MC9S08QG8_09 Datasheet, PDF (33/314 Pages) Freescale Semiconductor, Inc – HCS08 Microcontrollers

Chapter 2 External Signal Description
NOTE
When an alternative function is first enabled, it is possible to get a spurious
edge to the module. User software should clear out any associated flags
before interrupts are enabled. Table 2-1 shows the priority if multiple
modules are enabled. The highest priority module will have control over the
pin. Selecting a higher priority pin function with a lower priority function
already enabled can cause spurious edges to the lower priority module. It is
recommended that all modules that share a pin be disabled before enabling
anther module.
MC9S08QG8 and MC9S08QG4 Data Sheet, Rev. 5
Freescale Semiconductor
31