Datasheet

Figure 48-6. Match PWM Operation
COUNT
MAX
CC0
Period (T)
" match"
ZERO
CCx= Zero
CC1
CCx= TOP
" clear" update
WO[1]
The table below shows the Update Counter and Overflow Event/Interrupt Generation conditions in
different operation modes.
Table 48-4. Counter Update and Overflow Event/interrupt Conditions in TC
Name Operation TOP Update Output Waveform OVFIF/Event
On Match On Update Up Down
NFRQ Normal Frequency PER TOP/ ZERO Toggle Stable TOP ZERO
MFRQ Match Frequency CC0 TOP/ ZERO Toggle Stable TOP ZERO
NPWM Single-slope PWM PER TOP/ ZERO See description above. TOP ZERO
MPWM Single-slope PWM CC0 TOP/ ZERO Toggle Toggle TOP ZERO
Related Links
32. PORT - I/O Pin Controller
48.6.2.7 Double Buffering
The Compare Channels (CCx) registers, and the Period (PER) register in 8-bit mode are double buffered.
Each buffer register has a buffer valid bit (CCBUFVx or PERBUFV) in the STATUS register, which
indicates that the buffer register contains a new valid value that can be copied into the corresponding
register. As long as the respective buffer valid status flag (PERBUFV or CCBUFVx) are set to '1', related
syncbusy bits are set (SYNCBUSY.PER or SYNCBUSY.CCx), a write to the respective PER/PERBUF or
CCx/CCBUFx registers will generate a PAC error, and access to the respective PER or CCx register is
invalid.
When the buffer valid flag bit in the STATUS register is '1' and the Lock Update bit in the CTRLB register
is set to '0', (writing CTRLBCLR.LUPD to '1'), double buffering is enabled: the data from buffer registers
will be copied into the corresponding register under hardware UPDATE conditions, then the buffer valid
flags bit in the STATUS register are automatically cleared by hardware.
Note: The software update command (CTRLBSET.CMD=0x3) is acting independently of the LUPD
value.
A compare register is double buffered as in the following figure.
SAM D5x/E5x Family Data Sheet
TC – Timer/Counter
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 1720