MC68HC08AS20 Datasheet, PDF (215/386 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

16.8 I/O Signals
Port D shares one of its pins with the TIM. Port E shares two of its pins
with the TIM and port F shares four of its pins with the TIM.
PTD6/ATD14/TCLK is an external clock input to the TIM prescaler. The
six TIM channel I/O pins are PTE2/TCH0, PTE3/TCH1, PTF0/TCH2,
PTF1/TCH3, PTF2/TCH4, and PTF3/TCH5.
16.8.1 TIM Clock Pin (PTD6/ATD14/TCLK)
PTD6/ATD14/TCLK is an external clock input that can be the clock
source for the TIM counter instead of the prescaled internal bus clock.
Select the PTD6/ATD14/TCLK input by writing logic 1s to the three
prescaler select bits, PS[2–0]. (See 16.9.1 TIM Status and Control
Register.) The minimum TCLK pulse width, TCLK_LMIN or TCLK_HMIN, is:
------------------1-------------------
bus frequency
+
t_SU
The maximum TCLK frequency is the least: 4 MHz or bus frequency ÷ 2.
PTD6/ATD14/TCLK is available as a general-purpose I/O pin or ADC
channel when not used as the TIM clock input. When the
PTD6/ATD14/TCLK pin is the TIM clock input, it is an input regardless of
the state of the DDRD6 bit in data direction register D.
16.8.2 TIM Channel I/O Pins (PTF3/TCH5–PTF0/TCH2 and PTE3/TCH1–PTE2/TCH0)
Each channel I/O pin is programmable independently as an input
capture pin or an output compare pin. PTE2/TCH0, PTE6/TCH2, and
PTF2/TCH4 can be configured as buffered output compare or buffered
PWM pins.
MC68HC08AS20 — Rev. 4.1
Freescale Semiconductor
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