24LC515 datasheet(10/24 Pages) MICROCHIP

10 / 24 page

24AA515/24LC515/24FC515

DS21673G-page 10

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

command has been issued from the master, the device

initiates the internally timed write cycle. ACK polling

can 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, then no ACK will be returned.

If no ACK is returned, then the Start bit and control byte

must be resent. 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

Note:

Care must be taken when polling the

24LC515. The control byte that was used

to initiate the write needs to match the

control byte used for polling.

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

24LC515 Datasheet(PDF) 10 Page - Microchip Technology