24AA64/24LC64/24FC64
7.0
ACKNOWLEDGE POLLING
FIGURE 7-1:
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 and 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, then no ACK will be returned.
If no ACK is returned, the Start bit and control byte must
be re-sent. 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 7-1 for a
flow diagram of this operation.
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)?
Yes
Next
Operation
No
DS21189Q-page 10
©
2009 Microchip Technology Inc.
MICROCHIP [ MICROCHIP TECHNOLOGY ]
