33702 datasheet(21/24 Pages) MOTOROLA

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MOTOROLA ANALOG INTEGRATED CIRCUIT DEVICE DATA

33702

Communication Stop

Only the master can terminate the data transfer by issuing a

STOP condition. The slave waits for this condition to resume its

initial state waiting for the next START condition (see

Figure 19).

Data Transfer Example

The master device controlling the I2C bus will always start

addressing a 33702 slave IC in writing mode (R/W = 0) in order

to be able to write a Command Byte just after the address

acknowledge. I2C bus protocol defines this circumstance as a

master-transmitter and slave-receiver configuration.

Eventually this Command Byte can again define a Write

operation (e.g., Voltage Margining, see Figure 19), and the

master will keep the data transfer direction.

Figure 19 illustrates a communication beginning with the

slave address, the first command for voltage margining, and a

third byte containing the address field 001 and the value field

00101 corresponding with the LDO fifth setting (LDO output

voltage = +5% above its nominal value). If a simultaneous

setting for switcher is needed, a fourth byte should be included

before the STOP condition (P); for instance, 001 10010 to set

switcher in its second setting (switcher output voltage = +2%

above its nominal value).

Figure 19. Complete Data Transfer Example

START

Slave Address

Write

First Command for Voltage Margining

Address Field Value Field = LDO

5th Setting

STOP

Ack

0Ack

Ack

1 00

A3 A2 A1

Freescale Semiconductor, Inc.

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Go to: www.freescale.com

33702 датащи(PDF) 21 Page - Motorola, Inc