ACE24LA02.04.08.16A

Two-wire Serial EEPROM

VER 1.1

6

Figure 3: Output Acknowledge

Device Addressing

The 2K/4K/8K/16K EEPROM devices all require an 8-bit device address word following a start condition

to enable the chip for a read or write operation (see Figure 4)

The device address word consists of a mandatory "1", "0" sequence for the first four most significant bits

as shown. This is common to all the Serial EEPROM devices.

The next 3 bits are the A2, A1 and A0 device address bits for the 2K EEPROM. These 3 bits must

compare to their corresponding hardwired input pins.

The 4K EEPROM only uses the A2 and A1 device address bits with the third bit being a memory page

address bit. The two device address bits must compare to their corresponding hardwired input pins. The

A0 pin is no connecting.

The 8K EEPROM only uses the A2 device address bit with the next 2 bits being for memory page

addressing. The A2 bit must compare to its corresponding hard-wired input pin. The A1 and A0 pins are

no connecting.

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 "0". 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 "0" and then clock

in the first 8-bit data word. Following receipt of the 8-bit data word, the EEPROM will output a "0" and the