0 0
32AT25PE20
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Figure 12-1. Read Manufacturer and Device ID
Table 12-3. EDI Data
Byte Number Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Hex
Value Details
5
RFU Device Revision
00h RFU: Reserved for Future Use
Device revision:00000 (Initial Version)
00000000
SCK
CS
SI
SO
60
9Fh
87 47
Opcode
1Fh 00h 01h 00h
Manufacturer ID Device ID
Byte 1
Device ID
Byte 2
EDI
String Length
EDI
Data Byte 1
High-impedance
14 1615 22 2423 38 403930 3231
Note: Each transition shown for SI and SO represents one byte (eight bits)
23h
33AT25PE20
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13. Software Reset
In some applications, it may be necessary to prematurely terminate a program or erase cycle early rather than wait the
hundreds of microseconds or milliseconds necessary for the program or erase operation to complete normally. The
Software Reset command allows a program or erase operation in progress to be ended abruptly and returns the device
to an idle state.
To perform a Software Reset, the CS pin must be asserted and a 4-byte command sequence of F0h, 00h, 00h, and 00h
must be clocked into the device. Any additional data clocked into the device after the last byte will be ignored. When the
CS pin is deasserted, the program or erase operation currently in progress will be terminated within a time t
SWRST
. Since
the program or erase operation may not complete before the device is reset, the contents of the page being programmed
or erased cannot be guaranteed to be valid.
The Software Reset command has no effect on the states of the Sector Protection Register or the Buffer and page size
configuration.
The complete 4-byte opcode must be clocked into the device before the CS pin is deasserted; otherwise, no reset
operation will be performed.
Table 13-1. Software Reset
Figure 13-1. Software Reset
Command Byte 1 Byte 2 Byte 3 Byte 4
Software Reset F0h 00h 00h 00h
CS
SI F0h 00h 00h 00h
Each transition represents eight bits
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14. Operation Mode Summary
The commands described previously can be grouped into four different categories to better describe which commands
can be executed at what times.
Group A commands consist of:
1. Main Memory Page Read
2. Continuous Array Read (SPI)
3. Read Sector Protection Register
4. Read Security Register
5. Buffer Read
Group B commands consist of:
1. Page Erase
2. Block Erase
3. Sector Erase
4. Chip Erase
5. Main Memory Page to the Buffer Transfer
6. Main Memory Page to the Buffer Compare
7. Buffer to Main Memory Page Program with Built-In Erase
8. Buffer to Main Memory Page Program without Built-In Erase
9. Main Memory Page Program through the Buffer with Built-In Erase
10. Main Memory Byte/Page Program through Buffer without Built-In Erase
11. Auto Page Rewrite
12. Read-Modify-Write
Group C commands consist of:
1. Buffer Write
2. Status Register Read
3. Manufacturer and Device ID Read
Group D commands consist of:
1. Erase Sector Protection Register
2. Program Sector Protection Register
3. Buffer and Page Size Configuration
If a Group A command is in progress (not fully completed), then another command in Group A, B, C, or D should not be
started. However, during the internally self-timed portion of Group B commands, any command in Group C can be
executed. The Group B commands using the Buffer should use Group C commands. Finally, during the internally
self-timed portion of a Group D command, only the Status Register Read command should be executed.
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15. Command Tables
Table 15-1. Read Commands
Table 15-2. Program and Erase Commands
Command Opcode
Main Memory Page Read D2h
Continuous Array Read (Low Power Mode) 01h
Continuous Array Read (Low Frequency) 03h
Continuous Array Read (High Frequency) 0Bh
Continuous Array Read (Legacy Command – Not Recommended for New Designs) E8h
Buffer Read (Low Frequency) D1h
Buffer Read (High Frequency) D4h
Command Opcode
Buffer Write 84h
Buffer to Main Memory Page Program with Built-In Erase 83h
Buffer to Main Memory Page Program without Built-In Erase 88h
Main Memory Page Program through Buffer with Built-In Erase 82h
Main Memory Byte/Page Program through Buffer without Built-In Erase 02h
Page Erase 81h
Block Erase 50h
Sector Erase 7Ch
Chip Erase C7h + 94h + 80h + 9Ah
Read-Modify-Write through Buffer 1 58h
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Table 15-3. Protection and Security Commands
Table 15-4. Additional Commands
Table 15-5. Legacy Commands
(1)
Note: 1. Legacy commands are not recommended for new designs.
Command Opcode
Enable Sector Protection 3Dh + 2Ah + 7Fh + A9h
Disable Sector Protection 3Dh + 2Ah + 7Fh + 9Ah
Erase Sector Protection Register 3Dh + 2Ah + 7Fh + CFh
Program Sector Protection Register 3Dh + 2Ah + 7Fh + FCh
Read Sector Protection Register 32h
Read Security Register 77h
Command Opcode
Main Memory Page to Buffer Transfer 53h
Main Memory Page to Buffer Compare 60h
Auto Page Rewrite 58h
Deep Power-Down B9h
Resume from Deep Power-Down ABh
Ultra-Deep Power-Down 79h
Status Register Read D7h
Manufacturer and Device ID Read 9Fh
Configure Default 256 Byte Page Size 3Dh + 2Ah + 80h + A6h
Configure Optional 264 Byte DataFlash-L Page Size 3Dh + 2Ah + 80h + A7h
Software Reset F0h + 00h + 00h + 00h
Command Opcode
Buffer Read 54H
Main Memory Page Read 52H
Continuous Array Read 68H
Status Register Read 57H
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Table 15-6. Detailed Bit-level Addressing Sequence for Default Page Size (256 bytes)
Note: X = Dummy Bit
Page Size = 256-bytes Address Byte Address Byte Address Byte
Additional
Dummy
BytesOpcode Opcode
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
A17
A16
A15
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
01h
0 0 00 0 0 01XXXXXXAAAAAAAAAAAAAAAAAA
N/A
02h
0 0 00 0 0 10XXXXXXAAAAAAAAAAAAAAAAAA
N/A
03h
0 0 00 0 0 11XXXXXXAAAAAAAAAAAAAAAAAA
N/A
0Bh
0 0 00 1 0 11XXXXXXAAAAAAAAAAAAAAAAAA
1
1Bh
0 0 01 1 0 11XXXXXXAAAAAAAAAAAAAAAAAA
2
32h
0 0 11 0 0 10XXXXXXXXXXXXXXXXXXXXXXXX
N/A
50h
0 1 01 0 0 00XXXXXXAAAAAAAXXXXXXXXXXX
N/A
53h
0 1 01 0 0 11XXXXXXAAAAAAAAAAXXXXXXXX
N/A
58h
(1)
1. Shown to indicate when Auto Page Rewrite Operation is executed.
0 1 01 1 0 00XXXXXXAAAAAAAAAAXXXXXXXX
N/A
58h
(2)
2. Shown to indicate when Read Modify Write Operation is executed.
0 1 01 1 0 00XXXXXXAAAAAAAAAAAAAAAAAA
N/A
60h
0 1 10 0 0 00XXXXXXAAAAAAAAAAXXXXXXXX
N/A
77h
0 1 11 0 1 11XXXXXXXXXXXXXXXXXXXXXXXX
N/A
79h
0 1 1 1 1 0 0 1 N/A N/A N/A
N/A
7Ch
0 1 11 1 1 00XXXXXXAAAXXXXXXXXXXXXXXX
N/A
81h
1 0 00 0 0 01XXXXXXAAAAAAAAAAXXXXXXXX
N/A
82h
1 0 00 0 0 10XXXXXXAAAAAAAAAAAAAAAAAA
N/A
83h
1 0 00 0 0 11XXXXXXAAAAAAAAAAXXXXXXXX
N/A
84h
1 0 00 0 1 00XXXXXXXXXXXXXXXXAAAAAAAA
N/A
88h
1 0 00 1 0 00XXXXXXAAAAAAAAAAXXXXXXXX
N/A
9Fh
1 0 0 1 1 1 1 1 N/A N/A N/A
N/A
B9h
1 0 1 1 1 0 0 1 N/A N/A N/A
N/A
ABh
1 0 1 0 1 0 1 1 N/A N/A N/A
N/A
D1h
1 1 01 0 0 01XXXXXXXXXXXXXXXXAAAAAAAA
N/A
D2h
1 1 01 0 0 10XXXXXXAAAAAAAAAAAAAAAAAA
4
D4h
1 1 01 0 1 00XXXXXXXXXXXXXXXXAAAAAAAA
1
D7h
1 1 0 1 0 1 1 1 N/A N/A N/A
N/A
E8h
1 1 10 1 0 00XXXXXXAAAAAAAAAAAAAAAAAA
4
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Table 15-7. Detailed Bit-level Addressing Sequence for Optional Page Size (264 bytes)
Note: P = Page Address Bit B = Byte/Buffer Address Bit X = Dummy Bit
Page Size = 264-bytes Address Byte Address Byte Address Byte
Additional
Dummy
BytesOpcode Opcode
Reserved
Reserved
Reserved
Reserved
Reserved
PA9
PA8
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
BA8
BA7
BA6
BA5
BA4
BA3
BA2
BA1
BA0
01h
0 0 0 0 0 0 0 1 X X X X X P P P P P P P P P P B B B B B B B B B
N/A
02h
0 0 0 0 0 0 1 0 X X X X X P P P P P P P P P P B B B B B B B B B
N/A
03h
0 0 0 0 0 0 1 1 X X X X X P P P P P P P P P P B B B B B B B B B
N/A
0Bh
0 0 0 0 1 0 1 1 X X X X X P P P P P P P P P P B B B B B B B B B
1
1Bh
0 0 0 1 1 0 1 1 X X X X X P P P P P P P P P P B B B B B B B B B
2
32h
0 0 1 1 0 0 1 0 X X X X X X X X X X X X X X X X X X X X X X X X
N/A
50h
0 1 0 1 0 0 0 0 X X X X X P P P P P P P X X X X X X X X X X X X
N/A
53h
0 1 0 1 0 0 1 1 X X X X X P P P P P P P P P P X X X X X X X X X
N/A
58h
(1)
1. Shown to indicate when Auto Page Rewrite Operation is executed.
0 1 0 1 1 0 0 0 X X X X X P P P P P P P P P P X X X X X X X X X
N/A
58h
(2)
2. Shown to indicate when Read Moodify Write Operation is executed.
0 1 0 1 1 0 0 0 X X X X X P P P P P P P P P P B B B B B B B B B
N/A
60h
0 1 1 0 0 0 0 0 X X X X X P P P P P P P P P X X X X X X X X X X
N/A
77h
0 1 1 1 0 1 1 1 X X X X X X X X X X X X X X X X X X X X X X X X
N/A
79h
0 1 1 1 1 0 0 1 N/A N/A N/A
N/A
7Ch
0 1 1 1 1 1 0 0 X X X X X P P P X X X X X X X X X X X X X X X X
N/A
81h
1 0 0 0 0 0 0 1 X X X X X P P P P P P P P P P X X X X X X X X X
N/A
82h
1 0 0 0 0 0 1 0 X X X X X P P P P P P P P P P B B B B B B B B B
N/A
83h
1 0 0 0 0 0 1 1 X X X X X P P P P P P P P P P X X X X X X X X X
N/A
84h
1 0 0 0 0 1 0 0 X X X X X X X X X X X X X X X B B B B B B B B B
N/A
88h
1 0 0 0 1 0 0 0 X X X X X P P P P P P P P P P X X X X X X X X X
N/A
9Fh
1 0 0 1 1 1 1 1 N/A N/A N/A
N/A
B9h
1 0 1 1 1 0 0 1 N/A N/A N/A
N/A
ABh
1 0 1 0 1 0 1 1 N/A N/A N/A
N/A
D1h
1 1 0 1 0 0 0 1 X X X X X X X X X X X X X X X B B B B B B B B B
N/A
D2h
1 1 0 1 0 0 1 0 X X X X X P P P P P P P P P P B B B B B B B B B
4
D4h
1 1 0 1 0 1 0 0 X X X X X X X X X X X X X X X B B B B B B B B B
1
D7h
1 1 0 1 0 1 1 1 N/A N/A N/A
N/A
E8h
1 1 1 0 1 0 0 0 X X X X X P P P P P P P P P P B B B B B B B B B
4
39AT25PE20
DS-25PE20–139C–8/2018
16. Power-On/Reset State
When power is first applied to the device, or when recovering from a reset condition, the output pin (SO) will be in a high
impedance state, and a high-to-low transition on the CSB pin will be required to start a valid instruction. The SPI mode
(Mode 3 or Mode 0) will be automatically selected on every falling edge of CSB by sampling the inactive clock state.
16.1 Power-Up/Power-Down Voltage and Timing Requirements
As the device initializes, there will be a transient current demand. The system needs to be capable of providing this
current to ensure correct initialization. During power-up, the device must not be accessed for at least the minimum t
VCSL
time after the supply voltage reaches the minimum V
CC
level. While the device is being powered-up, the internal Power-
On Reset (POR) circuitry keeps the device in a reset mode until the supply voltage rises above the maximum POR
threshold value (V
POR
). During this time, all operations are disabled and the device will not respond to any commands.
After power-up, the device will be in the standby mode.
If the first operation to the device after power-up will be a program or erase operation, then the operation cannot be
started until the supply voltage reaches the minimum V
CC
level and an internal device delay has elapsed. This delay will
be a maximum time of t
PUW
.
Table 16-1. Voltage and Timing Requirements for Power-Up/Power-Down
Figure 16-1. Power-Up Timing
Symbol Parameter Min Max Units
V
PWD
(1)
1. Not 100% tested (value guaranteed by design and characterization).
V
CC
for device initialization 1.0 V
t
PWD
(1)
Minimum duration for device initialization 300 µs
t
VCSL
Minimum V
CC
to chip select low time for Read command 70 µs
t
VR
(1)
V
CC
rise time 1 500000 µs/V
V
POR
Power on reset voltage 1.45 1.6 V
t
PUW
Power up delay time before Program or Erase is allowed 3 ms
VCC
VPOR max
Max VPWD
Time
tPWD
tPUW Full Operation Permitted
tVR
tVCSL
Read Operation
Permitted
VCC min
V
POR
max
V
PWD
max
40AT25PE20
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17. System Considerations
The serial interface is controlled by the Serial Clock (SCK), Serial Input (SI), and Chip Select (CS) pins. These signals
must rise and fall monotonically and be free from noise. Excessive noise or ringing on these pins can be misinterpreted
as multiple edges and will cause improper operation of the device. PCB traces must be kept to a minimum distance or
appropriately terminated to ensure proper operation. If necessary, decoupling capacitors can be added on these pins to
provide filtering against noise glitches.
As system complexity continues to increase, voltage regulation is becoming more important. A key element of any
voltage regulation scheme is its current sourcing capability. Like all Flash memories, the peak current for DataFlash-L
devices occurs during the programming and erasing operations. The supply voltage regulator needs to be able to supply
this peak current requirement. An under specified regulator can cause current starvation. Besides increasing system
noise, current starvation during programming or erasing can lead to improper operation and possible data corruption.
41AT25PE20
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18. Electrical Specifications
18.1 Absolute Maximum Ratings*
18.2 DC and AC Operating Range
Temperature under Bias . . . . . . . -55°C to +125°C
*Notice: Stresses beyond those listed under “Absolute
Maximum Ratings” may cause permanent
damage to the device. This is a stress rating only
and functional operation of the device at these or
any other conditions beyond those indicated in
the operational sections of this specification is not
implied. Exposure to absolute maximum rating
conditions for extended periods may affect device
reliability.Voltage extremes referenced in the
“Absolute Maximum Ratings” are intended to
accommodate short duration
undershoot/overshoot conditions and does not
imply or guarantee functional device operation at
these levels for any extended period of time.
Storage Temperature. . . . . . . . . . -65°C to +150°C
Absolute Maximum V
cc
. . . . . . . . . . . . . . . . .3.96V
All Output Voltages with Respect to Ground
. . . . . . . . -0.6V to 4.2V (Max V
CC
of 3.6V + 0.6V)
All Input Voltages with Respect to Ground
(excluding V
CC
pin, including NC pins)
. . . . . . . . -0.6V to 4.2V (Max V
CC
of 3.6V + 0.6V)
AT25PE20
Operating Temperature (Case) Industrial -40°C to 85°C
V
CC
Power Supply 1.65V to 3.6V
42AT25PE20
DS-25PE20–139C–8/2018
18.3 DC Characteristics
Notes: 1. Typical values measured at 1.8V @ 25
°C
for the 1.65V to 3.6V range.
2. Typical values measured at 3.0V @ 25
°C
for the 2.3V to 3.6V range.
3. All inputs (SI, SCK, CS, WP, and RESET) are guaranteed by design to be 5V toleran
t.
18.4 AC Characteristics
Symbol Parameter Condition
(3)
1.65V to 3.6V 2.3V to 3.6V
UnitsMin Typ Max Min Typ Max
I
UDPD
Ultra-Deep Power-
Down Current
CS= V
CC
. All other inputs at
0V or V
CC
0.5 2 0.4 2 µA
I
DPD
Deep Power-Down
Current
CS= V
CC
. All other inputs at
0V or V
CC
6 12 8 12 µA
I
SB
Standby Current CS= V
CC
. All other inputs at
0V or V
CC
25 40 25 40 µA
I
CC1
(1)(2)
Active Current, Low
Power Read (01h)
Operation
f = 1MHz; I
OUT
= 0mA 6 9 6 9 mA
f = 15MHz; I
OUT
= 0mA 7 10 7 10 mA
I
CC2
(1)(2)
Active Current,
Read Operation
f = 50MHz; I
OUT
= 0mA 10 12 10 12 mA
f = 85MHz; I
OUT
= 0mA 12 15 12 15 mA
I
CC3
(1)(2)
Active Current,
Program Operation CS = V
CC
10 12 10 12 mA
I
CC4
(1)(2)
Active Current,
Erase Operation CS = V
CC
8 12 8 12 mA
I
LI
Input Load Current All inputs at CMOS levels 1 1 µA
I
LO
Output Leakage
Current All inputs at CMOS levels 1 1 µA
V
IL
Input Low Voltage V
CC
x
0.2
V
CC
x
0.3 V
V
IH
Input High Voltage V
CC
x
0.8
V
CC
x
0.7 V
V
OL
Output Low Voltage I
OL
= 100µA 0.2 0.4 V
V
OH
Output High
Voltage I
OH
= -100µA V
CC
-
0.2V
V
CC
-
0.2V V
Symbol Parameter
1.65V to 3.6V 2.3V to 3.6V
Min Typ Max Min Typ Max Units
f
SCK
SCK Frequency 70 70 MHz
f
CAR1
SCK Frequency for Continuous Read 70 85 MHz
f
CAR2
SCK Frequency for Continuous Read
(Low Frequency) 33 33 MHz
43AT25PE20
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Note: 1. Values are based on device characterization, not 100% tested in production.
f
CAR3
SCK Frequency for Continuous Read
(Low Power Mode – 01h Opcode) 15 15 MHz
t
WH
SCK High Time 4 4 ns
t
WL
SCK Low Time 4 4 ns
t
SCKR
(1)
SCK Rise Time, Peak-to-peak 0.1 0.1 V/ns
t
SCKF(1)
SCK Fall Time, Peak-to-peak 0.1 0.1 V/ns
t
CS
Minimum CS High Time 20 20 ns
t
CSS
CS Setup Time 6 5 ns
t
CSH
CS Hold Time 5 5 ns
t
SU
Data In Setup Time 2 2 ns
t
H
Data In Hold Time 1 1 ns
t
HO
Output Hold Time 0 0 ns
t
DIS
(1)
Output Disable Time 8 6 ns
t
V
Output Valid 7 6 ns
t
WPE
WP Low to Protection Enabled 1 1 µs
t
WPD
WP High to Protection Disabled 1 1 µs
t
EUDPD
(1)
CS High to Ultra-Deep Power-Down 3 3 µs
t
CSLU
Minimum CS Low Time to Exit Ultra-Deep
Power-Down 20 20 ns
t
XUDPD
Exit Ultra-Deep Power-Down Time 240 120 µs
t
EDPD
(1)
CS High to Deep Power-Down 2 2 µs
t
RDPD
Resume from Deep Power-Down Time 35 35 µs
t
XFR
Page to Buffer Transfer Time 100 100 µs
t
COMP
Page to Buffer Compare Time 100 100 µs
t
RST
RESET Pulse Width 10 10 µs
t
REC
RESET Recovery Time 1 1 µs
t
SWRST
Software Reset Time 35 35 µs
Symbol Parameter
1.65V to 3.6V 2.3V to 3.6V
Min Typ Max Min Typ Max Units
44AT25PE20
DS-25PE20–139C–8/2018
18.5 Program and Erase Characteristics
19. Input Test Waveforms and Measurement Levels
20. Output Test Load
Symbol Parameter Typ Max Typ Max Units
t
EP
Page Erase and Programming Time (256/264
bytes) 10 35 10 25 ms
t
P
Page Programming Time 1.5 3 1.5 3 ms
t
BP
Byte Programming Time 8 8 µs
t
PE
Page Erase Time 6 25 6 25 ms
t
BE
Block Erase Time 25 35 25 35 ms
t
SE
Sector Erase Time 350 550 350 550 ms
t
CE
Chip Erase Time 3 4 3 4 s
AC
Driving
Levels
AC
Measurement
Level
0.1VCC
VCC/2
0.9VCC
tR, tF < 2ns (10% to 90%)
Device
Under
Test
30pF
45AT25PE20
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21. Utilizing the RapidS Function
To take advantage of the RapidS function’s ability to operate at higher clock frequencies, a full clock cycle must be used
to transmit data back and forth across the serial bus. The DataFlash-L is designed to always clock its data out on the
falling edge of the SCK signal and clock data in on the rising edge of SCK.
For full clock cycle operation to be achieved, when the DataFlash-L is clocking data out on the falling edge of SCK, the
host controller should wait until the next falling edge of SCK to latch the data in. Similarly, the host controller should clock
its data out on the rising edge of SCK in order to give the DataFlash-L a full clock cycle to latch the incoming data in on
the next rising edge of SCK.
Figure 21-1. RapidS Mode
SCK
MOSI
MISO
12 3 4 5 6 7 8 1 2 3 4 5 6 7 8
MOSI = Master Out, Slave In
MISO = Master In, Slave Out
The Master is the host controller and the Slave is the DataFlash.
The Master always clocks data out on the rising edge of SCK and always clocks data in on the falling edge of SCK.
The Slave always clocks data out on the falling edge of SCK and always clocks data in on the rising edge of SCK.
A. Master clocks out first bit of BYTE-MOSI on the rising edge of SCK
B. Slave clocks in first bit of BYTE-MOSI on the next rising edge of SCK
C. Master clocks out second bit of BYTE-MOSI on the same rising edge of SCK
D. Last bit of BYTE-MOSI is clocked out from the Master
E. Last bit of BYTE-MOSI is clocked into the slave
F. Slave clocks out first bit of BYTE-SO
G. Master clocks in first bit of BYTE-SO
H. Slave clocks out second bit of BYTE-SO
I. Master clocks in last bit of BYTE-SO
ABC D E
FG
1
H
BYTE-MOSI
MSB LSB
BYTE-SO
MSB LSB
Slave CS
I
46AT25PE20
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Figure 21-2. Command Sequence for Read/Write Operations for Page Size 256 bytes
(Except Status Register Read, Manufacturer and Device ID Read)
Figure 21-3. Command Sequence for Read/Write Operations for Page Size 264 bytes
(Except Status Register Read, Manufacturer and Device ID Read)
SI (Input) CMD 8-bits 8-bits 8-bits
Page Address
(A17 - A8)
X X X X X X X X X X X X X X X X LSB
X X X X X X X X
Byte/Buffer Address
(A7 - A0/BFA7 - BFA0)
MSB
6 Dummy
Bits
Page Address
(PA9 - PA0)
Byte/Buffer Address
(BA8 - BA0/BFA8 - BFA0)
SI (Input) CMD 8-bits 8-bits 8-bits
X X X X X X XX X X X X LSB
X X X X X X X X
MSB
5 Dummy
Bits
X X X X
47AT25PE20
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22. AC Waveforms
Four different timing waveforms are shown in Figure 22-1 through Figure 22-4. Waveform 1 shows the SCK signal being
low when CS makes a high-to-low transition, and Waveform 2 shows the SCK signal being high when CS makes a
high-to-low transition. In both cases, output SO becomes valid while the SCK signal is still low (SCK low time is specified
as t
WL
). Timing Waveforms 1 and 2 conform to RapidS serial interface but for frequencies only up to 70MHz.
Waveforms 1 and 2 are compatible with SPI Mode 0 and SPI Mode 3, respectively.
Waveform 3 and 4 illustrate general timing diagrams for RapidS serial interface. These are similar to Waveform 1 and 2,
except that output SO is not restricted to become valid during the t
WL
period. These timing waveforms are valid over the
full frequency range (maximum frequency = 70MHz) of the RapidS serial case.
Figure 22-1. Waveform 1 = SPI Mode 0 Compatible
Figure 22-2. Waveform 2 = SPI Mode 3 Compatible
CS
SCK
SI
SO
tCSS
Valid In
tH
tSU
tWH tWL tCSH
tCS
tV
High-impedance Valid Out
tHO tDIS
High-impedance
CS
SCK
SO
tCSS
Valid In
tH
tSU
tWL tWH tCSH
tCS
tV
High Z Valid Out
tHO tDIS
High-impedance
SI
1.65V to 3.6V 2.3V to 3.6V
48AT25PE20
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Figure 22-3. Waveform 3 = RapidS Mode 0
Figure 22-4. Waveform 4 = RapidS Mode 3
CS
SCK
SI
SO
tCSS
Valid In
tH
tSU
tWH tWL tCSH
tCS
tV
High-impedance Valid Out
tHO tDIS
High-impedance
CS
SCK
SO
tCSS
Valid In
tH
tSU
tWL tWH tCSH
tCS
tV
High Z Valid Out
tHO tDIS
High-impedance
SI
49AT25PE20
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23. Write Operations
The following block diagram and waveforms illustrate the various write sequences available.
Figure 23-1. Block Diagram
Figure 23-2. Buffer Write
Figure 23-3. Buffer to Main Memory Page Program
Flash Memory Array
I/O Interface
SI
Buffer To
Main Memory
Page Program
Buffer
Write
Page (256/264 bytes)
Buffer (256/264 bytes)
CS
SI (Input) CMD X X···X, BFA8 BFA7-0 n n + 1 Last Byte
Completes Writing into Selected Buffer
Default Page Size
16 Dummy Bits + BFA7-BFA0
CS
SI (Input) CMD PA9-7 PA6-0, X XXXX XXX
Starts Self-timed Erase/Program Operation
Binary Page Size
A17-A8 + 8 Dummy Bits
n = 1st byte read
n+1 = 2nd byte read
Each transition represents eight bits
50AT25PE20
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24. Read Operations
The following block diagram and waveforms illustrate the various read sequences available.
Figure 24-1. Block Diagram
Figure 24-2. Main Memory Page Read
Flash Memory Array
Page (256/264 bytes)
Buffer (256/264 bytes)
I/O Interface
Main Memory
Page To
Buffer
Main Memory
Page Read
Buffer
Read
SO
CS
SI (Input)
SO (Output) n
CMD PA8-7 PA6-0, BA8 BA7-0 X X
Address for Default Page Size
A16 A15-A8 A7-A0
n n + 1
4 Dummy Bytes
51AT25PE20
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Figure 24-3. Main Memory Page to Buffer Transfer
Data From the selected Flash Page is read into the Buffer
Figure 24-4. Buffer Read
CS
SI (Input) CMD PA6-0, X XXXX XXXX
Starts Reading Page Data into Buffer
Default Page Size
A17-A8 + 8 Dummy Bits
SO (Output)
X...X, PA9-7
CS
SI (Input)
SO (Output) n
CMD X X...X, BFA8 BFA7-0 X
Address for Default Page Size
16 Dummy Bits + BFA7-BFA0
n n + 1
No Dummy Byte (opcode D1h)
1 Dummy Byte (opcode D4h)
Each transition represents eight bits
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25. Detailed Bit-level Read Waveforms: RapidS Mode 0/Mode 3
Figure 25-1. Continuous Array Read (Legacy Opcode E8h)
Figure 25-2. Continuous Array Read (Opcode 0Bh)
Figure 25-3. Continuous Array Read (Opcode 01h or 03h)
SCK
CS
SI
SO
MSB MSB
2 3 1 0
1 1 1 0 1 0 0 0
6 7 5 4 10 11 9 8 12 63 66 67 65 64 62 33 34 31 32 29 30 68 71 72 70 69
Opcode
A A A A A A A A A
MSB
X X X X X X
MSB MSB
D D D D D D D D D D
Address Bits 32 Dummy Bits
Data Byte 1
High-impedance
SCK
CS
SI
SO
MSB MSB
2 3 1 0
0 0 0 0 1 0 1 1
6 7 5 4 10 11 9 8 12 39 42 43 41 40 38 33 34 31 32 29 30 44 47 48 46 45
Opcode
A A A A A A A A A
MSB
X X X X X X
MSB MSB
D D D D D D D D D D
Address Bits A17 - A0 Dummy Bits
Data Byte 1
High-impedance
36 37 35
X X
SCK
CS
SI
SO
MSB MSB
2 3 1 0
0 0 0 0 0 0 1 1
6 7 5 4 10 11 9 8 12 37 38 33 36 35 34 31 32 29 30 39 40
Opcode
A A A A A A A A A
MSB MSB
D D D D D D D D D D
Address Bits A17-A0
Data Byte 1
High-impedance
53AT25PE20
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Figure 25-4. Main Memory Page Read (Opcode D2h)
Figure 25-5. Buffer Read (Opcode D4h)
Figure 25-6. Buffer Read – Low Frequency (Opcode D1h)
SCK
CS
SI
SO
MSB MSB
2 3 1 0
1 1 0 1 0 0 1 0
6 7 5 4 10 11 9 8 12 63 66 67 65 64 62 33 34 31 32 29 30 68 71 72 70 69
Opcode
A A A A A A A A A
MSB
X X X X X X
MSB MSB
D D D D D D D D D D
Address Bits 32 Dummy Bits
Data Byte 1
High-impedance
SCK
CS
SI
SO
MSB MSB
2 310
1 1 0 1 0 1 0 0
6 754 10 1198 12 39 42 43414037 3833 36353431 3229 30 44 47 484645
Opcode
X X X X A A AX X
MSB
X X X X X X X X
MSB MSB
D D D D D D D DDD
Address Bits
Default Page Size = 16 Dummy Bits + BFA7-BFA0
Optional DataFlash-Lite Page Size =
15 Dummy Bits + BFA8-BFA0 Dummy Bits
Data Byte 1
High-impedance
SCK
CS
SI
SO
MSB MSB
2 310
1 1 0 1 0 0 0 1
6 754 10 1198 12 37 3833 36353431 3229 30 39 40
Opcode
X X X X A A AX X
MSB MSB
D D D D D D D D
DD
Data Byte 1
High-impedance
Address Bits
Default Page Size = 16 Dummy Bits + BFA7-BFA0
Optional DataFlash Page Size =
15 Dummy Bits + BA8-BFA0
54AT25PE20
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Figure 25-7. Read Sector Protection Register (Opcode 32h)
Figure 25-8. Read Security Register (Opcode 77h)
Figure 25-9. Status Register Read (Opcode D7h)
SCK
CS
SI
SO
MSB MSB
2 3 1 0
0 0 1 1 0 0 1 0
6 7 5 4 10 11 9 8 12 37 38 33 36 35 34 31 32 29 30 39 40
Opcode
X X X X X X X X X
MSB MSB
D D D D D D D
D D
Dummy Bits
Data Byte 1
High-impedance
SCK
CS
SI
SO
MSB MSB
2 3 1 0
0 1 1 1 0 1 1 1
6 7 5 4 10 11 9 8 12 37 38 33 36 35 34 31 32 29 30 39 40
Opcode
X X X X X X X X X
MSB MSB
D D D D D D D
D D
Dummy Bits
Data Byte 1
High-impedance
SCK
CS
SI
SO
MSB
2 3 1 0
1 1 0 1 0 1 1 1
6 7 5 4 10 11 9 8 12 21 22 17 20 19 18 15 16 13 14 23 24
Opcode
MSB MSB
D D D D D D D D D D
MSB
D D D D D D D D
Status Register Data Status Register Data
High-impedance
55AT25PE20
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Figure 25-10. Manufacturer and Device Read (Opcode 9Fh)
Figure 25-11.Reset Timing
Note: 1. The CS signal should be in the high state before the RESET signal is deasserted.
SCK
CS
SI
SO
60
9Fh
87 47
Opcode
1Fh 00h 01h 00h
Manufacturer ID Device ID
Byte 1
Device ID
Byte 2
EDI
String Length
EDI
Data Byte 1
High-impedance
14 1615 22 2423 38 403930 3231
Note: Each transition shown for SI and SO represents one byte (eight bits)
23h
CS
SCK
RESET
SO (Output) High-impedance High-impedance
SI (Input)
tRST
tREC tCSS
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26. Auto Page Rewrite Flowchart
Figure 26-1. Algorithm for Programming or Re-programming of the Entire Array Sequentially
Notes: 1. This type of algorithm is used for applications in which the entire array is programmed sequentially, filling the
array page-by-page.
2. A page can be written using either a Main Memory Page Program operation or a buffer write operation
followed by a buffer to Main Memory Page Program operation.
3. The algorithm above shows the programming of a single page. The algorithm will be repeated sequentially
for each page within the entire array.
START
Main Memory Page Program
through Buffer
(82h)
END
Provide Address
and Data
Buffer Write
(84h)
Buffer To Main
Memory Page Program
(83h)
57AT25PE20
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Figure 26-2. Algorithm for Programming or Re-programming of the Entire Array Randomly
Notes: 1. To preserve data integrity, each page of an DataFlash-L sector must be updated/rewritten at least once
within every 50,000 cumulative page erase and program operations.
2. A page address pointer must be maintained to indicate which page is to be rewritten. The auto page rewrite
command must use the address specified by the page address pointer
3. Other algorithms can be used to rewrite portions of the Flash array. Low-power applications may choose to
wait until 50,000 cumulative page erase and program operations have accumulated before rewriting all
pages of the sector.
START
Main Memory Page
to Buffer Transfer
(53h)
Increment Page
Address Pointer(2)
Auto Page Rewrite(2)
(58h)
END
Provide Address of
Page to Modify
If planning to modify multiple
bytes currently stored within
a page of the Flash array
Main Memory Page Program
through Buffer
(82h)
Buffer Write
(84h)
Buffer to Main
Memory Page Program
(83h)
58AT25PE20
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27. Ordering Information
27.1 Ordering Detail
27.2 Ordering Codes (Default 256 Byte DataFlash-L Page Size)
Notes: 1. The shipping carrier suffix is not marked on the device.
Device Grade
H = Green, NiPdAu lead finish,
Industrial temperature range
(–40°C to +85°C)
Designator
Product Family
Device Density
Shipping Carrier Option
Package Option
20 = 2-Mbit
25PE = DataFlash-L
B = Bulk (tubes)
T = Tape and reel
Y = Trays
Operating Voltage
N = 1.65V minimum (1.65V to 3.6V)
SS = 8-lead, 0.150” narrow SOIC
S = 8-lead, 0.208” wide SOIC
M = 8-pad, 5 x 6 x 0.6mm UDFN
A T 2 5 P E 2 0 - S S H N - B
Ordering Code Package Lead Finish Operating Voltage f
SCK
Device Grade
AT25PE20-SSHN-B
(1)
8S1
NiPdAu 1.65V to 3.6V 70MHz Industrial
(-40°C to 85°C)
AT25PE20-SSHN-T
(1)
AT25PE20-SHN-B
(1)
8S2
AT25PE20-SHN-T
(1)
AT25PE20-MHN-Y
(1)
8MA1
AT25PE20-MHN-T
(1)
Package Type
8S1 8-lead 0.150" wide, Plastic Gull Wing Small Outline (JEDEC SOIC)
8S2 8-lead 0.208" wide, Plastic Gull Wing Small Outline (EIAJ SOIC)
8MA1 8-pad (5 x 6 x 0.6mm body), Thermally Enhanced Plastic Ultra Thin Dual Flat No-lead (UDFN)
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28. Packaging Information
28.1 8S1 – 8-lead JEDEC SOIC
DRAWING NO. REV. TITLE GPC
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX NOTE
A1 0.10 – 0.25
A 1.35 – 1.75
b 0.31 – 0.51
C 0.17 – 0.25
D 4.80 – 5.05
E1 3.81 – 3.99
E 5.79 – 6.20
e 1.27 BSC
L 0.40 – 1.27
Ø 0° – 8°
Ø
E
1
N
TOP VIEW
C
E1
END VIEW
A
b
L
A1
e
D
SIDE VIEW
Package Drawing Contact:
contact@adestotech.com
8S1 G
6/22/11
Notes: This drawing is for general information only.
Refer to JEDEC Drawing MS-012, Variation AA
for proper dimensions, tolerances, datums, etc.
8S1, 8-lead (0.150” Wide Body), Plastic Gull Wing
Small Outline (JEDEC SOIC) SWB
60AT25PE20
DS-25PE20–139C–8/2018
28.2 8S2 – 8-lead EIAJ SOIC
TITLE DRAWING NO. GPC REV.
Package Drawing Contact:
contact@adestotech.com
8S2 STN F
8S2, 8-lead, 0.208” Body, Plastic Small
Outline Package (EIAJ)
4/15/08
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX NOTE
Notes: 1. This drawing is for general information only; refer to EIAJ Drawing EDR-7320 for additional information.
2. Mismatch of the upper and lower dies and resin burrs aren't included.
3. Determines the true geometric position.
4. Values b,C apply to plated terminal. The standard thickness of the plating layer shall measure between 0.007 to .021 mm.
A 1.70 2.16
A1 0.05 0.25
b 0.35 0.48 4
C 0.15 0.35 4
D 5.13 5.35
E1 5.18 5.40 2
E 7.70 8.26
L 0.51 0.85
q 0° 8°
e 1.27 BSC 3
q
1
N
E
TOP VIEW
C
E1
END VIEW
A
b
L
A1
e
D
SIDE VIEW
8.10
61AT25PE20
DS-25PE20–139C–8/2018
28.3 8MA1 – 8-pad UDFN
TITLE DRAWING NO.GPC REV.
Package Drawing Contact:
contact@adestotech.com 8MA1 YFG D
8MA1, 8-pad (5 x 6 x 0.6 mm Body), Thermally
Enhanced Plastic Ultra Thin Dual Flat No Lead
Package (UDFN)
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX N O T E
A 0.45 0.55 0.60
A1 0.00 0.02 0.05
b 0.35 0.40 0.48
C 0.152 REF
D 4.90 5.00 5.10
D2 3.80 4.00 4.20
E 5.90 6.00 6.10
E2 3.20 3.40 3.60
e 1.27
L 0.50 0.60 0.75
y 0.00 – 0.08
K 0.20 – –
4/15/08
Pin 1 ID
TOP VIEW
E
D
A1
A
SIDE VIEW
y
C
BOTTOM VIEW
E2
D2
L
b
e
1
2
3
4
8
7
6
5
Pin #1 Notch
(0.20 R)
0.45
K
Pin #1
Cham f e r
(C 0.35)
Option A
(Option B)
62AT25PE20
DS-25PE20–139C–8/2018
29. Revision History
Doc. Rev. Date Comments
DS-25PE20-139A 07/2017 Initial document release.
DS-25PE20-139B 03/2018 Change document status from ADVANCED to PRELIMINARY.
DS-25PE20-139C 08/2018
Change document status from PRELIMINARY to production.
Updated Figure 7-1.
Updated Figure 16-1.
Corporate Office
California | USA
Adesto Headquarters
3600 Peterson Way
Santa Clara, CA 95054
Phone: (+1) 408.400.0578
Email: contact@adestotech.com
© 2017 Adesto Technologies. All rights reserved. / Rev.: DS-25PE20–139C–8/2018
Disclaimer: Adesto Technologies Corporation makes no warranty for the use of its products, other than those expressly contained in the Company's standard warranty which is detailed in Adesto's Terms
and Conditions located on the Company's web site. The Company assumes no responsibility for any errors which may appear in this document, reserves the right to change devices or specifications
detailed herein at any time without notice, and does not make any commitment to update the information contained herein. No licenses to patents or other intellectual property of Adesto are granted by the
Company in connection with the sale of Adesto products, expressly or by implication. Adesto's products are not authorized for use as critical components in life support devices or systems.
Adesto®, the Adesto logo, CBRAM®, and DataFlash® are registered trademarks or trademarks of Adesto Technologies. All other marks are the property of their respective
owners. Adesto products in this datasheet are covered by certain Adesto patents registered in the United States and potentially other countries. Please refer to
http://www.adestotech.com/patents for details.
