22.3.3.2.3 Four Ramp Mode

In Four Ramp mode, the TCD cycle follows this pattern:
  1. A TCD cycle begins with the TCD counter counting up from zero until it reaches the CMPASET value, and resets to zero.
  2. The counter counts up until it reaches the CMPACLR value, and resets to zero.
  3. The counter counts up until it reaches the CMPBSET value, and resets to zero.
  4. The counter counts up until it reaches the CMPBCLR value, and ends the TCD cycle by resetting to zero.
The TCD cycle period is given by:
T TCD_cycle = ( CMPASET + 1 ) + ( CMPACLR + 1 ) + ( CMPBSET + 1 ) + ( CMPBCLR + 1 ) f CLK_TCD_CNT
Figure 22-6. Four Ramp Mode

There are no restrictions regarding the compare values, because there are no dependencies between them.

In Four Ramp mode, it is not possible to get overlapping outputs without using the override feature.