EVAL-AD7327CB AD [Analog Devices], EVAL-AD7327CB Datasheet - Page 26

• Manufacturer Part Number: EVAL-AD7327CB
• Description: 500 kSPS, 8-Channel, Software-Selectable, True Bipolar Input, 12-Bit Plus Sign ADC
• Manufacturer: AD [Analog Devices]

AD7327
SEQUENCER OPERATION
The AD7327 can be configured to automatically cycle through a
number of selected channels using the on-chip sequence register
with the Seq1 bit and the Seq2 bit in the control register. Figure 44
shows how to program the AD7327 register to operate in
sequence mode.
After power-up, all of the four on-chip registers contain default
values. Each analog input has a default input range of ±10 V. If
different analog input ranges are required, a write to the range
registers is required. This is shown in the first two serial
transfers of Figure 44.
CS
FROM CHANNEL IN SEQUENCE.
SEQUENCE, Seq1 = 0, Seq2 = 0.
DOUT: CONVERSION RESULT
DIN: WRITE TO CONTROL
REGISTER TO STOP THE
CS
CS
CS
CS
CS
CS
Figure 44. Programmable Sequence Flowchart
A SEQUENCE.
DIN: TIE DIN LOW/WRITE BIT = 0 TO CONTINUE TO CONVERT
DIN: WRITE TO RANGE REGISTER 1 TO SELECT THE RANGE
DIN: WRITE TO RANGE REGISTER 2 TO SELECT THE RANGE
STOPPING
DOUT: CONVERSION RESULT FROM FIRST CHANNEL IN
DOUT: CONVERSION RESULT FROM CHANNEL 0, ±10V
DIN: WRITE TO SEQUENCE REGISTER TO SELECT THE
DIN: WRITE TO SEQUENCE REGISTER TO SELECT THE
DIN: WRITE TO CONTROL REGISTER TO START THE
DOUT: CONVERSION RESULT FROM CHANNEL X IN
DOUT: CONVERSION RESULT FROM CHANNEL 0,
DOUT: CONVERSION RESULT FROM CHANNEL 0,
DOUT: CONVERSION RESULT FROM CHANNEL 0,
ANALOG INPUT CHANNELS TO BE INCLUDED IN
SINGLE-ENDED MODE, RANGE SELECTED IN
SINGLE-ENDED MODE, RANGE SELECTED IN
SINGLE-ENDED MODE, RANGE SELECTED IN
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THROUGH THE SEQUENCE OF CHANNELS.
SELECTING A NEW SEQUENCE.
FOR EACH ANALOG INPUT CHANNEL.
FOR EACH ANALOG INPUT CHANNEL.
RANGE, SINGLE-ENDED MODE.
SEQUENCE, Seq1 = 0, Seq2 = 1.
THE FIRST SEQUENCE.
RANGE REGISTER 1.
RANGE REGISTER 1.
RANGE REGISTER 1.
NEW SEQUENCE.
THE SEQUENCE.
THE SEQUENCE.
POWER ON.
These two initial serial transfers are only necessary if input
ranges other than the default ranges are required. After the
analog input ranges are configured, a write to the sequence
register is necessary to select the channels to be included in the
sequence. Once the channels for the sequence have been
selected, the sequence can be initiated by writing to the control
register and setting Seq1 to 0 and Seq2 to 1. The AD7327
continues to convert through the selected sequence without
interruption provided the sequence register remains unchanged
and Seq1 = 0 and Seq2 = 1 in the control register.
ON THE SELECTED SEQUENCE
CONTINUOUSLY CONVERT
OF CHANNELS.
DIN TIED LOW/WRITE BIT = 0.