Four Ramp Mode

In Four Ramp Mode the TCD cycle is following 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 from zero until it reaches the CMPACLR value, and resets to zero.
3.The Counter counts up from zero until it reaches the CMPBSET value, and resets to zero.
4.The Counter counts up from zero until it reaches the CMPBCLR value, and ends the TCD cycle by resetting to zero.

The TCD cycle period is given by

TTCD_cycle=(CMPASET+1+CMPACLR+1+CMPBSET+1+CMPBCLR+1)fCLK_TCD_CNT

Figure 1. Four Ramp Mode

There are no restrictions on the compare values compared to each others.

In Four Ramp Mode it is not possible to get overlapping outputs.