Datasheet

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Examples
I
2
C Standard and Fast Mode Examples (A0, A1, A2, A3 and LDAC pins tied to GND):
DAC8574
SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004
Table 9. 64 Channel Address Decoding
DEV # A3 PIN C7 BIT A2 PIN C6 BIT A1 PIN A1 BIT A0 PIN A0 BIT
1 0 0 0 0 0 0 0 0
2 0 0 0 0 0 0 1 1
3 0 0 0 0 1 1 0 0
4 0 0 0 0 1 1 1 1
5 0 0 1 1 0 0 0 0
6 0 0 1 1 0 0 1 1
7 0 0 1 1 1 1 0 0
8 0 0 1 1 1 1 1 1
9 1 1 0 0 0 0 0 0
10 1 1 0 0 0 0 1 1
11 1 1 0 0 1 1 0 0
12 1 1 0 0 1 1 1 1
13 1 1 1 1 0 0 0 0
14 1 1 1 1 0 0 1 1
15 1 1 1 1 1 1 0 0
16 1 1 1 1 1 1 1 1
Once a DAC8574 device is selected, channel select bits C2 and C1 can select a particular channel. Overall, I
2
C
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 I
2
C 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 I
2
C address and has (C5 = C4 = 1) in the control word.
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 1000 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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