X24042

6

Page Write

The X24042 is capable of a sixteen byte page write

operation. It is initiated in the same manner as the byte

write operation, but instead of terminating the write cycle

after the first data word is transferred, the master can

transmit up to seven more words. After the receipt of

each word, the X24042 will respond with an acknowl-

edge.

After the receipt of each word, the three low order

address bits are internally incremented by one. The high

order eight bits of the word address remain constant.

The master should not transmit more than eight words

prior to generating the stop condition. As with the byte

write operation, all inputs are disabled until completion

of the internal write cycle. Refer to Figure 6 for the

address, acknowledge and data transfer sequence.

Acknowledge Polling

The disabling of the inputs can be used to take advan-

tage of the typical 5 ms write cycle time. Once the stop

condition is issued to indicate the end of the host’s write

operation the X24042 initiates the internal write cycle.

ACK polling can be initiated immediately. This involves

issuing the start condition followed by the slave address

for a write operation. If the X24042 is still busy with the

write operation no ACK will be returned. If the X24042

has completed the write operation an ACK will be

returned and the host can then proceed with the next

read or write operation. Refer to Flow 1.

Flow 1. ACK Polling Sequence

3849 FHD F11

Figure 6. Page Write

3849 FHD F12

WRITE OPERATION

COMPLETED

ENTER ACK POLLING

ISSUE

START

ISSUE SLAVE

ADDRESS AND R/W = 0

ACK

RETURNED?

NEXT

OPERATION

A WRITE?

ISSUE BYTE

ADDRESS

PROCEED

ISSUE STOP

NO

YES

YES

PROCEED

ISSUE STOP

NO

BUS ACTIVITY:

MASTER

SDA LINE

BUS ACTIVITY:

X24042

S

T

A

R

T

SLAVE

ADDRESS

S

S

T

O

P

P

A

C

K

A

C

K

A

C

K

A

C

K

A

C

K

WORD ADDRESS n

DATA n

DATA n+1

DATA n+15

NOTE: In this example n = xxxx 000 (B); x = 1 or 0