10.4.5 Reset-Synchronized PWM Mode
In reset-synchronized PWM mode channels 3 and 4 are combined to produce three pairs of
complementary PWM waveforms, all having one waveform transition point in common.
When reset-synchronized PWM mode is selected TIOCA
3
, TIOCB
3
, TIOCA
4
, TOCXA
4
,
TIOCB
4
, and TOCXB
4
automatically become PWM output pins, and TCNT3 functions as an up-
counter.
Table 10-5 lists the PWM output pins. Table 10-6 summarizes the register settings.
Table 10-5 Output Pins in Reset-Synchronized PWM Mode
Channel
Output Pin
Description
3
TIOCA
3
PWM output 1
TIOCB
3
PWM output 1´ (complementary waveform to PWM output 1)
4
TIOCA
4
PWM output 2
TOCXA
4
PWM output 2´ (complementary waveform to PWM output 2)
TIOCB
4
PWM output 3
TOCXB
4
PWM output 3´ (complementary waveform to PWM output 3)
Table 10-6 Register Settings in Reset-Synchronized PWM Mode
Register
Setting
TCNT3
Initially set to H'0000
TCNT4
Not used (operates independently)
GRA3
Specifies the count period of TCNT3
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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