24.8.5 Quick Start Guide for Using DMA with TC

The supported kit list:

  • SAM D21/R21/D11/L21/L22/DA1/C21 Xplained Pro

In this use case, the TC will be used to generate a PWM signal. Here the pulse width is set to one quarter of the period. Once the counter value matches the values in the Compare/Capture Value register, an event will be tiggered for a DMA memory to memory transfer. The TC module will be set up as follows:

  • GCLK generator 0 (GCLK main) clock source

  • 16-bit resolution on the counter

  • No prescaler

  • Normal PWM wave generation

  • GCLK reload action

  • Don't run in standby

  • No inversion of waveform output

  • No capture enabled

  • Count upward

  • Don't perform one-shot operations

  • No event input enabled

  • No event action

  • No event generation enabled

  • Counter starts on 0

  • Capture compare channel 0 set to 0xFFFF/4

The DMA module is configured for:

  • Move data from memory to memory

  • Using peripheral trigger of TC6 Match/Compare 0

  • Using DMA priority level 0