ADC Module DMA Requests
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SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
Analog To Digital Converter (ADC) Module
19.6 ADC Module DMA Requests
This section describes the capabilities of the ADC module to take advantage of the Platform DMA
controller module. The ADC module can generate a DMA request under two conditions:
19.6.1 DMA Request for Each Conversion Result Written to the Results’ Memory
In this mode, the ADC module will generate the first DMA request as soon as a conversion result gets
written to the group’s results’ memory. Subsequent writes to the results’ memory will cause DMA requests
to be generated. This mode allows a smaller amount of ADC results’ memory to suffice for an application.
This DMA request generation is enabled by setting the group’s DMA_EN bit in the group’s DMA control
register. The BLK_XFER bit in this register must be left cleared (default) if a DMA request is desired to be
generated for new results getting written to the results’ memory.
19.6.2 DMA Request for a Fixed Number of Conversion Results
This mode is enabled by setting both the group’s DMA_EN and the group’s BLK_XFER bits in the group’s
DMA control registers.
In this mode, a DMA request will be generated for a specified number of conversion results being
available in the group’s results’ memory. The number of conversion results desired are configured using
the group’s BLOCKS field in the control registers.
For example, if the BLOCK count is configured for 10, then ADC module will generate a DMA request at
the end of 10th conversion. DMA controller should complete reading out 10 data before next set of 10
conversions complete.
NOTE:
Usage of Block DMA transfers with Threshold Interrupts
It is not recommended to enable the block DMA transfers for a group at the same time as the
group threshold interrupt. The group’s BLOCKS field is essentially the same as the group’s
THRESHOLD field in the group’s interrupt control register described in
.
