ADC Configuration Examples
314
SNIU028A – February 2016 – Revised April 2016
Copyright © 2016, Texas Instruments Incorporated
ADC12 Overview
The maximum number of conversions is set to 5 and the sequence select register is set as shown in the
following table Note for convenience, I1, I2, ...etc are used to represent the sequence select value.
Bits
Field Name
Channel Select Value
SEQCHSEL0
4:0
SEQ00
I
1
9:5
SEQ01
I
2
14:10
SEQ02
I
3
SEQCHSEL1
Bits
Field Name
Channel Select Value
4:0
SEQ03
I
4
9:5
SEQ04
I
5
14:10
SEQ05
I
6
SEQCHSEL2
Bits
Field Name
Channel Select Value
4:0
SEQ06
X
9:5
SEQ07
X
14:10
SEQ08
X
SEQCHSEL3
Bits
Field Name
Channel Select Value
4:0
SEQ09
X
9:5
SEQ10
X
14:10
SEQ11
X
Once reset and initialized, the sequencer waits for an external trigger. At the 1st trigger, six conversions
(sequence select values of SEQ00(I
1
), SEQ01(I
2
), SEQ02(I
3
), SEQ03(I
4
), SEQ04(I
5
) and SEQ05(I
6
)) are
performed. At the end of the auto-conversion session, the ADC result registers have the following values:
Buffer Registers
ADC Conversion Result
RESULT-00
I
1
RESULT-01
I
2
RESULT-02
I
3
RESULT-03
I
4
RESULT-04
I
5
RESULT-05
I
6
Note at this point, the sequencer remains at its current state waiting for another trigger.
8.16.5 Start/Stop Operation (External Trigger)
Here the sequencer is synchronized to the start of an external trigger. At the end of the conversion
sequence, when the maximum number of conversions has occurred, the sequencer performs only a single
sweep of conversions.
Requirement: Automatically convert 4 voltages (V1/V2/V3/V4) every 100us synchronized to an external
trigger. In this example, the maximum number of conversions is set to 3 and the sequence select registers
are set as follows:
Bits
Field Name
Channel Select Value
SEQCHSEL0
4:0
SEQ00
V
1
9:5
SEQ01
V
2
14:10
SEQ02
V
3
SEQCHSEL1
Bits
Field Name
Channel Select Value
4:0
SEQ03
V
4
9:5
SEQ04
X
14:10
SEQ05
X