mc68hc908mr32 Freescale Semiconductor, Inc, mc68hc908mr32 Datasheet - Page 115

• Manufacturer Part Number: mc68hc908mr32
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 12
Pulse-Width Modulator for Motor Control (PWMMC)
12.1 Introduction
This section describes the pulse-width modulator for motor control (PWMMC, version A). The PWM
module can generate three complementary PWM pairs or six independent PWM signals. These
PWM signals can be center-aligned or edge-aligned. A block diagram of the PWM module is shown in
Figure
A12-bit timer PWM counter is common to all six channels. PWM resolution is one clock period for
edge-aligned operation and two clock periods for center-aligned operation. The clock period is dependent
on the internal operating frequency (f
edge-aligned operation is 125 ns (f
250 ns (f
When generating complementary PWM signals, the module features automatic dead-time insertion to the
PWM output pairs and transparent toggling of PWM data based upon sensed motor phase current
polarity.
A summary of the PWM registers is shown in
12.2 Features
Features of the PWMMC include:
Freescale Semiconductor
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Three complementary PWM pairs or six independent PWM signals
Edge-aligned PWM signals or center-aligned PWM signals
PWM signal polarity control
20-mA current sink capability on PWM pins
Manual PWM output control through software
Programmable fault protection
Complementary mode featuring:
–
–
12-2.
OP
Dead-time insertion
Separate top/bottom pulse width correction via current sensing or programmable software bits
= 8 MHz).
MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1
OP
OP
= 8 MHz). The highest resolution for center-aligned operation is
) and a programmable prescaler. The highest resolution for
Figure
12-3.
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