23.3.4.3 Changing the Period

The Counter period is changed by writing a new TOP value to the Period (TCEn.PER) register.

Changing the Period Without Buffering

When not using Double Buffering, any period update is immediate.

Figure 23-5. Changing the Period Without Buffering
A counter wraparound can occur in any mode of operation when up-counting without buffering. This happens because the TCEn.CNT and TCEn.PER registers are continuously compared. If a new TOP value is written to TCEn.PER that is lower than current TCEn.CNT, the counter will wrap first before a compare match happens.
Figure 23-6. Unbuffered Dual-Slope Operation

Changing the Period Using Buffering

When using Double Buffering, the buffer can be written at any time and maintain the correct operation. The TCEn.PER is always updated on the UPDATE condition, as shown for dual-slope operation in the figure below, preventing wrap-around and the generation of odd waveforms.
Figure 23-7. Changing the Period Using Buffering