26.6.20 Channel Control B

This register affects the DMA channel that is selected in the Channel ID register (CHID.ID).
Name: CHCTRLB
Offset: 0x44
Reset: 0x00000000
Property: RW

Bit 3130292827262524 
       CMD[1:0] 
Access RWRW 
Reset 00 
Bit 2322212019181716 
 TRIGACT[1:0]       
Access RWRW 
Reset 00 
Bit 15141312111098 
 TRIGSRC[7:0] 
Access RWRWRWRWRWRWRWRW 
Reset 00000000 
Bit 76543210 
 LVL[2:0]EVOEEVIEEVACT[2:0] 
Access RWRWRWRWRWRWRWRW 
Reset 00000000 

Bits 25:24 – CMD[1:0] Software Command

These bits define the software commands. Refer to and .

These bits are not enable-protected.

ValueNameDescription
0x0NOACTNo action
0x1SUSPENDChannel suspend operation
0x2RESUMEChannel resume operation
0x3-Reserved
ValueNameDescription
0x0NOACTNo action
0x1SUSPENDChannel suspend operation
0x2RESUMEChannel resume operation

Bits 23:22 – TRIGACT[1:0] Trigger Action

These bits define the trigger action used for a transfer.

ValueNameDescription
0x0BLOCKOne trigger required for each block transfer
0x1-Reserved
0x2BEATOne trigger required for each beat transfer
0x3TRANSACTIONOne trigger required for each transaction
ValueNameDescription
0x0BLOCKOne trigger required for each block transfer
0x2BEATOne trigger required for each beat transfer
0x3TRANSACTIONOne trigger required for each transaction

Bits 15:8 – TRIGSRC[7:0] Trigger Source

These bits define the peripheral trigger which is source of the transfer. For additional information on trigger selection and trigger modes, refer to and CHCTRLB.TRIGACT.

Refer to the table for finding out the value corresponding to each module trigger source.

Important: Refer to the for the list of peripherals and peripheral instances present in each variant.
ValueNameDescription
PERIPHERALPeripheral trigger n selection
0x00DISABLEOnly software/event triggers

Bits 7:5 – LVL[2:0] Channel Arbitration Level

These bits define the arbitration level used for the DMA channel, where a high level has priority over a low level. For additional information on arbitration schemes, refer to the .

These bits are not enable-protected.

ValueNameDescription
0x0LVL0Channel Priority Level 0
0x1LVL1Channel Priority Level 1
0x2LVL2Channel Priority Level 2
0x3LVL3Channel Priority Level 3

Bit 4 – EVOE Channel Event Output Enable

This bit indicates if the Channel event generation is enabled. The event will be generated for every condition defined in the descriptor Event Output Selection (.EVOSEL).

This bit is available only for the 4 least significant DMA channels. Refer to table: User Multiplexer Selection and Event Generator Selection of the Event System for details.

ValueDescription
0Channel event generation is disabled.
1Channel event generation is enabled.

Bit 3 – EVIE Channel Event Input Enable

This bit is available only for the 4 least significant DMA channels. Refer to table: User Multiplexer Selection and Event Generator Selection of the Event System for details.

ValueDescription
0Channel event action will not be executed on any incoming event.
1Channel event action will be executed on any incoming event.

Bits 2:0 – EVACT[2:0] Event Input Action

These bits define the event input action, as shown below. The action is executed only if the corresponding EVIE bit in the CHCTRLB register of the channel is set.

These bits are available only for the 4 least significant DMA channels. Refer to table: User Multiplexer Selection and Event Generator Selection of the Event System for details.

ValueNameDescription
0x0NOACTNo action
0x1TRIGNormal Transfer and Conditional Transfer on Strobe trigger
0x2CTRIGConditional transfer trigger
0x3CBLOCKConditional block transfer
0x4SUSPENDChannel suspend operation
0x5RESUMEChannel resume operation
0x6SSKIPSkip next block suspend action
0x7-Reserved
ValueNameDescription
0x0NOACTNo action
0x1TRIGTransfer and periodic transfer trigger
0x2CTRIGConditional transfer trigger
0x3CBLOCKConditional block transfer
0x4SUSPENDChannel suspend operation
0x5RESUMEChannel resume operation
0x6SSKIPSkip next block suspend action