Chapter 2 Port Integration Module (PIM9C32) Block Description
106
MC9S12C-Family / MC9S12GC-Family
Freescale Semiconductor
Rev 01.24
2.4.2.5
Port P
The PWM module is connected to port P. Port P pins can be used as PWM outputs. Further the Keypad
Wake-Up function is implemented on pins PP[7:0]. During reset, port P pins are configured as high-
impedance inputs.
Port P offers 8 general purpose I/O pins with edge triggered interrupt capability in wired-or fashion. The
interrupt enable as well as the sensitivity to rising or falling edges can be individually configured on per
pin basis. All 8 bits/pins share the same interrupt vector. Interrupts can be used with the pins configured
as inputs or outputs.
An interrupt is generated when a bit in the port interrupt flag register and its corresponding port interrupt
enable bit are both set. This external interrupt feature is capable to wake up the CPU when it is in STOP
or WAIT mode.
A digital filter on each pin prevents pulses (
) shorter than a specified time from generating an
interrupt. The minimum time varies over process conditions, temperature and voltage (
).
Figure 2-47. Interrupt Glitch Filter on Port P and J (PPS = 0)
Figure 2-48. Pulse Illustration
Table 2-38. Pulse Detection Criteria
Pulse
STOP Mode
STOP
(1)
Mode
1. These values include the spread of the oscillator frequency over temperature,
voltage and process.
Value
Unit
Value
Unit
Ignored
t
pign
<= 3
Bus clocks
t
pign
<= 3.2
µ
s
Uncertain
3 < t
pulse
< 4
Bus clocks
3.2 < t
pulse
< 10
µ
s
Valid
t
pval
>= 4
Bus clocks
t
pval
>= 10
µ
s
Glitch, filtered out, no interrupt flag set
Valid pulse, interrupt flag set
t
pign
t
pval
t
pulse
Summary of Contents for MC9S12C Family
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