1997 Apr 02

7

Philips Semiconductors

Product specification

128

PCA8581; PCA8581C

7.5

PCA8581 WRITE and READ cycles is shown in Figs 7, 9 and 10.

After the word address, one-to-eight data bytes can be sent. The address is automatically incremented, but the four

highest address bits (row) are internally latched. Therefore all bytes are written in the same row.

An example of writing eight bytes with word address X 0 0 00000 and six bytes with word address X 0010101 is

shown in Fig.8.

Fig.7 Master transmits to slave receiver (WRITE) mode.

handbook, full pagewidth

S

0A X

SLAVE ADDRESS

WORD ADDRESS

A

A

DATA

P

acknowledgement

from slave

acknowledgement

from slave

acknowledgement

from slave

WRITING

R/W don't

care

auto increment

memory word address

MLB889

n bytes

t WR

Fig.8 Writing eight and six bytes with different word addresses.

(1) X = don’t care.

handbook, full pagewidth

MLB890

Word Address

(1)

Row

0

1

2

3

column

1

4

2

5

3

6

4

5

6

1

7

2

8

3

01

23

45

67

X0000000

X0001...

X0010101

X0011...