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AN4635

Operation modes

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3.4.2

Combining DMA with direct access

The DMA channel is convenient for transmission of data, and it’s power efficient during

reception.

The downside is that in DMA mode the LPUART cannot take advantage of wakeup from

Stop mode. The reason is that after wakeup event the DMA has difficulty picking up on the

ongoing communication. This is a serious disadvantage for all applications that tend to

remain idle for long periods of time.

However the DMA can still be used for transmission and then reception can proceed with

blocking or interrupt approach. In communication systems where incoming messages are

coming in quick succession or predictable timing, the DMA based reception may also be an

efficient option.