MC68HC912BD32 Datasheet, PDF (66/292 Pages) Freescale Semiconductor, Inc – Advance Information

Freescale Semiconductor, Inc.
Bus Control and Input/Output
R/W is used for external writes. After reset in normal expanded mode,
it is disabled. If needed it should be enabled before any external
writes.
PUCR — Pull Up Control Register
Bit 7
6
5
4
3
0
0
0
PUPE
0
RESET:
0
0
0
1
0
$000C
2
1
Bit 0
0
PUPB
PUPA
0
0
0
These bits select pull-up resistors for any pin in the corresponding port
that is currently configured as an input. This register is not in the map in
peripheral mode.
Read and write anytime.
PUPE — Pull-Up Port E Enable
Pin PE1 always has a pull-up. Pins PE6, PE5, and PE4 never have
pull-ups.
0 = Port E pull-ups on PE7, PE3, PE2, and PE0 are disabled.
1 = Enable pull-up devices for port E input pins PE7, PE3, PE2, and
PE0.
PUPB — Pull-Up Port B Enable
0 = Port B pull-ups are disabled.
1 = Enable pull-up devices for all port B input pins.
This bit has no effect if port B is being used as part of the address/data
bus (the pull-ups are inactive).
PUPA — Pull-Up Port A Enable
0 = Port A pull-ups are disabled.
1 = Enable pull-up devices for all port A input pins.
This bit has no effect if port A is being used as part of the address/data
bus (the pull-ups are inactive).
MC68HC912BD32 Rev 1.0
Bus Control and Input/Output
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8-bus