The Counter period is changed by writing a
new TOP value to the Period register (TCAn.PER).
No Buffering: If double buffering is not
used, any period update is immediate.
Figure 20-6. Changing the Period Without
Buffering
A counter wrap-around
can occur in any mode of operation when up-counting without buffering.
This is due to the fact that the TCAn.CNT and TCAn.PER registers are
continuously compared: if a new TOP value is written to TCAn.PER that
is lower than the current TCAn.CNT, the counter will wrap first, before
a compare match happens.Figure 20-7. Unbuffered
Dual-Slope Operation
With Buffering: When double
buffering is used, the buffer can be written at any time and still maintain correct
operation. The TCAn.PER is always updated on the UPDATE condition, as shown for dual-slope
operation in the figure below. This prevents wrap-around and the generation of odd
waveforms.Figure 20-8. Changing the Period Using
Buffering
The online versions of the documents are provided as a courtesy. Verify all content and data in the device’s PDF documentation found on the device product page.
