RX610 Group
12. DMA Controller (DMAC)
R01UH0032EJ0120 Rev.1.20
Page 327 of 1006
Feb 20, 2013
12.3.4
Starting DMA Transfer
Setting the DEN bit in DMCRE of DMACm to 1 (DMA transfer enabled) and setting the DMST bit in DMSCNT to 1
(DMAC start) enable DMA transfer of channel m (m = 0 to 3).
When DMA transfer requests are generated, channel arbitration is made where a DMA transfer request of higher-priority
channel is accepted and DMA transfer of the channel starts. When a DMA transfer request is accepted and DMA transfer
starts, the DASTSm flag in DMASTS is set to 1 (data transfer is in progress).
12.3.5
Ending DMA Transfer
When the DMCBC register value of DMACm is decreased to 0000000h, DMA transfer of channel m (m = 0 to 3) ends
and the DMAC performs the following processing.
•
The DEDETm flag in DMEDET is set to 1 (DMA transfer end detected).
•
When the DINTMm bit in DMICNT is 1 (interrupts enabled), a DMAm interrupt request (DMTENDm) request
occurs.
•
When the value of the ECLR bit in DMCRC for DMACm is "1" causing the DEN bit in DMCRE for DMACm to be
cleared to "0" on completion of DMA transfer, subsequent DMA transfer on channel m does not proceed once the
value of the DEN bit has become "1" (disabling DMA transfer).
•
When the reload functions are used, reload register values are reloaded to the current registers respectively.