S912XHZ512F1VAG Datasheet, PDF (94/978 Pages) Freescale Semiconductor, Inc – Covers MC9S12XHZ384, MC9S12XHZ256

Chapter 2 Port Integration Module (S12XHZPIMV1)
The Port M Polarity Select Register selects whether a pull-down or a pull-up device is connected to the
pin. The Port M 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.
If a CAN module is enabled, a pull-up device can be activated on the receiver pin, and on the transmitter
pin if the corresponding wired-OR mode bit is set. Pull-down devices can not be activated on CAN pins.
Table 2-29. PPSM Field Descriptions
Field
Description
5:1
Pull Select Port M
PPSM[5:1] 0 A pull-up device is connected to the associated port M pin.
1 A pull-down device is connected to the associated port M pin.
2.3.8.7 Port M Wired-OR Mode Register (WOMM)
Module Base + 0x0016
7
R
0
W
6
5
4
3
2
1
0
0
0
WOMM5 WOMM4 WOMM3 WOMM2 WOMM1
Reset
0
0
0
0
0
0
0
0
= Reserved or Unimplemented
Figure 2-40. Port M Wired-OR Mode Register (WOMM)
Read: Anytime. Write: Anytime.
This register selects whether a port M 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.
These bits apply also to the CAN transmitter and allow a multipoint connection of several serial modules.
Table 2-30. WOMM Field Descriptions
Field
Description
5:1
Wired-OR Mode Port M
WOMM[5:1] 0 Output buffers operate as push-pull outputs.
1 Output buffers operate as open-drain outputs.
MC9S12XHZ512 Data Sheet, Rev. 1.06
94
Freescale Semiconductor