AD7324 Analog Devices, AD7324 Datasheet - Page 25

• Manufacturer Part Number: AD7324
• Description: Software Selectable True Bipolar Input, 4-Channel, 12-Bit Plus Sign A/D Converter
• Manufacturer: Analog Devices

Specifications of AD7324

• Resolution (bits): 13bit
• # Chan: 4
• Sample Rate: 1MSPS
• Interface: Ser,SPI
• Analog Input Type: Diff-Bip,Diff-Uni,SE-Uni
• Ain Range: Bip (Vref),Bip (Vref) x 2,Bip (Vref) x 4,Bip 10V,Bip 2.5V,Bip 5.0V,Uni (Vref) x 4,Uni 10V
• Adc Architecture: SAR
• Pkg Type: SOP

SEQUENCER OPERATION
The AD7324 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 AD7324 register to operate in
sequence mode.
After power-up, all of the three 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
register is required. This is shown in the first serial transfer 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
Figure 44. Programmable Sequence Flowchart
A SEQUENCE.
DIN: TIE DIN LOW/WRITE BIT = 0 TO CONTINUE TO CONVERT
DIN: WRITE TO RANGE REGISTER TO SELECT THE RANGE
STOPPING
DOUT: CONVERSION RESULT FROM FIRST CHANNEL IN
DIN: WRITE TO SEQUENCE REGISTER TO SELECT THE
DIN: WRITE TO SEQUENCE REGISTER TO SELECT THE
DOUT: CONVERSION RESULT FROM CHANNEL 0, ±10V
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,
ANALOG INPUT CHANNELS TO BE INCLUDED IN
SINGLE-ENDED MODE, RANGE SELECTED IN
SINGLE-ENDED MODE, RANGE SELECTED IN
Rev. A | Page 25 of 36
THROUGH THE SEQUENCE OF CHANNELS.
SELECTING A NEW SEQUENCE.
FOR EACH ANALOG INPUT CHANNEL.
RANGE, SINGLE-ENDED MODE.
SEQUENCE, Seq1 = 0, Seq2 = 1.
THE FIRST SEQUENCE.
RANGE REGISTER.
RANGE REGISTER.
NEW SEQUENCE.
THE SEQUENCE.
THE SEQUENCE.
POWER ON.
This initial serial transfer is 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 AD7324 continues to convert the selected
sequence without interruption provided that 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.
AD7324