10
Atmel AT30TSE002B [DATASHEET]
8711G–SEEPR–5/12
7. Device Addressing
AT30TSE002B device requires an 8-bit device address word following a start condition to enable the chip to access
either the Temperature Sensor or EEPROM functions (See Table 7-1).
Table 7-1. Control/Device Address Word
Note: 1. X = User Selectable
The EEPROM device address word consists of a mandatory one-zero sequence for the first four most significant bits
(‘1010’) for normal read and write operations, a ‘0110’ for writing to the EEPROM write protect register and ‘0011’ for
Temperature Sensor operations. The next three bits are the A2, A1 and A0 device address bits for the AT30TSE002B
device. These three bits must match their corresponding hard-wired input pins. The eighth bit of the device address is the
read/write operation select bit. A read operation is initiated if this bit is high and an EEPROM write operation is selected if
this bit is low. Upon a compare of the device address, the device will output a zero, called an Acknowledge (ACK). If a
compare is not made, the chip will not ACK and will return to a standby state. The EEPROM will not ACK if the write
protect register has been programmed and the control code is ‘0110’.
8. EEPROM Write Operations
Byte Write: A write operation requires an 8-bit data word address following the device address word and ACK. Upon
receipt of this address, the EEPROM will again respond with an ACK and then clock in the first 8-bit data word. Following
receipt of the 8-bit data word, the EEPROM will output an ACK and the addressing device, such as a microcontroller,
must terminate the write sequence with a stop condition. At this time the EEPROM enters an internally timed write cycle,
tWR, to the nonvolatile memory. All inputs are disabled during this write cycle and the EEPROM will not respond until the
write is complete (see Figure 13-2 and Figure 13-3).
The device will acknowledge a write command, but not write the data, if the software write protection has been enabled.
The write cycle time must be observed even when the write protection is enabled.
Page Write: The 2K EEPROM device is capable of 16-byte page write. A page write is initiated the same as a byte write,
but the microcontroller does not send a stop condition after the first data word is clocked in. Instead, after the EEPROM
acknowledges receipt of the first data word, the microcontroller can transmit up to fifteen more data words. The EEPROM
will respond with a zero after each data word received. The microcontroller must terminate the page write sequence with
a stop condition (see Figure 13-3). The data word address lower four bits are internally incremented following the receipt
of each data word. The higher data word address bits are not incremented, retaining the memory page row location.
When the word address, internally generated, reaches the page boundary, the following byte is placed at the beginning
of the same page. If more than sixteen data words are transmitted to the EEPROM, the data word address will “roll over”
and previous data will be overwritten. The address “roll over” during write is from the last byte of the current page to the
first byte of the same page. The device will acknowledge a write command, but not write the data, if the software write
protection has been enabled. The write cycle time must be observed even when the write protection is enabled.
Acknowledge (ACK) Polling: Once the internally-timed write cycle has started and the EEPROM inputs are disabled,
ACK polling can be initiated. This involves sending a start condition followed by the device address word. The read/write
bit is representative of the operation desired. Only if the internal write cycle has completed will the EEPROM respond
with a zero allowing the read or write sequence to continue.
Device
Control / Device Address Word
Device ID Device Address Bits R/W
B7 B6 B5 B4 A2 A1 A0 B0
EEPROM 1 0 1 0
X X X XTemperature Sensor 0 0 1 1
EEPROM Write Protection 0 1 1 0