Atmel Xplained Pro Evaluation Kit ATSAMD20-XPRO ATSAMD20-XPRO Data Sheet

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Atmel | SMART SAM D20 [DATASHEET]

Atmel-42129K–SAM-D20_datasheet–06/2014

To configure a channel, the Channel register must be written in a single 32-bit write.

It is possible to read out the configuration of a channel by first selecting the channel by writing to CHANNEL.CHANNEL 
using a, 8-bit write, and then performing a read of the CHANNEL register.

The event generator is selected by writing to the Event Generator bit group in the Channel register (CHANNEL.EVGEN).

A full list of selectable generators can be found in the CHANNEL register description. Refer to 

The channels are not connected to any of the event generators (CHANNEL.EVGEN = 0x00) by default.

There are three different ways to propagate the event provided by an event generator:

z

Asynchronous path

z

Synchronous path

z

Resynchronized path

The path is selected by writing to the Path Selection bit group in the Channel register (CHANNEL.PATH).

When using the asynchronous path, the events are propagated from the event generator to the event user with no 
intervention from the event system. This means that if the GCLK_EVSYS_x for the channel used is inactive, the event 
will still be propagated to the user.

Events propagated in the asynchronous path cannot generate any interrupts, and no channel status bits will indicate the 
state of the channel. No edge detection is available; this must be handled in the event user.

When the event generator and the event user share the same generic clock, using the asynchronous path will propagate 
the event with the least amount of latency.

CHANNEL.SWEVT

CHANNEL m

CHANNEL.EVGEN

PERIPHERALS

SLEEPWALKING 

DETECTOR

CLOCK_REQUEST_m

CHANNEL.PATH

RESYNC

EDGE 

DETECTION

CHANNEL.EDGSEL

CHANNEL_EVT_m

GENERATORS EVENTS

SYNC

ASYNC