Datasheet

Chapter 3 Port Integration Module (PIM9E128V1)
MC9S12E128 Data Sheet, Rev. 1.07
Freescale Semiconductor 151
3.3.5.6 Port S Polarity Select Register (PPSS)
Read: Anytime. Write: Anytime.
The Port S Polarity Select Register selects whether a pull-down or a pull-up device is connected to the pin.
The Port S Polarity Select Register is effective only when the corresponding Data Direction Register bit
is set to 0 (input) and the corresponding Pull Device Enable Register bit is set to 1.
3.3.5.7 Port S Wired-OR Mode Register (WOMS)
Read: Anytime. Write: Anytime.
This register selects whether a port S output is configured as push-pull or wired-or. When a Wired-OR
Mode Register bit is set to 1, the corresponding output pin is driven active low only (open drain) and a
high level is not driven. A Wired-OR Mode Register bit has no effect if the corresponding pin is configured
as an input.
76543210
R
PPSS7 PPSS6 PPSS5 PPSS4 PPSS3 PPSS2 PPSS1 PPSS0
W
Reset 0 0 0 00000
Figure 3-34. Port S Polarity Select Register (PPSS)
Table 3-25. PPSS Field Descriptions
Field Description
7:0
PPSS[7:0]
Pull Select Port S
0 A pull-up device is connected to the associated port S pin.
1 A pull-down device is connected to the associated port S pin.
76543210
R
WOMS7 WOMS6 WOMS5 WOMS4 WOMS3 WOMS2 WOMS1 WOMS0
W
Reset 0 0 0 00000
Figure 3-35. Port S Wired-OR Mode Register (WOMS)
Table 3-26. WOMS Field Descriptions
Field Description
7:0
WOMS[7:0]
Wired-OR Mode Port S
0 Output buffers operate as push-pull outputs.
1 Output buffers operate as open-drain outputs.