MC908AB32CFUE Datasheet, PDF (183/392 Pages) Freescale Semiconductor, Inc – Microcontrollers

Timer Interface Module A (TIMA)
11.9 I/O Signals
Ports E and F each share two pins with the TIMA and port D shares one.
PTD6/TACLK is an external clock input to the TIMA prescaler. The four
TIMA channel I/O pins are PTE2/TACH0, PTE3/TACH1, PTF0/TACH2,
and PTF1/TACH3.
11.9.1 TIMA Clock Pin
PTD6/TACLK is an external clock input that can be the clock source for
the TIMA counter instead of the prescaled internal bus clock. Select the
PTD6/TACLK input by writing logic 1s to the three prescaler select bits,
PS[2:0]. See 11.10.1 TIMA Status and Control Register. The minimum
TACLK pulse width, TACLK_LMIN or TACLK_HMIN, is:
------------------1-------------------
bus frequency
+
t_SU
The maximum TACLK frequency is:
bus frequency ÷ 2
PTD6/TACLK is available as a general-purpose I/O pin when not used
as the TIMA clock input. When the PTD6/TACLK pin is the TIMA clock
input, it is an input regardless of the state of the DDRD6 bit in data
direction register D.
11.9.2 TIMA Channel I/O Pins
Each channel I/O pin is programmable independently as an input
capture pin or an output compare pin. PTF0/TACH2 and PTE3/TACH1
can be configured as buffered output compare or buffered PWM pins.
MC68HC908AB32 — Rev. 1.1
Freescale Semiconductor
Timer Interface Module A (TIMA)
Technical Data
183