ACE24C02 Datasheet, PDF (9/20 Pages) ACE Technology Co., LTD. – Two-wire Serial EEPROM

ACE24C02/04/08/16B
Two-wire Serial EEPROM
The 16K does not use any device address bits but instead the 3 bits are used for memory page
addressing. These page addressing bits on the 4K, 8K and 16K devices should be considered the
most significant bits of the data word address which follows. The A0, A1 and A2 pins are no connect.
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 a write operation is initiated if this bit is low.
Upon a compare of the device address, the EEPROM will output a zero. If a compare is not made, the
chip will return to a standby state.
Write Operations
Byte Write:
A write operation requires an 8-bit data word address following the device address word and
acknowledgment. Upon receipt of this address, the EEPROM will again respond with a zero and then
clock in the first 8-bit data word. Following receipt of the 8-bit data word, the EEPROM will output a
zero 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, t_WR, to the nonvolatile
memory. All inputs are disabled during this write cycle and the EEPROM will not respond until the write
is complete (see to Figure 5).
Page Write:
The 2K EEPROM is capable of an 8-byte page write, and the 4K, 8K and 16K devices are capable of
16-byte page writes.
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 seven (2K) or fifteen (4K, 8K, 16K) 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 to Figure 6).
The data word address lower three (2K) or four (4K, 8K, 16K) 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 eight (2K) or sixteen (4K,
8K, 16K) data words are transmitted to the EEPROM, the data word address will “roll over” and previous
data will be overwritten.
Acknowledge Polling:
Once the internally timed write cycle has started and the EEPROM inputs are disabled, acknowledge
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.
Read Operations
Read operations are initiated the same way as write operations with the exception that the read/write
select bit in the device address word is set to one. There are three read operations: current address
read, random address read and sequential read.
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