MC9S12P128 Datasheet, PDF (106/564 Pages) Freescale Semiconductor, Inc – S12 Microcontrollers

Port Integration Module (S12PPIMV1)
t_pulse
Figure 2-66. Pulse Illustration
A valid edge on an input is detected if 4 consecutive samples of a passive level are followed by 4
consecutive samples of an active level directly or indirectly.
The filters are continuously clocked by the bus clock in RUN and WAIT mode. In STOP mode the clock
is generated by an RC-oscillator in the Port Integration Module. To maximize current saving the RC
oscillator runs only if the following condition is true on any pin individually:
Sample count <= 4 and interrupt enabled (PIE=1) and interrupt flag not set (PIF=0).
2.5 Initialization Information
2.5.1 Port Data and Data Direction Register writes
It is not recommended to write PORTx/PTx and DDRx in a word access. When changing the register pins
from inputs to outputs, the data may have extra transitions during the write access. Initialize the port data
register before enabling the outputs.
S12P-Family Reference Manual, Rev. 1.12
106
Freescale Semiconductor