Datasheet

Chapter 22 DP512 Port Integration Module (S12XDP512PIMV2)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor 853
22.3.2.35 Port M Polarity Select Register (PPSM)
Read: Anytime.
Write: Anytime.
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.
22.3.2.36 Port M Wired-OR Mode Register (WOMM)
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 CAN outputs and allows a multipoint
connection of several serial modules. This bit has no influence on pins used as inputs.
76543210
R
PPSM7 PPSM6 PPSM5 PPSM4 PPSM3 PPSM2 PPSM1 PPSM0
W
Reset 00000000
Figure 22-37. Port M Polarity Select Register (PPSM)
Table 22-36. PPSM Field Descriptions
Field Description
7–0
PPSM[7:0]
Pull Select Port M
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.
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.
76543210
R
WOMM7 WOMM6 WOMM5 WOMM4 WOMM3 WOMM2 WOMM1 WOMM0
W
Reset 00000000
Figure 22-38. Port M Wired-OR Mode Register (WOMM)
Table 22-37. WOMM Field Descriptions
Field Description
7–0
WOMM[7:0]
Wired-OR Mode Port M
0 Output buffers operate as push-pull outputs.
1 Output buffers operate as open-drain outputs.