MC908AB32CFUE Datasheet, PDF (171/392 Pages) Freescale Semiconductor, Inc – Microcontrollers

Timer Interface Module A (TIMA)
11.4 Pin Name Conventions
The TIMA share five I/O pins with port D, E, and F I/O pins. The full name
of the TIMA I/O pin is listed in Table 11-1. The generic pin name appear
in the text that follows.
Table 11-1. Pin Name Conventions
TIMA Generic Pin Names:
TACLK
TACH0
TACH1
TACH2
TACH3
Full TIMA Pin Names:
PTD6/TACLK
PTE2/TACH0
PTE3/TACH1
PTF0/TACH2
PTF1/TACH3
11.5 Functional Description
Figure 11-1 shows the structure of the TIMA. The central component of
the TIMA is the 16-bit TIMA counter that can operate as a free-running
counter or a modulo up-counter. The TIMA counter provides the timing
reference for the input capture and output compare functions. The TIMA
counter modulo registers, TAMODH:TAMODL, control the modulo value
of the TIMA counter. Software can read the TIMA counter value at any
time without affecting the counting sequence.
The four TIMA channels are programmable independently as input
capture or output compare channels.
11.5.1 TIMA Counter Prescaler
The TIMA clock source can be one of the seven prescaler outputs or the
TIMA clock pin, PTD6/TACLK. The prescaler generates seven clock
rates from the internal bus clock. The prescaler select bits, PS[2:0], in
the TIMA status and control register select the TIMA clock source.
MC68HC908AB32 — Rev. 1.1
Freescale Semiconductor
Timer Interface Module A (TIMA)
Technical Data
171