Software starts or stops DMA transaction by setting/clearing the DGO bit. The DGO bit is also used to indicate whether a DMA hardware
trigger has been received and a message is in progress.
Important:
- 1.Software start can only occur
when the EN bit is set.
- 2.If the CPU writes to the DGO bit while it is already set, there is no effect on the
system, the DMA will continue to operate normally.