DAC7678_14 Datasheet, PDF (30/53 Pages) Texas Instruments – 12-Bit, Octal-Channel, Ultra-Low Glitch, Voltage Output, Two-Wire Interface Digital-to-Analog Converter with 2.5V Internal Reference

DAC7678
SBAS493A – FEBRUARY 2010 – REVISED AUGUST 2010
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Broadcast Address Byte
Broadcast addressing, see Table 15, is also
supported by DAC7678. Broadcast addressing can
be used for synchronously updating or powering
down multiple DAC7678 devices. DAC7678 is
designed to work with other members of the
DACx578 family to support multichannel synchronous
update. Using the broadcast address, DAC7678
responds regardless of the states of the address pins.
Broadcast is supported only in write mode (Master
writes to DAC7678).
2. Then send a command byte for the register to be
read. The device will acknowledge this event
again.
3. Then send a repeated start with the slave
address and the R/W bit set to '1' for reading.
The device will also acknowledge this event.
4. Then the device writes the MSDB byte of the
addressed register. The master should
acknowledge this byte. Finally, the device writes
out the LSDB of the register as shown in
Table 16.
DAC7678 I²C READ SEQUENCE
To read any register other than the power-down
register the following command sequence should be
used:
An alternative reading method allows for reading back
the value of the last register written. The sequence is
a start/repeated start with slave address and the R/W
bit set to '1', and the two bytes of the last register are
read out.
1. Send a start or repeated start command with a
slave address and the R/W bit set to '0' for
writing. The device will acknowledge this event.
Note that it is not possible to use the broadcast
address for reading.
Table 14. LSDB
MSB
DB7
DB6
DB5
DB4
DB3
Least Significant Data Byte (LSDB)
DB2
DB1
LSB
DB0
MSB
1
0
Table 15. Broadcast Address Byte
0
0
1
1
LSB
1
0
Table 16. Read Sequence
S MSB … R/W(0) ACK MSB …
LSB ACK Sr MSB … R/W(1) ACK MSB … LSB ACK MSB …
LSB ACK
Address Byte
Command/Access Byte
Sr
Address Byte
MSDB
LSDB
From master
Slave
From master
Slave
From master
slave
From Slave
Master
From Slave
Master
30
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