Motorola MCF5281 用户手册

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Chapter 20.  General Purpose Timer Modules (GPTA and GPTB)  

20-1

The MCF5282 has two 4-channel general purpose timer modules (GPTA and GPTB). Each
consists of a 16-bit counter driven by a 7-stage programmable prescaler. 

A timer overflow function allows software to extend the timing capability of the system
beyond the 16-bit range of the counter. Each of the four timer channels can be configured
for input capture, which can capture the time of a selected transition edge, or for output
compare, which can generate output waveforms and timer software delays. These functions
allow simultaneous input waveform measurements and output waveform generation.

Additionally, one of the channels, channel 3, can be configured as a 16-bit pulse
accumulator that can operate as a simple event counter or as a gated time accumulator. The
pulse accumulator uses the GPT channel 3 input/output pin in either event mode or gated
time accumulation mode. 

Features of the general-purpose timer include:

• Four 16-bit input capture/output compare channels
• 16-bit architecture
• Programmable prescaler
• Pulse widths variable from microseconds to seconds
• Single 16-bit pulse accumulator
• Toggle-on-overflow feature for pulse-width modulator (PWM) generation
• External timer clock input (SYNCA/SYNCB)