1997 Feb 13

10

Philips Semiconductors

Product specification

256 to 1024

× 8-bit CMOS EEPROMs with

PCF85xxC-2 family

8.5

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 sequential read.

8.5.1

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.8 Master reads PCF85xxC-2 slave after setting word address (write word address; read data).

handbook, full pagewidth

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 - 1

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.9 Master reads PCF85xxC-2 immediately after first byte (read mode).

handbook, full pagewidth

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