Datasheet

Figure 31-10. Unbuffered Single-Slope Up-Counting Operation
COUNT
MAX
New value written to
PER that is higher
than current COUNT
Counter Wraparound
New value written to
PER that is lower
than current COUNT
"clear" update
"write"
ZERO
Figure 31-11. Unbuffered Single-Slope Down-Counting Operation
COUNT
MAX
New value written to
PER that is higher
than current COUNT
New value written to
PER that is lower
than current COUNT
"reload" update
"write"
ZERO
A counter wraparound can occur in any operation mode when up-counting without buffering, see Figure
31-10. COUNT and TOP are continuously compared, so when a new value that is lower than the current
COUNT is written to TOP, COUNT will wrap before a compare match.
Figure 31-12. Unbuffered Dual-Slope Operation
COUNT
New value written to
PER that is higher
than current COUNT
New value written to
PER that is lower
than current COUNT
"reload" update
"write"
Counter Wraparound
MAX
ZERO
When double buffering is used, the buffer can be written at any time and the counter will still maintain
correct operation. The period register is always updated on the update condition, as shown in Figure
31-13. This prevents wraparound and the generation of odd waveforms.
SAM D21 Family
TCC – Timer/Counter for Control Applications
© 2018 Microchip Technology Inc.
Datasheet Complete
DS40001882D-page 719