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Chapter 2 Port Integration Module (S12XEPIMV1)
MC9S12XE-Family Reference Manual Rev. 1.07
Freescale Semiconductor
129
2.3.42
Port M Polarity Select Register (PPSM)
2.3.43
Port M Wired-Or Mode Register (WOMM)
Address 0x0255
Access: User read/write
1
1
Read: Anytime.
Write: Anytime.
7
6
5
4
3
2
1
0
R
PPSM7
PPSM6
PPSM5
PPSM4
PPSM3
PPSM2
PPSM1
PPSM0
W
Reset
0
0
0
0
0
0
0
0
Figure 2-40. Port M Polarity Select Register (PPSM)
Table 2-37. PPSM Register Field Descriptions
Field
Description
7-0
PPSM
Port M pull device select
—Determine pull device polarity on input pins
This register selects whether a pull-down or a pull-up device is connected to the pin. If CAN is active a pull-up device
can be activated on the RXCAN[3:0] inputs, but not a pull-down.
1 A pull-down device is connected to the associated Port M pin, if enabled by the associated bit in register PERM
and if the port is used as a general purpose but not as RXCAN.
0 A pull-up device is connected to the associated Port M pin, if enabled by the associated bit in register PERM and
if the port is used as general purpose or RXCAN input.
Address 0x0256
Access: User read/write
1
1
Read: Anytime.
Write: Anytime.
7
6
5
4
3
2
1
0
R
WOMM7
WOMM6
WOMM5
WOMM4
WOMM3
WOMM2
WOMM1
WOMM0
W
Reset
0
0
0
0
0
0
0
0
Figure 2-41. Port M Wired-Or Mode Register (WOMM)
Table 2-38. WOMM Register Field Descriptions
Field
Description
7-0
WOMM
Port M wired-or mode
—Enable wired-or functionality
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.This allows a multipoint connection of several serial modules. These bits have no
influence on pins used as inputs.
1 Output buffers operate as open-drain outputs.
0 Output buffers operate as push-pull outputs.