mc68hc908qb4 Freescale Semiconductor, Inc, mc68hc908qb4 Datasheet - Page 175

• Manufacturer Part Number: mc68hc908qb4
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 16
Timer Interface Module (TIM)
16.1 Introduction
This section describes the timer interface module (TIM). The TIM module is a 4-channel timer that
provides a timing reference with input capture, output compare, and pulse-width-modulation functions.
The TIM module shares its pins with general-purpose input/output (I/O) port pins. See
location of these shared pins.
16.2 Features
Features include the following:
16.3 Functional Description
Figure 16-2
can operate as a free-running counter or a modulo up-counter. The counter provides the timing reference
for the input capture and output compare functions. The TIM counter modulo registers, TMODH:TMODL,
control the modulo value of the counter. Software can read the counter value, TCNTH:TCNTL, at any time
without affecting the counting sequence.
The four TIM channels are programmable independently as input capture or output compare channels.
16.3.1 TIM Counter Prescaler
The TIM clock source is one of the seven prescaler outputs or the external clock input pin, TCLK if
available. The prescaler generates seven clock rates from the internal bus clock. The prescaler select
bits, PS[2:0], in the TIM status and control register (TSC) select the clock source.
Freescale Semiconductor
•
•
•
•
•
•
Four input capture/output compare channels
–
–
Buffered and unbuffered output compare pulse-width modulation (PWM) signal generation
Programmable clock input
–
–
Free-running or modulo up-count operation
Toggle any channel pin on overflow
Counter stop and reset bits
Rising-edge, falling-edge, or any-edge input capture trigger
Set, clear, or toggle output compare action
7-frequency internal bus clock prescaler selection
External clock input pin if available, See
shows the structure of the TIM. The central component of the TIM is the 16-bit counter that
MC68HC908QB8 Data Sheet, Rev. 2
Figure 16-1
Figure 16-1
for port
175