Datasheet

Chapter 3 Port Integration Module (PIM9E128V1)
MC9S12E128 Data Sheet, Rev. 1.07
134 Freescale Semiconductor
3.3.1.6 Port AD Polarity Select Register (PPSAD)
Read: Anytime. Write: Anytime.
The Port AD Polarity Select Register serves a dual purpose by selecting the polarity of the active interrupt
edge as well as selecting a pull-up or pull-down device if enabled (PERADx = 1). The Port AD Polarity
Select Register is effective only when the corresponding Data Direction Register bit is set to 0 (input).
In pull-down mode (PPSADx = 1), a rising edge on a port AD pin sets the corresponding PIFADx bit. In
pull-up mode (PPSADx = 0), a falling edge on a port AD pin sets the corresponding PIFADx bit.
76543210
R
PPSAD15 PPSAD14 PPSAD13 PPSAD12 PPSAD11 PPSAD10 PPSAD9 PPSAD8
W
Reset 0 0 0 00000
76543210
R
PPSAD7 PPSAD6 PPSAD5 PPSAD4 PPSAD3 PPSAD2 PPSAD1 PPSAD0
W
Reset 0 0 0 00000
Figure 3-7. Port AD Polarity Select Register (PPSAD)
Table 3-6. PPSAD Field Descriptions
Field Description
15:0
PPSAD[15:0]
Polarity Select Port AD
0 A pull-up device is connected to the associated port AD pin, and detects falling edge for interrupt generation.
1 A pull-down device is connected to the associated port AD pin, and detects rising edge for interrupt
generation.