PRELIMINARY TECHNICAL DATA

REV. PrF 09/2003

AD5380

–27–

Figure 13 . 2-Byte AD5380, I2C Write Operation

2-Byte Mode

Two byte mode allows the user update channels sequentially following initialization of this mode. The device address

byte is only required once and the pointer address pointer is configured for auto increment or burst mode.

The user must begin with an address byte (R/

W = 0) after which the DAC will acknowledge that it is prepared to

receive data by pulling SDA low. The address byte is followed by a specific pointer byte (FF Hex) which initiates

the burst mode of operation. The address pointer initializes to channel zero and the data following the pointer is

loaded to channel 0, the address pointer automatically increments to the next address.

The REG0 and REG 1 bits in the data byte determine the register to be updated. In this mode, following the initial-

ization only the 2-data bytes are required to update a channel, the channel address automatically increments from

address 0 to channel 39 and then returns to the normal 3-byte mode of operation. This mode allows transmission of

data to all channels in one block and reduces the software overhead in configuring all channels. A STOP condition at any

time exits this mode. Toggle mode of operation is not supported in 2-Byte Mode. Figure 13 shows a typical configura-

tion.

A7=1

MOST SIGNIFICANT DATA BYTE

LEAST SIGNIFICANT DATA BYTE

SCL

SDA

REG1

LSB

MSB

LSB

ACK

BY

AD538X

ACK

BY

AD538X

REG0

MSB

CHANNEL 0 DATA

1

0

10

1

AD0

R/

W

A0=1

ACK

BY

Converter

ACK

BY

Converter

MSB

ADDRESS BYTE

START

COND

BY

MASTER

SCL

SDA

POINTER BYTE

AD1

A5=1

A4=1

A3=1

A2=1

A1=1

MOST SIGNIFICANT DATA BYTE

LEAST SIGNIFICANT DATA BYTE

SCL

SDA

REG1

LSB

MSB

LSB

ACK

BY

Converter

ACK

BY

Converter

STOP

COND

BY

MASTER

REG0

MSB

MOST SIGNIFICANT DATA BYTE

LEAST SIGNIFICANT DATA BYTE

SCL

SDA

REG1

LSB

MSB

LSB

ACK

BY

Converter

ACK

BY

Converter

REG0

MSB

CHANNEL 1 DATA

CHANNEL N DATA FOLLOWED BY STOP

A6=1