Instruction Manual

W90P710CD/W90P710CDG

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6.18.1 I

C Protocol

Normally, a standard communication consists of four parts:

1) START or Repeated START signal generation

2) Slave address transfer

3) Data transfer

4) STOP signal generation

SCL

SDA

MSB

ACK

LSB MSB LSB

1 2 7 8 9 1 2 3 - 7 8 9

A6 A5 A4 - A1 A0 R/W D7 D6 D5 - D1 D0

NACK

ACK

Fig. 6.18.1.1 Data transfer on the I

C-bus

S SLAVE ADDRESS R/W A DATA A DATA A/A P

'0'(write)

data transfer

(n bytes + acknowledge)

from master to slave

from slave to master

A = acknowledge (SDA low)

A = not acknowledge (SDA high)

S = START condition

P = STOP condition

A master-transmitter addressing a slave receiver with a 7-bit address

The transfer direction is not changed

'1'(read)

data transfer

(n bytes + acknowledge)

S SLAVE ADDRESS R/W A DATA A DATA A P

A master reads a slave immediately after the first byte (address)