38.6.2.2 Enabling a DMA Channel

Follow the steps below to enable a DMA channel:

  1. Check the status of the channel by reading the CHXCHSR register.
  2. Write the channel descriptor (DSCR) structure in the system memory by writing DSCR.CHXADDR Frame base address, DSCR.CHXCTRL channel control and DSCR.CHXNEXT next descriptor location.
  3. If more than one descriptor is expected, the field DFETCH of DSCR.CHXCTRL is set to ‘1’ to enable the descriptor fetch operation.
  4. Write the DSCR.CHXNEXT register with the address location of the descriptor structure and set DFETCH field of the DSCR.CHXCTRL register to ‘1’.
  5. Enable the relevant channel by writing one to the CHEN field of the CHXCHER register.
  6. An interrupt may be raised if unmasked when the descriptor has been loaded.