Datasheet

24AA01/24LC01B

DS21711C-page 8  2003 Microchip Technology Inc.

5.0 ACKNOWLEDGE POLLING

Since the device will not acknowledge during a write

cycle, this can be used to determine when the cycle is

complete (this feature can be used to maximize bus

throughput). Once the Stop condition for a Write

command has been issued from the master, the device

initiates the internally-timed write cycle. ACK polling

can then be initiated immediately. This involves the

master sending a Start condition followed by the control

byte for a Write command (R/W

= 0). If the device is still

busy with the write cycle, no ACK will be returned. If the

cycle is complete, the device will return the ACK and

the master can then proceed with the next Read or

Write command. See Figure 5-1 for a flow diagram of

this operation.

FIGURE 5-1: ACKNOWLEDGE POLLING

FLOW

6.0 WRITE-PROTECTION

The 24XX01 can be used as a serial ROM when the

WP pin is connected to V

CC. Programming will be

inhibited and the entire memory will be write-protected.

Send

Write Command

Send Stop

Condition to

Initiate Write Cycle

Send Start

Send Control Byte

with R/W

= 0

Did Device

Acknowledge

(ACK = 0)?

Operation

Yes