Freescale Semiconductor
Application Note
AN2701
Rev. 0, 10/2004
PWM Generation with the HC08
Timer
by: Alban Rampon
8/16-bit Division
East Kilbride
Introduction
All HC08 microcontrollers (MCUs) include at least one timer module (TIM). This module is very useful for
generating or capturing time-dependent signals.
The data sheet describes what the timer module is capable of and how to use it.
This application note gives further explanation of how the TIM behaves in the following situations.
•
•
•
Unbuffered pulse width modulation (PWM) signal generation
Rolling PWM generation
Timer activity during Break and software interrupts
PWM signals are used in many applications from dimmers (duty cycle variation gives more/less light from
LEDs) to IR transceivers (modulation/demodulation).
An example illustrating rolling generation is included, with sample code, in the appendix at the end of this
document.
© Freescale Semiconductor, Inc., 2004. All rights reserved.
FREESCALE [ FREESCALE SEMICONDUCTOR, INC ]
