X24325
Page Write
Flow 1. ACK Polling Sequence
The X24325 is capable of a 32 byte page write opera-
tion. It is initiated in the same manner as the byte write
operation, but instead of terminating the write cycle af-
ter the first data word is transferred, the master can
transmit up to fifteen more words. After the receipt of
each word, the X24325 will respond with an acknowl-
edge.
WRITE OPERATION
COMPLETED
ENTER ACK POLLING
ISSUE
START
After the receipt of each word, the five low order ad-
dress bits are internally incremented by one. The high
order bits of the word address remain constant. If the
master should transmit more than 32 words prior to
generating the stop condition, the address counter will
“roll over” and the previously written data will be over-
written. As with the byte write operation, all inputs are
disabled until completion of the internal write cycle. Re-
fer to Figure 6 for the address, acknowledge and data
transfer sequence.
ISSUE SLAVE
ADDRESS AND R/W = 0
ISSUE STOP
ACK
NO
RETURNED?
YES
Acknowledge Polling
The Max Write Cycle Time can be significantly reduced
using Acknowledge Polling. To initiate Acknowledge
Polling, the master issues a start condition followed by
the Slave Address Byte for a write or read operation. If
the device is still busy with the high voltage cycle, then
no ACK will be returned. If the device has completed
the write operation, an ACK will be returned and the
host can then proceed with the read or write operation.
Refer to Flow 1.
NEXT
NO
OPERATION
A WRITE?
YES
ISSUE BYTE
ADDRESS
ISSUE STOP
PROCEED
PROCEED
6552 ILL F09
Figure 6. Page Write
S
T
S
T
O
P
SLAVE
ADDRESS
A
R
T
BUS ACTIVITY:
MASTER
WORD 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:
X24325
6552 ILL F10.1
6
XICOR [ XICOR INC. ]
