Datasheet

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

RESET: 0 0 0 0 0 0 0 0

PWSCNT1 — PWM Scale Counter 1 Value $0047

Bit 7 6 5 4 3 2 1 Bit 0

RESET: 0 0 0 0 0 0 0 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 0 0 0 0 0 0 0

Frees

cale Semiconductor,

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

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