PCA9558_4

© NXP B.V. 2009. All rights reserved.

Product data sheet

Rev. 04 — 14 April 2009

13 of 27

NXP Semiconductors

PCA9558

7.1.3.5

256-byte EEPROM write to GPIO

A mode is available whereby a byte of data in the 256-byte EEPROM array can be written

indicating a read from the 256-byte EEPROM and write to the GPIO is sent, followed by

the word address of the data within the EEPROM array. Upon Acknowledge from the

slave, the data is sent to the GPIO. See Figure 16.

7.1.3.6

256-byte EEPROM write from GPIO

A mode is available whereby data in the GPIO (IP register) can be written to the 256-byte

from the GPIO and write to the 256-byte EEPROM is sent, followed by the word address

for the data to be written. Once the slave has sent an Acknowledge, the master must send

a STOP condition. See Figure 17.

After the STOP condition, the E/W cycle starts, and the parts will not respond to any

request to access the EEPROM array until the cycle finishes, approximately 4 ms.

M bytes where M

≥ 1.

00111

A0

0

A

S1

START condition

R/W

002aad379

A

acknowledge

from slave

P

slave address

STOP

condition

command code

000001

01

(cont.)

(cont.)

EEPROM address

A

acknowledge

from slave

DATA N

DATA N + M

A

acknowledge

from master

Auto-Increment

word address

NA

no acknowledge

from master

Auto-Increment

word address

00111

A0

1

1

R/W

slave address

A

acknowledge

from slave

S

(re)START condition

acknowledge

from slave

See Table 3 for the needed command code.

Fig 16. Read from 256-byte EEPROM and write to GPIO registers

00111

A0

0

A

S1

START condition

R/W

acknowledge

from slave

002aad380

A

acknowledge

from slave

P

slave address

STOP condition;

data latched into

GPIO register

NA

no acknowledge

from master

data from 256-byte EEPROM

command byte

0

0

xxxx

0x

d6 d5 d4 d3 d2 d1 d0

00111

A0

1

A

S1

(re)START

condition

R/W

acknowledge

from slave

slave address

(cont.)

(cont.)

d7

EEPROM address

a6 a5 a4 a3 a2 a1 a0

a7

A

acknowledge

from slave