DAC8734_091 Datasheet, PDF (24/41 Pages) Texas Instruments – Quad, 16-Bit, High-Accuracy, ±16V Output, Serial Input DIGITAL-TO-ANALOG CONVERTER

DAC8734
SBAS465A – MAY 2009 – REVISED SEPTEMBER 2009 .................................................................................................................................................. www.ti.com
Read-Back Operation
The READ command is used to start read-back operation. However, before read-back operation can be initiated,
the SDO pin must be enabled by clearing the DSDO bit in the Command Register (DSDO = '0'); this bit is cleared
by default. Read-back operation is then started by executing a READ command (R/W bit = '1'; see Table 2). Bits
A3 to A0 in the READ command select the register to be read. The remaining data in the command are don’t
care bits. During the next SPI operation, the data that appear on the SDO output are from the previously
addressed register. For a read of a single register, a NOP command can be used to clock out the data from the
selected register on SDO. Multiple registers can be read if multiple READ commands are issued. The readback
diagram in Figure 43 shows the read-back sequence. The read-back data format is the same format as what was
used to write to the device.
Single Reading
CS
SCLK
SDI
SDO
DB23
DB0
READ Command Specifies
Register to be Read
DB23
DB0
Undefined
Multiple Readings
CS
DB23
DB0
NOP Command
or Write Command
DB23
DB0
Data from
Selected Register
SCLK
SDI
SDO
DB23
DB0
Command to Read
Register A
DB23
DB0
Undefined
DB23
DB0
Command to Read
Register B
DB23
DB0
Data from
Register A
DB23
DB0
Command to Read
Register C
DB23
DB0
Data from
Register B
DB23
DB0
NOP Command
or Write Command
DB23
DB0
Data from
Register C
= Don’t Care
DB23 = MSB
DB0 = LSB
Figure 43. Read-Back Operation
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