ACE24LA128A

Two-wire Serial EEPROM

VER 1.1

7

Page Write:

The 128K EEPROM is capable of a 64-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 63 more

data words. The EEPROM will respond with a “0” after each data word received. The microcontroller must

terminate the page write sequence with a stop condition (see Figure 6).

The data word addresses lower five 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 64 data words are transmitted to the EEPROM, the data word

Write Identification Page:

The Identification Page (64 bytes) is an additional page which can be written and (later) permanently

locked in Read-only mode. It is written by issuing the Write Identification Page instruction. This instruction

uses the same protocol and format as Page Write (into memory array), except for the following

differences:

⚫

Device type identifier = 1011b

⚫

MSB address bits B15/B6 are don't care except for address bit B10 which must be "0". LSB address

bits B5/B0 define the byte address inside the Identification page.

If the Identification page is locked, the data bytes transferred during the Write Identification Page

instruction are not acknowledged (NoAck).

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 "0", allowing the read or write sequence to continue.