X24C08

6

Page Write

The X24C08 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 fifteen more words. After the receipt of each

word, the X24C08 will respond with an acknowl-

edge.

After the receipt of each word, the four low order address bits

are internally incremented by one. The high order six

bits of the word address remain constant. If the master

should transmit more than sixteen words prior to gener-

ating 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

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 X24C08 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 X24C08 is still busy with the write

operation no ACK will be returned. If the X24C08

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

3842 FHD F11

Figure 6. Page Write

3842 FHD F12

BUS ACTIVITY:

MASTER

SDA LINE

BUS ACTIVITY:

X24C08

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

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