Datasheet

Pulse Width Modulator

PWM Register Descriptions

MC68HC912DT128A — Rev 4.0 Technical Data

MOTOROLA Pulse Width Modulator 233

PWPRES is a free-running 7-bit counter. Read anytime. Write only in

special mode (SMOD = 1).

Read and write anytime. A write will cause the scaler counter PWSCNT0

to load the PWSCAL0 value unless in special mode with DISCAL = 1 in

the PWTST register.

PWM channels 0 and 1 can select clock S0 (scaled) as its input clock by

setting the control bit PCLK0 and PCLK1 respectively. Clock S0 is

generated by dividing clock A by the value in the PWSCAL0 register + 1

and dividing again by two. When PWSCAL0 = $FF, clock A is divided by

256 then divided by two to generate clock S0.

PWSCNT0 is a down-counter that, upon reaching $00, loads the value

of PWSCAL0. Read any time.

PWPRES — PWM Prescale Counter $0043

Bit 7 6 5 4 3 2 1 Bit 0

0 Bit 6 5 4 3 2 1 Bit 0

RESET: 0 0 0 0 0 0 0 0

PWSCAL0 — PWM Scale Register 0 $0044

Bit 7 6 5 4 3 2 1 Bit 0

RESET: 0 0 0 0 0 0 0 0

PWSCNT0 — PWM Scale Counter 0 Value $0045

Bit 7 6 5 4 3 2 1 Bit 0

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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