MC68HC08AZ32A Datasheet, PDF (246/312 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Timer Interface Module A (TIMA)
17.7 I/O Signals
Port D shares one of its pins with the TIMA. Port E shares two of its pins with the TIMA and port F shares
four of its pins with the TIMA. PTD6/ATD14/TACLK is an external clock input to the TIMA prescaler. The
six TIMA channel I/O pins are PTE2/TACH0, PTE3/TACH1, PTF0/TACH2, PTF1/TACH3, PTF2, and
PTF3.
17.7.1 TIMA Clock Pin (PTD6/ATD14/TACLK)
PTD6/ATD14/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/ATD14/TACLK input by writing 1s to the three
prescaler select bits, PS[2:0] (see 17.8.1 TIMA 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/TACLK is available as a general-purpose I/O pin or ADC channel when not used as the
TIMA clock input. When the PTD6/ATD14/TACLK pin is the TIMA clock input, it is an input regardless of
the state of the DDRD6 bit in data direction register D.
17.7.2 TIMA Channel I/O Pins (PTF3–PTF0/TACH2 and PTE3/TACH1–PTE2/TACH0)
Each channel I/O pin is programmable independently as an input capture pin or an output compare pin.
PTE2/TACH0, PTF0/TACH2 and PTF2 can be configured as buffered output compare or buffered PWM
pins.
17.8 I/O Registers
These I/O registers control and monitor TIMA operation:
• TIMA status and control register (TASC)
• TIMA control registers (TACNTH–TACNTL)
• TIMA counter modulo registers (TAMODH–TAMODL)
• TIMA channel status and control registers (TASC0–TASC5)
• TIMA channel registers (TACH0H–TACH0L through TACH5H–TACH5L)
17.8.1 TIMA Status and Control Register
The TIMA status and control register:
• Enables TIMA overflow interrupts
• Flags TIMA overflows
• Stops the TIMA counter
• Resets the TIMA counter
• Prescales the TIMA counter clock
MC68HC08AZ32A Data Sheet, Rev. 2
246
Freescale Semiconductor