Pinout and Signal Descriptions
Port Signals
68HC(9)12DG128 Rev 1.0
MOTOROLA
Pinout and Signal Descriptions
47
23-pins
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 9
summarizes the port
pull-up/pull-down default status and controls.
Table 9 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
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
PUCR ($000C)
PWCTL ($0054)
PUPK
PUPP
Disabled
Disabled
RDRIV ($000D)
PWCTL ($0054)
SP0CR2
($00D1)
TMSK2 ($008D)
RDPK
RDPP
Full drive
Full drive
Port S
Pull-up
SP0CR2 ($00D1)
PUPS
Enabled
RDPS
Full drive
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]
Pull-up
Pull-up
Pull-up
None
None
None
Pull-up
None
Pull-up
TMSK2 ($008D)
IBPURD ($00E5)
Always enabled when pins are input
—
—
—
Always enabled
—
Always enabled
TPU
PUPIB
Disabled
Disabled IBPURD ($00E5)
IBPURD ($00E5)
TDRB
RDPIB
RDPIB
—
—
—
—
—
—
Full drive
Full drive
Full drive