Datasheet

Pinout and Signal Descriptions
Technical Data MC68HC912DT128A — Rev 4.0
56 Pinout and Signal Descriptions MOTOROLA
3.5 Port Signals
The MC68HC912DT128A incorporates eleven ports which are used to
control and access the various device subsystems. When not used for
these purposes, port pins may be used for general-purpose I/O. In
addition to the pins described below, each port consists of a data register
which can be read and written at any time, and, with the exception of port
AD0, port AD1, PE[1:0], RxCAN and TxCAN, a data direction register
which controls the direction of each pin. After reset all general purpose
I/O pins are configured as input.
3.5.1 Port A
Port A pins are used for address and data in expanded modes. When
this port is not used for external access such as in single-chip mode,
these pins can be used as general purpose I/O. The port data register is
not in the address map during expanded and peripheral mode operation.
When it is in the map, port A can be read or written at anytime.
Register DDRA determines whether each port A pin is an input or output.
DDRA is not in the address map during expanded and peripheral mode
operation. Setting a bit in DDRA makes the corresponding bit in port A
an output; clearing a bit in DDRA makes the corresponding bit in port A
an input. The default reset state of DDRA is all zeroes.
When the PUPA bit in the PUCR register is set, all port A input pins are
pulled-up internally by an active pull-up device. PUCR is not in the
address map in peripheral mode.
SDA PIB6 99
I
2
C bus serial data line pin
KWJ[7:0] PJ[7:0]
8–11,
19–22
Key wake-up and general purpose I/O; can cause an interrupt when an input
transitions from high to low or from low to high (KWPJ).
KWH[7:0] PH[7:0]
32–35,
49–52
Key wake-up and general purpose I/O; can cause an interrupt when an input
transitions from high to low or from low to high (KWPH).
1. MC68HC912DT128A only
Table 3-2. MC68HC912DT128A Signal Description Summary
Pin Name
Shared
port
Pin
Number
Description
112-pin
Frees
cale Semiconductor,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
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