BYTE-WIDE SmartVoltage FlashFile™ MEMORY FAMILY E
18 PRELIMINARY
When the block erase is complete, status register
bit SR. 5 should be checked. I f a block erase error i s
detected, the status register should be cleared
before system software attempts corrective actions.
The CUI remains in read status register mode until
a new command is issued.
This two-step command sequence of set-up
followed by execution ensures that block contents
are not accidentally erased. An invalid Block Erase
command sequence will result in both status
register bits SR.4 and SR.5 being set to “1.” Also,
reliable block erasure can only occur when
VCC = VCC2/3 and VPP = VPPH1/2/3. In the abs ence of
this high voltage, block contents are protected
against erasure. If block erase is attempted while
VPP ≤ V
PPLK, SR.3 and SR.5 will be set to “1.”
Successful block erase requires that the
corresponding block lock-bit be cleared or, if set,
that RP# = VHH. If block erase is attempted when
the corresponding block lock-bit is set and
RP# = VIH, the block erase will fail, and SR.1 and
SR.5 will be set to “1.” Block erase operations with
VIH < RP# < VHH produce spurious results and
should not be attempted.
4.6 Program Command
Program is executed by a two-cycle command
sequence. Program setup (standard 40H or
alternate 10H) i s writ ten, fol lowed by a s econd writ e
that specifies the address and data (latched on the
rising edge of WE#). The WSM then takes over,
controlling the program and write verify algorithms
internally. After the program sequence is written,
the device automatically outputs status register
data when read (see Figure 8). The CP U can det ect
the completion of the program event by analyzing
the RY/BY# pin or status register bit SR.7.
When program is complete, s tatus register bit SR.4
should be check ed. I f program error i s det ect ed, t he
status register should be c l eared. The internal WSM
verify only detects errors for “1”s that do not
successfully write to “0”s. The CUI remains in read
status register mode until it receives another
command.
Reliable programs only occurs when VCC = VCC2/3
and VPP = VPPH1/2/3. In the absence of this high
voltage, memory contents are protected against
programs. If program is attempted while
VPP ≤ V
PPLK, the operation will fail, and status
register bits SR.3 and SR.5 will be set to “1.”
Successful program also requires that the
corresponding block lock-bit be cleared or, if set,
that RP# = VHH. If program is attempted when the
corresponding block lock-bit is set and RP# = VIH,
program will fail, and SR.1 and SR.4 will be set to
“1.” Program operations with VIH < RP# < VHH
produce spurious results and should not be
attempted.
4.7 Block Erase Suspend
Command
The Block Erase Suspend command allows
block-erase interruption to read or write data in
another block of memory. Once the block erase
process starts, writing the Block Erase Suspend
command requests that the WSM suspend the
block erase sequence at a predetermined point in
the algorithm. The device outputs status register
data when read after the Block Erase Suspend
command is written. Polling status register bits
SR.7 and SR. 6 can determine when the block erase
operation has been suspended (both will be set to
“1”). RY/BY# will also transition to VOH.
Specification tWHRH2 defines the block erase
suspend latency.
At thi s point , a Read A rray c omm and can be writ ten
to read data from blocks other than that which is
suspended. A Program command sequence can
also be issued during erase suspend to program
data in other blocks. Using the Program Suspend
command (see Section 4.8), a program operation
can also be suspended. During a program operation
with block erase suspended, status register bit
SR.7 will return to “0” and the RY/BY# output will
transition to VOL. However, SR.6 will remain “1” to
indicate block erase suspend status.
The only other v alid c omm ands whil e block erase is
suspended are Read Status Register and Block
Erase Resume. After a Block Erase Resume
command is written to the flash memory, the WSM
will continue the block erase process. Status
register bits SR.6 and SR.7 will automatically clear
and RY/BY# will return to VOL. After the Erase
Resume command is written, the device
automatically outputs status register data when
read (see Figure 9). VPP must remain at VPPH1/2/3
(the same VPP level used for block erase) while
block erase is sus pended. RP# mus t also rem ain at
VIH or VHH (the same RP# level used for block
erase). Block erase cannot resume until program
operations initiated during block erase suspend
have completed.