MC3S12RG128 Datasheet, PDF (277/546 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 10
Enhanced Capture Timer (ECT16B8CV1) Block Description
10.1 Introduction
The HCS12 Enhanced Capture Timer module has the features of the HCS12 Standard Timer module
enhanced by additional features in order to enlarge the field of applications, in particular for automotive
ABS applications.
This design specification describes the standard timer as well as the additional features.
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.
10.1.1 Features
• 16-bit Buffer Register for four Input Capture (IC) channels.
• Four 8-bit Pulse Accumulators with 8-bit buffer registers associated with the four buffered IC
channels. Configurable also as two 16-bit Pulse Accumulators.
• 16-bit Modulus Down-Counter with 4-bit Prescaler.
• Four user selectable Delay Counters for input noise immunity increase.
10.1.2 Modes of Operation
STOP:
Timer and modulus counter are off since clocks are stopped.
FREEZE: Timer and modulus counter keep on running, unless TSFRZ in TSCR (0x0006) is set to one.
WAIT:
Counters keep on running, unless TSWAI in TSCR (0x0006) is set to one.
NORMAL: Timer and modulus counter keep on running, unless TEN in TSCR (0x0006) respectively
MCEN in MCCTL (0x0026) are cleared.
MC3S12RG128 Data Sheet, Rev. 1.05
Freescale Semiconductor
277