MC68HC912B32 Datasheet, PDF (19/128 Pages) Motorola, Inc – 16-Bit Microcontroller

3.5 Port Pull-Up, Pull-Down and Reduced Drive
MCU ports can be configured for internal pull-up. To reduce power consumption and RFI, the pin output
drivers can be configured to operate at a reduced drive level. Reduced drive causes a slight increase
in transition time depending on loading and should be used only for ports which have a light loading.
Table 7 summarizes the port pull-up default status and controls.
Table 7 Port Pull-Up, Pull-Down and Reduced Drive Summary
Port
Name
Port A
Port B
Port E:
PE7, PE3,
PE2, PE0
PE1
PE[6:4]
PE[6:5]
Port P
Port S
PS[3:2]
PS[7:4]
Port T
Port DLC
Port AD
BKGD
Resistive
Input Loads
Pull-up
Pull-up
Enable Bit
Register
(Address)
Bit Name Reset State
PUCR ($000C) PUPA Disabled
PUCR ($000C) PUPB Disabled
Reduced Drive Control Bit
Register
(Address)
Bit Name
Reset
State
RDRIV ($000D) RDPA Full Drive
RDRIV ($000D) RDPB Full Drive
Pull-up
PUCR ($000C) PUPE Enabled RDRIV ($000D) RDPE Full Drive
Pull-up
None
Pull-down
Pull-up
Pull-up
Pull-up
Pull-up
Pull-up
Pull-up
None
Pull-up
Always Enabled
—
Enabled During Reset
PWCTL ($0054) PUPP Disabled
PURDS ($00DB) PUPS0 Disabled
PURDS ($00DB) PUPS1 Disabled
PURDS ($00DB) PUPS2 Disabled
TMSK2 ($008D) PUPT Disabled
DLCSCR ($00FD) DLCPUE Disabled
—
—
—
Enabled
RDRIV ($000D) RDPE
RDRIV ($000D) RDPE
—
—
PWCTL ($0054) RDPP
PURDS ($00DB) RDPS0
PURDS ($00DB) RDPS1
PURDS ($00DB) RDPS2
TMSK2 ($008D) RDPT
DLCSCR ($00FD) DLCRDV
—
—
—
Full Drive
Full Drive
—
Full Drive
Full Drive
Full Drive
Full Drive
Full Drive
Full Drive
Full Drive
MC68HC912B32
MC68HC912B32TS/D
MOTOROLA
19