MC9S12E128 Datasheet, PDF (150/606 Pages) Freescale Semiconductor, Inc – HCS12 Microcontrollers

Chapter 3 Port Integration Module (PIM9E128V1)
3.3.5.4 Port S Reduced Drive Register (RDRS)
R
W
Reset
7
RDRS7
0
6
RDRS6
5
RDRS5
4
RDRS4
3
RDRS3
2
RDRS2
0
0
0
0
0
Figure 3-32. Port S Reduced Drive Register (RDRS)
1
RDRS1
0
0
RDRS0
0
Read: Anytime. Write: Anytime.
This register configures the drive strength of configured output pins as either full or reduced. If a pin is
configured as input, the corresponding Reduced Drive Register bit has no effect.
Table 3-23. RDRS Field Descriptions
Field
Description
7:0
Reduced Drive Port S
RDRS[7:0] 0 Full drive strength at output.
1 Associated pin drives at about 1/3 of the full drive strength.
3.3.5.5 Port S Pull Device Enable Register (PERS)
7
R
PERS7
W
6
PERS6
5
PERS5
4
PERS4
3
PERS3
2
PERS2
1
PERS1
0
PERS0
Reset
1
1
1
1
1
1
1
1
= Reserved or Unimplemented
Figure 3-33. Port S Pull Device Enable Register (PERS)
Read: Anytime. Write: Anytime.
This register configures whether a pull-up or a pull-down device is activated on configured input or
wired-or (open drain) output pins. If a pin is configured as push-pull output, the corresponding Pull Device
Enable Register bit has no effect.
Table 3-24. PERS Field Descriptions
Field
7:0
Pull Device Enable Port S
PERS[7:0] 0 Pull-up or pull-down device is disabled.
1 Pull-up or pull-down device is enabled.
Description
MC9S12E128 Data Sheet, Rev. 1.07
150
Freescale Semiconductor