mc9s12xd256 Freescale Semiconductor, Inc, mc9s12xd256 Datasheet - Page 969

• Manufacturer Part Number: mc9s12xd256
• Description: Hcs12x Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

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).
23.0.9
All peripheral ports T, S, M, P, H, J, AD0, and AD1 start up as general purpose inputs after reset.
Depending on the external mode pin condition, the external bus interface related ports A, B, C, D,
E, and K start up as general purpose inputs on reset or are configured for their alternate functions.
Glitch, filtered out, no interrupt flag set
Valid pulse, interrupt flag set
Expanded Bus Pin Functions
Figure 23-77. Interrupt Glitch Filter on Port P, H, and J (PPS = 0)
Uncertain
1. These values include the spread of the oscillator frequency over
Ignored
Pulse
Valid
temperature, voltage and process.
Table 23-69. Pulse Detection Criteria
t
pign
Figure 23-78. Pulse Illustration
3 < t
t
pval
t
t
pulse
pulse
STOP
pulse
< 4
3
4
uncertain
t
pulse
Bus clocks
Bus clocks
Bus clocks
Unit
Mode
t
pign
t
t
pulse
pulse
< t
STOP
pulse
t
t
pign
1
pval
< t
pval