Philips Semiconductors

PCF85103C-2

256

Product data

Rev. 02 — 09 May 2002

9 of 20

9397 750 09646

© Koninklijke Philips Electronics N.V. 2002. All rights reserved.

8.1.5

Read operations

Read operations are initiated in the same manner as write operations with the

exception that the LSB of the slave address is set to logic 1.

There are three basic read operations: current address read, random read, and

sequential read.

Remark: The lower 8 bits of the word address are incremented after each

transmission of a data byte (read or write). The MSB of the word address, which is

defined in the slave address, is not changed when the word address count overflows.

Thus, the word address overflows from 255 to 0, and from 511 to 256.

Fig 7.

Master reads PCF85103C-2 slave after setting word address (write word address; read data);

sequential read.

S0 A

SLAVE ADDRESS

WORD ADDRESS

A

A

SLAVE ADDRESS

acknowledge

from slave

acknowledge

from slave

acknowledge

from slave

R/W

acknowledge

from master

A

DATA

auto increment

word address

MBA703

P

no acknowledge

from master

1

DATA

auto increment

word address

last byte

R/W

S1

n bytes

at this moment master

transmitter becomes

master receiver and

EEPROM slave receiver

becomes slave transmitter

Fig 8.

Master reads PCF85103C-2 immediately after first byte (read mode); current address read.

S

1A

SLAVE ADDRESS

DATA

A1

DATA

acknowledge

from slave

acknowledge

from master

no acknowledge

from master

R/W

auto increment

word address

MBA704 - 1

auto increment

word address

n bytes

last bytes

P