MC68HC908LB8_05 Datasheet, PDF (141/234 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Chapter 15
Pulse Width Modulator with Fault Input (PWM)
15.1 Introduction
This section describes the pulse-width modulator with fault input (PWM). The MC68HC908LB8 PWM
module can generate two independent PWM signals. These PWM signals are edge-aligned. A block
diagram of the PWM module is shown in Figure 15-2.
A 12-bit timer PWM counter is common to both channels. PWM resolution is one clock period for
edge-aligned operation. The clock period is dependent on the internal operating frequency (BUSCLK) and
a programmable prescaler.
The highest resolution for edge-aligned operation is 125 ns (BUSCLK = 8 MHz).
A summary of the PWM registers is shown in Figure 15-3.
15.2 Features
Features of the PWMMC include:
• Two independent PWM signals
• Edge-aligned PWM signals
• PWM signal polarity control
• Programmable fault protection
MC68HC908LB8 Data Sheet, Rev. 1
Freescale Semiconductor
141