Datasheet

Conditional Transfer
The event input is used to trigger a conditional transfer on peripherals with pending transfer requests. As
example, this type of event can be used for peripheral-to-peripheral transfers, where one peripheral is the
source of event and the second peripheral is the source of the trigger.
Each peripheral trigger is stored internally when the event is received. When the peripheral trigger is
stored internally, the Channel Pending status bit is set (CHSTATUS.PEND), the respective Pending
Channel n Bit in the Pending Channels register is set (PENDCH.PENDCHn), and the event is
acknowledged. A software trigger will now trigger a transfer.
The figure below shows an example where conditional event is enabled with peripheral beat trigger
requests.
Figure 22-14. Conditional Event with Burst Peripheral Triggers
BURST BURST
Event
Peripheral Trigger
PENDCHn
Data Transfer
Block Transfer
Conditional Block Transfer
The event input is used to trigger a conditional block transfer on peripherals.
Before starting transfers within a block, an event must be received. When received, the event is
acknowledged when the block transfer is completed. A software trigger will trigger a transfer.
The figure below shows an example where conditional event block transfer is started with peripheral beat
trigger requests.
Figure 22-15. Conditional Block Transfer with Burst Peripheral Triggers
BURST
BURST
Block Transfer
BURST BURST
Block Transfer
Data Transfer
Peripheral Trigger
Event
PENDCHn
Channel Suspend
The event input is used to suspend an ongoing channel operation. The event is acknowledged when the
current AHB access is completed. For further details on Channel Suspend, refer to 22.6.3.3 Channel
Suspend.
SAM D5x/E5x Family Data Sheet
DMAC – Direct Memory Access Controller
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 392