25.10.1 Channel Control A Register
| Symbol | Description | Symbol | Description | Symbol | Description |
|---|---|---|---|---|---|
| R | Readable bit | HC | Cleared by Hardware | (Grey cell) | Unimplemented |
| W | Writable bit | HS | Set by Hardware | X | Bit is unknown at Reset |
| K | Write to clear | S | Software settable bit | — | — |
| Name: | CHCTRLAk |
| Offset: | 0x50 + k*0x50 [k=0..15] |
| Reset: | 0x00000000 |
| Property: | PAC Write-Protection |
| Bit | 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | |
| RUNSTDBY | |||||||||
| Access | R/W | ||||||||
| Reset | 0 |
| Bit | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | |
| SWFRC | |||||||||
| Access | W | ||||||||
| Reset | 0 |
| Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | |
| LLEN | |||||||||
| Access | R/W/HC | ||||||||
| Reset | 0 |
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| ENABLE | |||||||||
| Access | R/W/HC | ||||||||
| Reset | 0 |
Bit 24 – RUNSTDBY Run in Standby
This bit is used to keep the DMA channel running in Standby mode:
| Value | Description |
|---|---|
| 0 | The channel is halted in standby. |
| 1 | The channel continues to run in standby. Continue module operation in Idle/Sleep mode. |
Bit 16 – SWFRC Software Force Trigger
Write to 1 to issue a start trigger to the channel. Reading this bit always returns 0.
Bit 8 – LLEN Linked List Enable
| Value | Description |
|---|---|
| 0 | Next descriptor loading is disabled for the channel. |
| 1 | DMA will load the next descriptor at address location to by CHNXTk.NXT[31:0] on completion of the current block transfer or if the channel is idle (i.e. CHCTRLAk.ENABLE = 0 and CHSTATk.BLK-BUSY = 0). If CHNXTk.NXT[31:0] = 0xFFFF_FFFF (NULL) the DMA will set the CHINTFk.LL status bit and clear LLEN. No further action takes place. |
Bit 0 – ENABLE Channel Enable
Writing a 1 to ENABLE enables a block transfer. Upon completion or abort of the block transfer the DMA clears ENABLE.
| Value | Description |
|---|---|
| 0 | Disable channel block transfers or suspend block transfer if CHSTATk.BLKBUSY = 1. |
| 1 | Block transfer enabled. The DMA will initiate a block transfer on the start trigger selected by CHCTRLBk.TRIG or a software trigger, CHCTRLAk.SWFRC = 1. |
