X24645
Flow 1. ACK Polling Sequence
Page Write
The X24645 is capable of a 32-byte page write operation.
It is initiated in the same manner as the byte write
WRITE OPERATION
COMPLETED
ENTER ACK POLLING
operation, but instead of terminating the write cycle after
the first data word is transferred, the master can
transmit up to thirty-one more bytes. After the receipt of
each byte, the X24645 will respond with an acknowledge.
ISSUE
START
After the receipt of each byte, the five low order
address bits are internally incremented by one. The high
order eight bits of the address remain constant. If the
master should transmit more than 32 bytes prior to gen-
ISSUE SLAVE
ADDRESS AND R/W = 0
ISSUE STOP
erating the stop condition, the address counter will “roll
over” and the previously written data will be overwritten
As with the byte write operation, all inputs are disabled
until completion of the internal write cycle. Refer to
ACK
RETURNED?
NO
Figure 6 for the address, acknowledge, and data
transfer sequence.
YES
Acknowledge Polling
The Max Write Cycle Time can be significantly reduced
using Acknowledge Polling. To initiate Acknowledge
NEXT
OPERATION
A WRITE?
NO
Polling, the master issues a start condition followed by the
Slave Address Byte for a write or read operation. If
YES
the device is still busy with the high voltage cycle, then no
ACK will be returned. If the device has completed
ISSUE BYTE
ADDRESS
ISSUE STOP
PROCEED
the write operation, an ACK will be returned and the
host can then proceed with the read or write operation.
Refer to Flow 1.
PROCEED
2783 ILL F09
Figure 6. Page Write
S
T
S
T
O
P
SLAVE
ADDRESS
A
R
T
BUS ACTIVITY:
MASTER
BYTE ADDRESS (n)
DATA n
DATA n+1
DATA n+31
SDA LINE
S
P
A
C
K
A
C
K
A
C
K
A
C
K
A
C
K
BUS ACTIVITY:
X24645
2783 ILL F10.2
6