Freescale Semiconductor, Inc.
Pinout and Signal Descriptions
Port Signals
Table 3-3. Port Description Summary
Pin Numbers Data Direction
Port Name
Register
(Address)
Description
112-pin
Port A
PA[7:0]
In/Out
DDRA ($0002)
Port A and port B pins are used for address and data in
expanded modes. The port data registers are not in the
address map during expanded and peripheral mode
operation. When in the map, port A and port B can be
read or written any time.
64-57
Port B
PB[7:0]
In/Out
DDRB ($0003)
31–24
DDRA and DDRB are not in the address map in expanded
or peripheral modes.
Port AD1
PAD1[7:0]
84/82/80/78/7
6/74/72/70
In
In
Analog-to-digital converter 1 and general-purpose I/O.
Analog-to-digital converter 0 and general-purpose I/O.
Port AD0
PAD0[7:0]
83/81/79/77/7
5/73/71/69
Port CAN1
PCAN1[1:0]
PCAN1[1] Out PCAN1[1:0] are used with the MSCAN1 module and
PCAN1[0] In cannot be used as general purpose I/O.
PCAN0[1] Out PCAN0[1:0] are used with the MSCAN0 module and
102–103
104–105
98–101
Port CAN0
PCAN0[1:0]
PCAN0[0] In
cannot be used as general purpose I/O.
Port IB
PIB[7:4]
In/Out
DDRIB ($00E7)
General purpose I/O. PIB[7:6] are used with the I-Bus
module when enabled.
Port IB
PIB[3:2]
In/Out
DDRIB ($00E7)
102–103
General purpose I/O
PE[1:0] In
PE[7:2] In/Out
DDRE ($0009)
Port E
PE[7:0]
Mode selection, bus control signals and interrupt service
request signals; or general-purpose I/O.
36–39, 53–56
Port K
PK[7,3:0]
13,
108-111
In/Out
DDRK ($00FD)
Page index emulation signals in expanded or peripheral
mode or general-purpose I/O.
Port P
PP[3:0]
112,
1–3
In/Out
DDRP ($0057)
General-purpose I/O. PP[3:0] are used with the pulse-width
modulator when enabled.
Port S
PS[7:0]
In/Out
DDRS ($00D7)
Serial communications interfaces 1 and 0 and serial
peripheral interface subsystems; or general-purpose I/O.
96–89
General-purpose I/O when not enabled for input capture
and output compare in the timer and pulse accumulator
subsystem.
Port T
PT[7:0]
In/Out
DDRT ($00AF)
18–15, 7–4
MC68HC912DG128 — Rev 3.0
Technical Data
Pinout and Signal Descriptions
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