
Pulse Width Modulator
Technical Data
MC68HC912DT128A — Rev 4.0
234
Pulse Width Modulator
MOTOROLA
Read and write anytime. A write will cause the scaler counter PWSCNT1
to load the PWSCAL1 value unless in special mode with DISCAL = 1 in
the PWTST register.
PWM channels 2 and 3 can select clock S1 (scaled) as its input clock by
setting the control bit PCLK2 and PCLK3 respectively. Clock S1 is
generated by dividing clock B by the value in the PWSCAL1 register + 1
and dividing again by two. When PWSCAL1 = $FF, clock B is divided by
256 then divided by two to generate clock S1.
PWSCNT1 is a down-counter that, upon reaching $00, loads the value
of PWSCAL1. Read any time.
Read and write anytime. A write will cause the PWM counter to reset to
$00.
In special mode, if DISCR = 1, a write does not reset the PWM counter.
PWSCAL1 — PWM Scale Register 1
$0046
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
RESET:
0
PWSCNT1 — PWM Scale Counter 1 Value
$0047
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
RESET:
0
PWCNTx — PWM Channel Counters
Bit 7
6
5
4
3
2
1
Bit 0
PWCNT0
Bit 7
6
5
4
3
2
1
Bit 0
$0048
PWCNT1
Bit 7
6
5
4
3
2
1
Bit 0
$0049
PWCNT2
Bit 7
6
5
4
3
2
1
Bit 0
$004A
PWCNT3
Bit 7
6
5
4
3
2
1
Bit 0
$004B
RESET:
0
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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