1997 Oct 21

17

Philips Semiconductors

Product specification

PCF8584

Fig.7 PCF8584 master receiver mode.

(1) The first read of the S0 register is a ‘dummy read’ of the slave address which should be discarded. The first read of the S0 register simultaneously

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A0 = LOW

Load 'Slave Address' into S0 register:

'Slave Address' = 7 bits

+ R/W = 1.

PCF8584 generates 'START' condition,

sends out slave address

generates 9th clock pulse for slave ACK.

Set-up software counters.

Set ACK bit S1 to 0 in

preparation for negative

acknowledgement.

PCF8584 generates

'STOP' condition.

PCF8584 goes into

slave receiver mode.

This command transfers

the final data byte from

the data buffer to accumulator.

Because the STOP condition

was previously executed, no

This command simultaneously

receives the final data byte

it into register S0.

Neg. ACK is also sent.

is bus busy?

(BB = 0?)

START

END

send byte 'slave address' to S0

A0 = HIGH

read byte from S1 status register

A0 = HIGH

send byte C5H to S1 control register

A0 = HIGH

read byte from S1 status register

A0 = LOW

n = n

+ 1

n = 0 (data byte counter)

m = number of data bytes

to be read

yes

no

A0 = HIGH

send byte 40H to control register S1

A0 = LOW

A0 = HIGH

read byte from S1 status register

A0 = HIGH

send byte C3H to S1

A0 = LOW

read final data byte from S0 register

PIN = 0?

no

yes

slave ACK?

(LRB = 0?)

n = m

− 1?

yes

no

no

(an error

has occured)

PIN = 0?

yes

MGL009