S912XHZ512F1VAG Datasheet, PDF (77/978 Pages) Freescale Semiconductor, Inc – Covers MC9S12XHZ384, MC9S12XHZ256

2.3.5 Miscellaneous registers
Chapter 2 Port Integration Module (S12XHZPIMV1)
2.3.5.1 Pull Up/Down Control Register (PUCR)
Module Base + 0x0055
R
W
Reset
7
PUPKE
1
6
5
4
3
2
0
BKGPE
PUPEE
PUPDE
PUPCE
1
0
1
0
0
Figure 2-14. Pull Up/Down Control Register (PUCR)
1
PUPBE
1
0
PUPAE
1
Read: Anytime. Write: Anytime except BKPUE which is writable in special test mode only.
This register is used to enable pull up/down devices for the associated ports A, B, C, D, E and K. Pull
up/down devices are assigned on a per-port basis and apply to any pin in the corresponding port currently
configured as an input.
Table 2-9. PUCR Field Descriptions
Field
7
PUPKE
6
BKPUE
4
PUPEE
3
PUPDE
2
PUPCE
1
PUPBE
0
PUPAE
Description
Pull-down Port K Enable
0 Port K pull-down devices are disabled.
1 Enable pull-down devices for Port K input pins.
BKGD Pin Pull-up Enable
0 BKGD pull-up device is disabled.
1 Enable pull-up device on BKGD pin.
Pull Port E Enable
0 Port E pull-down devices on pins 7, 4–2 are disabled. Port E pull-up devices on pins 1–0 are disabled.
1 Enable pull-down devices for Port E input pins 7, 4–2. Enable pull-up devices for Port E input pins 1–0.
Note: Bits 5 and 6 of Port E have pull-down devices which are only enabled during reset. This bit has no effect
on these pins.
Pull-up Port D Enable
0 Port D pull-up devices are disabled.
1 Enable pull-up devices for all Port D input pins.
Pull-up Port C Enable
0 Port C pull-up devices are disabled.
1 Enable pull-up devices for all Port C.
Pull-down Port B Enable
0 Port B pull-down devices are disabled.
1 Enable pull-down devices for all Port B input pins.
Pull-down Port A Enable
0 Port A pull-down devices are disabled.
1 Enable pull-down devices for all Port A input pins.
MC9S12XHZ512 Data Sheet, Rev. 1.06
Freescale Semiconductor
77