24LC024/24LC025

DS21210A-page 8

Preliminary

© 1997 Microchip Technology Inc.

7.0

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 proceed with

the next read or write command. See Figure 7-1 for flow

diagram.

FIGURE 7-1:

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)?

Next

Operation

NO

YES