Freescale Semiconductor ColdFire MCF52210 - Manual (Page 28)

Overview
MCF52211 ColdFire® Integrated Microcontroller Reference Manual, Rev. 2
1-12 Freescale Semiconductor
register (TCRn). Each of these timers can be configured for input capture or reference (output) compare
mode. Timer events may optionally cause interrupt requests or DMA transfers.
1.2.12 General Purpose Timer (GPT)
The general purpose timer (GPT) is a four-channel timer module consisting of a 16-bit programmable
counter driven by a seven-stage programmable prescaler. Each of the four channels can be configured for
input capture or output compare. Additionally, channel three, can be configured as a pulse accumulator.
A timer overflow function allows software to extend the timing capability of the system beyond the 16-bit
range of the counter. The input capture and output compare functions allow simultaneous input waveform
measurements and output waveform generation. The input capture function can capture the time of a
selected transition edge. The output compare function can generate output waveforms and timer software
delays. The 16-bit pulse accumulator can operate as a simple event counter or a gated time accumulator.
1.2.13 Periodic Interrupt Timers (PIT0 and PIT1)
The two periodic interrupt timers (PIT0 and PIT1) are 16-bit timers that provide interrupts at regular
intervals with minimal processor intervention. Each timer can count down from the value written in its PIT
modulus register or it can be a free-running down-counter.
1.2.14 Real-Time Clock (RTC)
The Real-Time Clock (RTC) module maintains the system (time-of-day) clock and provides stopwatch,
alarm, and interrupt functions. It includes full clock features: seconds, minutes, hours, days and supports
a host of time-of-day interrupt functions along with an alarm interrupt.
1.2.15 Pulse-Width Modulation (PWM) Timers
The MCF52211 has an 8-channel, 8-bit PWM timer. Each channel has a programmable period and duty
cycle as well as a dedicated counter. Each of the modulators can create independent continuous waveforms
with software-selectable duty rates from 0% to 100%. The timer supports PCM mode, which results in
superior signal quality when compared to that of a conventional PWM. The PWM outputs have
programmable polarity, and can be programmed as left aligned outputs or center aligned outputs. For
higher period and duty cycle resolution, each pair of adjacent channels ([7:6], [5:4], [3:2], and [1:0]) can
be concatenated to form a single 16-bit channel. The module can, therefore, be configured to support 8/0,
6/1, 4/2, 2/3, or 0/4 8-/16-bit channels.
1.2.16 Software Watchdog Timer
The watchdog timer is a 32-bit timer that facilitates recovery from runaway code. The watchdog counter
is a free-running down-counter that generates a reset on underflow. To prevent a reset, software must
periodically restart the countdown.