Port Integration Module (S12PPIMV1)
PTI
0
1
PIN
0
1
PT
0
1
DDR
data out
Module
output enable
module enable
Figure 2-64. Illustration of I/O pin functionality
2.4.2.4
Reduced drive register (RDRx)
If the pin is used as an output this register allows the configuration of the drive strength independent of the
use with a peripheral module.
2.4.2.5
Pull device enable register (PERx)
This register turns on a pull-up or pull-down device on the related pins determined by the associated
polarity select register (2.4.2.6/2-102).
The pull device becomes active only if the pin is used as an input or as a wired-or output. Some peripheral
module only allow certain configurations of pull devices to become active. Refer to the respective bit
descriptions.
2.4.2.6
Polarity select register (PPSx)
This register selects either a pull-up or pull-down device if enabled.
It becomes only active if the pin is used as an input. A pull-up device can be activated if the pin is used as
a wired-or output.
2.4.2.7
Wired-or mode register (WOMx)
If the pin is used as an output this register turns off the active high drive. This allows wired-or type
connections of outputs.
S12P-Family Reference Manual, Rev. 1.13
102
Freescale Semiconductor
FREESCALE [ Freescale ]
