
Pinout and Signal Descriptions
Port Signals
MC68HC912DT128A Rev 2.0
MOTOROLA
Pinout and Signal Descriptions
49
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 1
summarizes the port pull-up default
status and controls.
Port P
PP[3:0]
Port S
PS[7:0]
Port T
PT[7:0]
112,
1
–
3
In/Out
DDRP ($0057)
In/Out
DDRS ($00D7)
In/Out
DDRT ($00AF)
General-purpose I/O. PP[3:0] are used with the pulse-width
modulator when enabled.
Serial communications interfaces 1 and 0 and serial peripheral
interface subsystems; or general-purpose I/O.
General-purpose I/O when not enabled for input capture and
output compare in the timer and pulse accumulator subsystem.
96
–
89
18
–
15,
7
–
4
1
MC68HC912DT128A
only
2
MC68HC912DG128A
only
Table 7 MC68HC912DT128A Port Description Summary
Port Name
Pin
Numbers
112-pin
Data Direction
Register (Address)
Description
Table 1 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 PWCTL ($0054)
RDRIV ($000D)
RDPK
RDPP
Full drive
Full drive
Port S
Pull-up
SP0CR2 ($00D1)
PUPS
Enabled
SP0CR2
($00D1)
RDPS
Full drive
Port T
Pull-up
TMSK2 ($008D)
TPU
Disabled TMSK2 ($008D)
TDRB
Full drive