ACE24AC512E

Two-wire Serial EEPROM

VER 1.1

6

Write Operations

(A)

Byte Write

A write operation requires two 8-bit data word address following the device address word and

acknowledge

signal. Upon receipt of this address, the EEPROM will respond with a “0” and then

clock in the first 8-bit data word.

Following receipt of the 8-bit data word, the EEPROM will again

output a “0”. The addressing device, such as a microcontroller, must terminate the write sequence

with a stop condition. At this time the EEPROM enters into an internally-timed write cycle state. All

inputs are disabled during this write cycle and the EEPROM will not respond until the writing is

completed (figure 3).

(B)

Page Write

The 512K EEPROM are capable of 128-byte page write.

A page write is initiated the same way as a byte write, but the microcontroller does not send a stop

condition after the first data word is clocked in. The microcontroller can transmit up to 127 more data

words after the EEPROM acknowledges receipt of the first data word. The EEPROM will respond

with a “0” after each data word is received. The microcontroller must terminate the page write

sequence with a stop condition (see Figure 4).

The lower five bits of the data word address 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.

If more than 64 data words are transmitted to the EEPROM, the data word address will

“roll over” and the previous data will be overwritten.

(C)

Acknowledge Polling

Acknowledge polling may be used to poll the programming status during a self-timed internal

programming. By issuing a valid read or write address command, the EEPROM will not acknowledge

programming completes and the chip has returned to the standby mode, the device will return a valid