One Ramp Mode

In One Ramp Mode, TCD counter counts up until it reaches the CMPBCLR value. Then the TCD cycle is done and the counter restarts from 0x000, beginning a new TCD cycle. The TCD cycle period is

Figure 1. One Ramp Mode
In the figure above, CMPASET < CMPACLR < CMPBSET < CMPBCLR. This is required in One Ramp Mode to avoid overlapping outputs. The figure below is an example where CMPBSET < CMPASET < CMPACLR < CMPBCLR, resulting in an overlap of the outputs.
Figure 2. One Ramp Mode with CMPBSET < CMPASET
If any of the other compare values are bigger than CMPBCLR it will never be triggered when running in One ramp mode. And if The CMPACLR is smaller than the CMPASET value, the clear value will not have any effect.