Freescale Semiconductor, Inc.
Technical Data — MC68HC705C8A
Section 8. Capture/Compare Timer
8.1 Contents
8.2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
8.3
8.3.1
8.3.2
Timer Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
Input Capture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92
Output Compare. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93
8.4
Timer I/O Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94
Timer Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94
Timer Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96
Timer Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97
Alternate Timer Registers. . . . . . . . . . . . . . . . . . . . . . . . . . .98
Input Capture Registers . . . . . . . . . . . . . . . . . . . . . . . . . .100
Output Compare Registers. . . . . . . . . . . . . . . . . . . . . . . . .101
8.4.1
8.4.2
8.4.3
8.4.4
8.4.5
8.4.6
8.2 Introduction
This section describes the operation of the 16-bit capture/compare timer.
Figure 8-1 shows the structure of the timer module. Figure 8-2 is a
summary of the timer input/output (I/O) registers.
8.3 Timer Operation
The core of the capture/compare timer is a 16-bit free-running counter.
The counter is the timing reference for the input capture and output
compare functions. The input capture and output compare functions can
latch the times at which external events occur, measure input
waveforms, and generate output waveforms and timing delays. Software
can read the value in the counter at any time without affecting the
counter sequence.
MC68HC705C8A — Rev. 3
MOTOROLA
Technical Data
Capture/Compare Timer
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