Datasheet

Channel Resume
The event input is used to resume a suspended channel operation. The event is acknowledged as soon
as the event is received and the Channel Suspend Interrupt Flag (CHINTFLAG.SUSP) is cleared. For
further details refer to 22.6.3.3 Channel Suspend.
Skip Next Block Suspend
This event can be used to skip the next block suspend action. If the channel is suspended before the
event rises, the channel operation is resumed and the event is acknowledged. If the event rises before a
suspend block action is detected, the event is kept until the next block suspend detection. When the block
transfer is completed, the channel continues the operation (not suspended) and the event is
acknowledged.
Increase priority
This event can be used to increase a channel priority and to request higher quality of service (QOS),
when critical transfers must be done. When the event is detected, the channel will have the highest
priority and the output Quality of Service value is internally forced to the maximum value. The event is
acknowledged when the trigger action execution is completed. When acknowledged, the channel will
recover its initial priority level and quality of service settings.
22.6.3.6 Event Output Selection
The event output selections are available only for channels supporting event outputs.
The Channel Event Output Enable can be set in the corresponding Channel n Event Control register
(CHEVCTRL.EVOE). The Event Output Mode bits in Channel n Event Control register
(CHEVCTRL.EVOMODE) selects the event type the channel should generate.
The transfer events (CHEVCTRL.EVOMODE = DEFAULT) are strobe events and their duration is one
CLK_DMAC_AHB clock period. The transfer event type selection is available in each Descriptor Block
Control location (BTCTRL.EVOSEL). Block or burst event output generation is supported.
The trigger action event (CHEVCTRL.EVOMODE = TRIGACT) is a level, active while the trigger action
execution is not completed.
Block event output
When the block event output is selected, an event strobe is generated when the block transfer is
completed. The pulse width of a block event output from a channel is one AHB clock cycle. It is also
possible to use this event type to generate an event when the transaction is complete. For this type of
application, the block event selection must be set in the last transfer descriptor only, as shown below.
Figure 22-16. Block Event Output Generation
BURST
BURST
Block Transfer
Data Transfer
BURST BURST
Block Transfer
Event Output
Burst event output
When the burst event output is selected, an event strobe is generated when each burst transfer within the
corresponding block is completed. The pulse width of a burst event output from a channel is one AHB
clock cycle. The figure below shows an example where the burst event output is set in the second
descriptor of a linked list.
SAM D5x/E5x Family Data Sheet
DMAC – Direct Memory Access Controller
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 393