Pinout and Signal Descriptions
Technical Data
MC68HC912DG128 — Rev 3.0
60
Pinout and Signal Descriptions
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MOTOROLA
3.5.15 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 3-4
summarizes the port pull-up/pull-
down default status and controls.
Table 3-4. Port Pull-Up, Pull-Down and Reduced Drive Summary
Enable Bit
Reduced Drive Control Bit
Register
(Address)
RDRIV ($000D)
RDRIV ($000D)
Port
Name
Port A
Port B
Port E:
PE7, PE[3:2]
PE[1:0]
PE[6:4]
Resistive
Input Loads
Pull-up
Pull-up
Register
(Address)
PUCR ($000C)
PUCR ($000C)
Bit Name
Reset
State
Disabled
Disabled
Bit Name
Reset
State
Full drive
Full drive
PUPA
PUPB
RDPA
RDPB
Pull-up
Pull-up
None
Pull-up or
Pull-down
Pull-up or
Pull-down
Pull-up
Pull-up
Pull-up
Pull-up
Pull-up
Pull-up
None
None
None
Pull-up
None
Pull-up
PUCR ($000C)
PUCR ($000C)
PUPE
PUPE
Enabled
Enabled
RDRIV ($000D)
RDPE
—
RDPE
Full drive
—
RDRIV ($000D)
Full drive
Port H
PUCR ($000C)
PUPH
Disabled
RDRIV ($000D)
RDPH
Full drive
Port J
PUCR ($000C)
PUPJ
Disabled
RDRIV ($000D)
RDPJ
Full drive
Port K
Port P
Port S
Port T
Port IB[7:4]
Port IB[3:2]
Port AD0
Port AD1
Port CAN1[1]
Port CAN1[0]
Port CAN0[1]
Port CAN0[0]
PUCR ($000C)
PWCTL ($0054)
SP0CR2 ($00D1)
TMSK2 ($008D)
IBPURD ($00E5)
Always enabled when pins are input
—
—
—
Always enabled
—
Always enabled
PUPK
PUPP
PUPS
TPU
PUPIB
Disabled
Disabled
Enabled SP0CR2 ($00D1)
Disabled
TMSK2 ($008D)
Disabled IBPURD ($00E5)
IBPURD ($00E5)
RDRIV ($000D)
PWCTL ($0054)
RDPK
RDPP
RDPS
TDRB
RDPIB
RDPIB
—
—
—
—
—
—
Full drive
Full drive
Full drive
Full drive
Full drive
Full drive
F
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