SLAZ623AA August 2014 – August 2021 MSP430FR6987
ADC Module
Functional
DMA gets stuck when switching between ADC data transfer trigger types
If the ADC performs a data transfer by the CPU ,e.g. via interrupt or flag polling,
AND
the ADC is then configured for an edge-triggered DMA transfer
THEN
the DMA cannot be triggered and no data transfer will occur.
1. Do not switch between the ADC triggered CPU data transfer and ADC triggered DMA data transfer to avoid this condition. Or,
2. Apply a POR reset to clear the trigger DMA trigger logic inside the ADC. Or,
3. Perform a dummy DMA transfer via level trigger option (DMAxCTL.DMALEVEL=1) to clear ADC trigger logic. In this case, it is recommended to throw out current ADC conversion and ignore the data of the DMA dummy transfer.