XC912BC32CFU8 Motorola Semiconductor Products, XC912BC32CFU8 Datasheet - Page 169

• Manufacturer Part Number: XC912BC32CFU8
• Description: M68HC12B Family Data Sheet
• Manufacturer: Motorola Semiconductor Products

13.1 Introduction
13.2 Basic Timer Overview
13.3 Enhanced Capture Timer Modes of Operation
M68HC12B Family — Rev. 8.0
MOTOROLA
Data Sheet — M68HC12B Family
The M68HC12 enhanced capture timer (ECT) module has the features of the
M68HC12 standard timer (TIM) module enhanced by additional features in order
to enlarge the field of applications.
These additional features are:
This section describes the standard timer found on the MC68HC912B32 as well as
the additional features found on the MC68HC12BE32.
The basic timer consists of a 16-bit, software-programmable counter driven by a
prescaler. This timer can be used for many purposes, including input waveform
measurements while simultaneously generating an output waveform. Pulse widths
can vary from microseconds to many seconds.
A full access for the counter registers or the input capture/output compare registers
should take place in one clock cycle. Accessing high byte and low byte separately
for all of these registers may not yield the same result as accessing them in one
word.
The enhanced capture timer has eight input capture, output compare (IC/OC)
channels same as on the M68HC12 standard timer (timer channels TC0–TC7).
When channels are selected as input capture by selecting the IOSx bit in the timer
input capture/output compare select register (TIOS), they are called input capture
(IC) channels.
•
•
•
•
•
16-bit buffer register for four input capture (IC) channels
Four 8-bit pulse accumulators:
–
–
16-bit modulus down-counter with 4-bit prescaler
Four user selectable delay counters for input noise immunity increase
Main timer prescaler extended to 7-bit
8-bit buffer registers associated with the four buffered IC channels
Configurable as two 16-bit pulse accumulators
Section 13. Enhanced Capture Timer (ECT) Module
Enhanced Capture Timer (ECT) Module
Data Sheet
169