10.4.6 Complementary PWM Mode
In complementary PWM mode channels 3 and 4 are combined to output three pairs of
complementary, non-overlapping PWM waveforms.
When complementary PWM mode is selected TIOCA
3
, TIOCB
3
, TIOCA
4
, TOCXA
4
, TIOCB
4
,
and TOCXB
4
automatically become PWM output pins, and TCNT3 and TCNT4 function as
up/down-counters.
Table 10-7 lists the PWM output pins. Table 10-8 summarizes the register settings.
Table 10-7 Output Pins in Complementary PWM Mode
Channel
Output Pin
Description
3
TIOCA
3
PWM output 1
TIOCB
3
PWM output 1´ (non-overlapping complementary waveform to PWM
output 1)
4
TIOCA
4
PWM output 2
TOCXA
4
PWM output 2´ (non-overlapping complementary waveform to PWM
output 2)
TIOCB
4
PWM output 3
TOCXB
4
PWM output 3´ (non-overlapping complementary waveform to PWM
output 3)
Table 10-8 Register Settings in Complementary PWM Mode
Register
Setting
TCNT3
Initially specifies the non-overlap margin (difference to TCNT4)
TCNT4
Initially set to H'0000
GRA3
Specifies the upper limit value of TCNT3 minus 1
GRB3
Specifies a transition point of PWM waveforms output from TIOCA
3
and TIOCB
3
GRA4
Specifies a transition point of PWM waveforms output from TIOCA
4
and TOCXA
4
GRB4
Specifies a transition point of PWM waveforms output from TIOCB
4
and TOCXB
4
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