Freescale Semiconductor Demonstration Board for Freescale MC9S12XHY256 Microcontroller DEMO9S12XHY256 DEMO9S12XHY256 用户手册
产品代码
DEMO9S12XHY256
Port Integration Module (S12XHYPIMV1)
MC9S12XHY-Family Reference Manual, Rev. 1.04
152
Freescale Semiconductor
Figure 2-94. Illustration of I/O pin functionality
2.4.2.4
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 (
polarity select register (
).
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.
module only allow certain configurations of pull devices to become active. Refer to the respective bit
descriptions.
2.4.2.5
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.
a wired-or output.
2.4.2.6
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.
connections of outputs.
2.4.2.7
Interrupt enable register (PIEx)
If the pin is used as an interrupt input this register serves as a mask to the interrupt flag to enable/disable
the interrupt.
the interrupt.
2.4.2.8
Interrupt flag register (PIFx)
If the pin is used as an interrupt input this register holds the interrupt flag after a valid pin event.
PT
DDR
output enable
module enable
1
0
1
1
0
0
PIN
PTI
data out
Module