MC68HC708MP16 Datasheet, PDF (130/398 Pages) Freescale Semiconductor, Inc – Microcontrollers

Pulse Width Modulator for Motor Control (PWMMC)
9.11 Control Logic Block. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
9.11.1 PWM Counter Registers . . . . . . . . . . . . . . . . . . . . . . . . . . 172
9.11.2 PWM Counter Modulo Registers. . . . . . . . . . . . . . . . . . . .173
9.11.3 PWM X Value Registers . . . . . . . . . . . . . . . . . . . . . . . . . . 174
9.11.4 PWM Control Register 1 . . . . . . . . . . . . . . . . . . . . . . . . . . 175
9.11.5 PWM Control Register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . 177
9.11.6 Dead-Time Write-Once Register . . . . . . . . . . . . . . . . . . . .179
9.11.7 PWM Disable Mapping Write-Once Register . . . . . . . . . . 180
9.11.8 Fault Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
9.11.9 Fault Status Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
9.11.10 Fault Acknowledge Register . . . . . . . . . . . . . . . . . . . . . . .185
9.11.11 PWM Output Control Register. . . . . . . . . . . . . . . . . . . . . . 186
9.12 PWM Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
9.2 Introduction
This section describes the pulse width modulator for motor control
(PWMMC, Version A). The MC68HC(7)08MP16 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 9-1.
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_op) and a programmable prescaler.
The highest resolution for edge-aligned operation is 125 ns (f_op = 8
MHz). The highest resolution for center-aligned operation is 250 ns
(f_op = 8 MHz).
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 Figure 9-2.
Technical Data
130
MC68HC708MP16 — Rev. 3.1
Pulse Width Modulator for Motor Control (PWMMC) Freescale Semiconductor