MC68HC812A4 Datasheet, PDF (203/342 Pages) Motorola, Inc – 16-bit device composed of standard on-chip peripheral modules connected by an intermodule bus. Modules include

Standard Timer Module
External Pins
12.7 External Pins
The timer has eight pins for input capture and output compare functions.
One of the pins is also the pulse accumulator input. All eight pins are
available for general-purpose I/O when not configured for timer
functions.
12.7.1 Input Capture/Output Compare Pins
The IOSx bits in the timer IC/OC select register configure the timer port
pins as either output compare or input capture pins.
The timer port data direction register controls the data direction of an
input capture pin. External pin conditions trigger input captures on input
capture pins configured as inputs. Software triggers input captures on
input capture pins configured as outputs.
The timer port data direction register does not affect the data direction of
an output compare pin. The output compare function overrides the data
direction register but does not affect the state of the data direction
register.
12.7.2 Pulse Accumulator Pin
Setting the PAE bit in the pulse accumulator control register enables the
pulse accumulator input pin, PAI.
NOTE:
The PAI input and timer channel 7 use the same pin. To use the PAI
input, disconnect it from the output logic by clearing the channel 7 output
mode and output level bits, OM7 and OL7. Also clear the channel 7
output compare mask bit, OC7M7.
Advance Information
MOTOROLA
Standard Timer Module
MC68HC812A4 — Rev. 3.0
203