Hitachi H8/3048 Hardware Manual page 368

Setup Procedure for Complementary PWM Mode: Figure 10-33 shows a sample procedure for
setting up complementary PWM mode.
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Complementary PWM mode
Stop counting
Select counter clock
Select complementary
PWM mode
Set TCNTs
Set general registers
Start counters
Complementary PWM mode
Note: After exiting complementary PWM mode, to resume operating in complementary
PWM mode, follow the entire setup procedure from step 1 again.
Figure 10-33 Setup Procedure for Complementary PWM Mode (Example)
1. Clear bits STR3 and STR4 to 0 in
TSTR to halt the timer counters.
Complementary PWM mode must be
set up while TCNT3 and TCNT4 are
1 halted.
2. Set bits TPSC2 to TPSC0 in TCR to
select the same counter clock source
for channels 3 and 4. If an external
2
clock source is selected, select the
external clock edge(s) with bits
CKEG1 and CKEG0 in TCR. Do not
select any counter clear source
3
with bits CCLR1 and CCLR0 in TCR.
3. Set bits CMD1 and CMD0 in TFCR
to select complementary PWM mode.
4
TIOCA , TIOCB
3
TOCXA , and TOCXB
4
become PWM output pins.
5 4. Clear TCNT4 to H'0000. Set the
non-overlap margin in TCNT3. Do not
set TCNT3 and TCNT4 to the same
value.
6
5. GRA3 is the waveform period
register. Set the upper limit value of
TCNT3 minus 1 in GRA3. Set
transition times of the PWM output
waveforms in GRB3, GRA4, and
GRB4. Set times within the compare
match range of TCNT3 and TCNT4.
≤
T X (X: initial setting of GRB3,
GRA4, or GRB4. T: initial setting of
TCNT3)
6. Set bits STR3 and STR4 in TSTR to
1 to start TCNT3 and TCNT4.
356
, TIOCA , TIOCB ,
3 4 4
automatically
4