8.2.2 Trigger Operation
Each SOC can be configured to start on one of many input triggers. Multiple SOCs can be configured for the
same channel if desired. Following is a list of the available input triggers:
• Software
• CPU Timers 0/1/2 interrupts
• XINT2 SOC
• ePWM1-8 SOCA and SOCB
See the ADCSOCxCTL register bit definitions for the configuration details of these triggers.
Additionally ADCINT1 and ADCINT2 can be fed back to trigger another conversion. This configuration is
controlled in the ADCINTSOCSEL1/2 registers. This mode is useful if a continuous stream of conversions is
desired. See
for information on the ADC interrupt signals.
8.2.3 Channel Selection
Each SOC can be configured to convert any of the available ADCIN input channels. When an SOC is configured
for sequential sampling mode, the four bit CHSEL field of the ADCSOCxCTL register defines which channel to
convert. When an SOC is configured for simultaneous sampling mode, the most significant bit of the CHSEL field
is dropped and the lower three bits determine which pair of channels are converted.
ADCINA0 is shared with VREFHI, and therefore cannot be used as a variable input source when using external
reference voltage mode. See
for details on this mode.
8.3 ONESHOT Single Conversion Support
This mode will allow you to perform a single conversion on the next triggered SOC in the round robin scheme.
The ONESHOT mode is only valid for channels present in the round robin wheel. Channels which are not
configured for triggered SOC in the round robin scheme will get priority based on contents of the SOCPRIORITY
field in the ADCSOCPRIORITYCTL register.
Incoming ADC Trigger
ONESHOT ! = 0
Process sampling
with current ADC
state machine
Beginning with current Round Robin
Pointer, only set the SOCFLG
bit for next triggered sequence
No
Yes
Figure 8-4. ONESHOT Single Conversion
The effect of ONESHOT mode on Sequential Mode and Simultaneous Mode is explained below.
Sequential mode:
Only the next active SOC in RR mode (one up from current RR pointer) will be allowed to
generate SOC; all other triggers for other SOC slots will be ignored.
Analog-to-Digital Converter (ADC)
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
TMS320x2806x Microcontrollers
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Copyright © 2022 Texas Instruments Incorporated
Summary of Contents for TMS320 2806 Series
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