DMA Operation

The TC can generate the following DMA requests:

• Overflow (OVF): the request is set when an update condition (overflow, underflow) is detected. The request is cleared on next clock cycle.
• Channel Match or Capture (MCx): for a compare channel, the request is set on each compare match detection and cleared on next clock cycle. For a capture channel, the request is set when valid data is present in CCx register, and cleared when CCx register is read.

When using the TC with the DMA OVF request, the new value will be transferred to the register after the update condition. This means that the value is updated after the DMA and synchronization delay, and if the COUNT value has reached the new value before PER or CCx is updated, a match will not happen.

When using the TC with the DMA MCx request and updating CCx with a value that is lower than the current COUNT when down-counting, or higher than the current COUNT when up-counting, this value could cause a new compare match before the counter overflows. This will trigger the next DMA transfer, update CCx again, and the previous value is disregarded from the output signal WO[x].