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SLAVE ADDRESS R/W

A

Ctrl/MS-Byte

A

LS-Byte

A/A

P

”0” (write)

Data Transferred

(n* Words + Acknowledge)

Word = 16 Bit

From Master to DAC7571

From DAC7571 to Master

A = Acknowledge (SDA LOW)

A = Not Acknowledge (SDA HIGH)

S = START Condition

Sr = Repeated START Condition

P = STOP Condition

1

0

0

1

1

0

A0

R/W

MSB

LSB

Factory Preset

Standard-and Fast-Mode:

S

HS-Master Code

R/W

A

Ctrl/MS-Byte

A

LS-Byte

A/A

P

”0” (write)

Data Transferred

(n* Words + Acknowledge)

Word = 16 Bit

High-Speed-Mode (HS-Mode):

S

A Sr Slave Address

HS-Mode Continues

F/S-Mode

HS-Mode

F/S-Mode

Sr Slave Address

0

0

0

0

1

X

X

R/W

MSB

LSB

HS-Mode Master Code:

0

0

PD1

PD2

D11

D10

D9

D8

MSB

LSB

Ctrl/MS-Byte:

D7

D6

D5

D4

D3

D2

D1

D0

MSB

LSB

LS-Byte:

D11 – D0 = Data Bits

‘0’ = Write to DAC7571

‘1’ = Read from DAC7571

ADDRESS BYTE

DAC7571

SLAS374A – FEBRUARY 2003 – REVISED JANUARY 2004

THEORY OF OPERATION (continued)

Figure 45. Master Transmitter Addressing DAC7571 as a Slave Receiver With a 7-Bit Address

MSB

R/W

1

0

0

1

1

0

A0

0

The address byte is the first byte received by the DAC7571 following the START condition from the master

device. The first five bits (MSBs) of the slave address are factory preset to 100110. The next bit of the address

byte is the device select bit, A0. In order for DAC7571 to respond, the logic state of address bit A0 should match

the logic state of address pin A0. A maximum of two devices with the same preset code can therefore be

be actively driven by TTL or CMOS logic levels. The device address is set by the state of the A0 pin upon

power-up of the DAC7571. The last bit of the address byte (R/W) should always be zero. Following the START

condition, the DAC7571 monitors the SDA bus, checking the device type identifier being transmitted. Upon

receiving the 100110 code, the appropriate device select bit and the R/W bit, the DAC7571 outputs an

acknowledge signal on the SDA line. Upon receipt of a broadcast address 10010000, the DAC7571 responds

regardless of the state of the A0 pin.

16