DAC8574 Datasheet, PDF (34/40 Pages) Texas Instruments – QUAD, 16-BIT, LOW-POWER, VOLTAGE OUTPUT, I2C INTERFACE DIGITAL-TO-ANALOG CONVERTER

DAC8574
SLAS377A – JANUARY 2003 – REVISED JUNE 2003
www.ti.com
APPLICATION INFORMATION (continued)
DEV #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
A3 PIN
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Table 9. 64 Channel Address Decoding
C7 BIT
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
A2 PIN
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
C6 BIT
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
A1 PIN
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
A1 BIT
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
A0 PIN
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
A0 BIT
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Once a DAC8574 device is selected, channel select bits C2 and C1 can select a particular channel. Overall, I²C
address bits A1, A0, control bits C7, C6, C2 and C1 form the 6-bit address required to select one channel out of
64 possibilities.
Broadcast operation is supported for both I²C addressing and for extended addressing. A broadcast address
(10010000) makes all DAC8574 devices listen, regardless of the states of A0 and A1 pins. Also, a broadcast
command (C5 = C4 = 1) makes all devices listen, regardless of the states of A2 and A3 pins. The same
broadcast command (C5 = C4 = 1) also selects all channels for a given device, regardless of the states of
channel select bits. Thus, a global broadcast message that simultaneously updates up to 64 channels uses
10010000 as I²C address and has (C5 = C4 = 1) in the control word.
Examples
I²C Standard and Fast Mode Examples (A0, A1, A2, A3 and LDAC pins tied to GND):
EXAMPLE 1: WRITE 1/4 SCALE TO CHANNEL A
ADDRESS [7...0]
C [7...0]
M [7...0]
L [7...0]
START
1001 1000
ACK 0001 0000
ACK
0100 0000
ACK
0000 0000 ACK STOP
Previous VoutA output voltage is valid
VoutA = 1.25 V
EXAMPLE 2: WRITE 1/2 SCALE TO CHANNEL B
ADDRESS [7...0]
C [7...0]
M [7...0]
L [7...0]
START
1001 1000
ACK 0001 0010
ACK
0100 0000
ACK
0000 0000 ACK STOP
Previous VoutB output voltage is valid
VoutB = 2.50 V
EXAMPLE 3: WRITE 3/4 SCALE TO CHANNEL C
ADDRESS [7...0]
C [7...0]
M [7...0]
L [7...0]
START
1001 1000
ACK 0001 0100
ACK
1100 0000
ACK
0000 0000 ACK STOP
Previous VoutC output voltage is valid
VoutC = 3.75 V
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