24AA64/24LC64
FIGURE 7-1: ACKNOWLEDGE POLLING
FLOW
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.
Send
Write Command
Send Stop
Condition to
Initiate Write Cycle
Send Start
Send Control Byte
with R/W = 0
Did Device
NO
Acknowledge
(ACK = 0)?
YES
Next
Operation
DS21189B-page 8
1998 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
