6

X24C16

Flow 1. ACK Polling Sequence

Page Write

The X24C16 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 X24C16 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

seven bits of the 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 X24C16 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 X24C16 is still busy with the

write operation no ACK will be returned. If the X24C16

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.

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

3840 FHD F11

Figure 6. Page Write

BUS ACTIVITY:

MASTER

SDA LINE

BUS ACTIVITY:

X24C16

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

3840 FHD F12