24LC64XT-ESLASHMS datasheet(9/24 Pages) MICROCHIP

9 / 24 page

 2002 Microchip Technology Inc.

DS21189F-page 9

24AA64/24LC64

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 com-

mand has been issued from the master, the device ini-

tiates the internally timed write cycle. ACK polling can

be initiated immediately. This involves the master send-

ing 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, then no ACK will be returned. If no

ACK is returned, then the START bit and control byte

must be re-sent. If the cycle is complete, then the

device will return the ACK and the master can then pro-

ceed with the next read or write command. See

Figure 5-1 for flow diagram.

FIGURE 5-1:

ACKNOWLEDGE POLLING

FLOW

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

24LC64XT-E/MS Datasheet(PDF) 9 Page - Microchip Technology