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Chapter 4 Port Integration Module (S12XDP512PIMV2)
MC9S12XDP512 Data Sheet, Rev. 2.11
Freescale Semiconductor 221
4.3.2.28 Port S Polarity Select Register (PPSS)
Read: Anytime.
Write: Anytime.
This register selects whether a pull-down or a pull-up device is connected to the pin.
4.3.2.29 Port S Wired-OR Mode Register (WOMS)
Read: Anytime.
Write: Anytime.
This register configures the output pins as wired-OR. If enabled the output is driven active low only
(open-drain). A logic level of “1” is not driven. It applies also to the SPI and SCI outputs and allows a
multipoint connection of several serial modules. These bits have no influence on pins used as inputs.
0x024D
76543210
R
PPSS7 PPSS6 PPSS5 PPSS4 PPSS3 PPSS2 PPSS1 PPSS0
W
Reset 00000000
Figure 4-30. Port S Polarity Select Register (PPSS)
Table 4-30. 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, if enabled by the associated bit in register PERS
and if the port is used as input or as wired-OR output.
1 A pull-down device is connected to the associated port S pin, if enabled by the associated bit in register PERS
and if the port is used as input.
0x024E
76543210
R
WOMS7 WOMS6 WOMS5 WOMS4 WOMS3 WOMS2 WOMS1 WOMS0
W
Reset 00000000
Figure 4-31. Port S Wired-OR Mode Register (WOMS)
Table 4-31. 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.