EVAL-AD7327CB AD [Analog Devices], EVAL-AD7327CB Datasheet - Page 27

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

If a change to one of the range registers is required during a
sequence, it is necessary to first stop the sequence by writing to
the control register and setting Seq1 to 0 and Seq2 to 0. Next,
the write to the range register should be completed to change
the required range. The previously selected sequence should
then be initiated again by writing to the control register and
setting Seq1 to 0 and Seq2 to 1. The ADC converts the first
channel in the sequence.
The AD7327 can be configured to convert a sequence of
consecutive channels (see Figure 45). This sequence begins by
converting on Channel 0 and ends with a final channel as
selected by Bit ADD2 to Bit ADD0 in the control register. In
this configuration, there is no need for a write to the sequence
register. To operate the AD7327 in this mode, set Seq1 to 1 and
Seq2 to 0, and then select the final channel in the sequence by
programming Bit ADD2 to Bit ADD0 in the control register.
CS
CS
CS
CS
CS
DIN: WRITE TO RANGE REGISTER 1 TO SELECT THE RANGE
DIN: WRITE TO RANGE REGISTER 2 TO SELECT THE RANGE
DIN: WRITE TO CONTROL REGISTER TO SELECT THE FINAL
CHANNEL IN THE CONSECUTIVE SEQUENCE, SET Seq1 = 1
AND Seq2 = 0. SELECT OUTPUT CODING FOR SEQUENCE.
DIN: WRITE BIT = 0 OR DIN LINE HELD LOW TO CONTINUE
DIN: WRITE BIT = 0 OR DIN LINE HELD LOW TO CONTINUE
CS
DOUT: CONVERSION RESULT FROM CHANNEL 0, ±10V
THROUGH SEQUENCE OF CONSECUTIVE CHANNELS.
DOUT: CONVERSION RESULT FROM CHANNEL 0,
DOUT: CONVERSION RESULT FROM CHANNEL 0,
DOUT: CONVERSION RESULT FROM CHANNEL 0,
DOUT: CONVERSION RESULT FROM CHANNEL 1,
TO CONVERT THROUGH THE SEQUENCE OF
Figure 45. Flowchart for Consecutive Sequence of Channels
RANGE SELECTED IN RANGE REGISTER 1,
RANGE SELECTED IN RANGE REGISTER 1,
RANGE SELECTED IN RANGE REGISTER 1.
RANGE SELECTED IN RANGE REGISTER 1.
FOR ANALOG INPUT CHANNELS.
FOR ANALOG INPUT CHANNELS.
FROM CHANNEL IN SEQUENCE.
RANGE, SINGLE-ENDED MODE.
SEQUENCE, Seq1 = 0, Seq2 = 0.
DOUT: CONVERSION RESULT
CONSECUTIVE CHANNELS.
DIN: WRITE TO CONTROL
REGISTER TO STOP THE
SINGLE-ENDED MODE.
SINGLE-ENDED MODE.
A SEQUENCE.
POWER ON.
STOPPING
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Once the control register is configured to operate the AD7327
in this mode, the DIN line can be held low or the write bit can
be set to 0. To return to traditional multichannel operation, a
write to the control register to set Seq1 to 0 and Seq2 to 0 is
necessary.
When Seq1 and Seq2 are both set to 0, or when both are set
to 1, the AD7327 is configured to operate in traditional multi-
channel mode, where a write to the Channel Address Bit ADD2
to Bit ADD0 in the control register selects the next channel for
conversion.
ON CONSECUTIVE SEQUENCE
CONTINUOUSLY CONVERT
OF CHANNELS.
DIN TIED LOW/WRITE BIT = 0.
AD7327