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Parallel I/O Ports
MC68360 USER’S MANUAL
7.14.1 Parallel I/O Key Features
The parallel I/O ports contain the following key features:
Port A Is 16 Bits
Port B Is 18 Bits
Port C Is 12 Bits
All Ports Are Bidirectional
All Ports Have Alternate On-Chip Peripheral Functions
All Ports Are Three-Stated at System Reset
All Pin Values May Be Read While Pin Is Connected to an On-Chip Peripheral
Port A and Port B Offer Open-Drain Capability
Port C Offers 12 Interrupt Input Pins
7.14.2 Parallel I/O Overview
Each pin in the I/O ports may be configured as a general-purpose I/O pin or as a dedicated
peripheral interface pin. Port A is shared with the SCC RXD and TXD pins, the bank of
clocks pins, and some TDM pins. Port B is shared with the PIP and other functions such as
the IDMA, SMC, and SPI pins. Port C is shared with the RTS, CTS, and CD pins of the SCCs
as well as some TDM pins. Port C is unique in that its pins may generate interrupts to the
CPM interrupt controller.
Each pin may be configured as an input or output and has a latch for data output. Each pin
may be read or written at any time. Each pin may be configured as general-purpose I/O or
as a dedicated peripheral pin.
Port A and port B have pins that can be configured as open-drain—that is, the pin may be
configured in a wired-OR configuration on the board. The pin drives a zero voltage, but
three-states when driving a high voltage.
NOTES
The port pins do not have internal pullup resistors.
Due to the significant flexibility of the QUICC’s CPM, many ded-
icated peripheral functions are multiplexed onto ports A, B, and
C. The functions are grouped in such a way as to maximize the
usefulness of the pins in the greatest number of QUICC applica-
tions. The reader may not obtain a full understanding of the pin
assignment capability described in this section until attaining an
understanding of the CPM peripherals themselves.
7.14.3 Port A Pin Functions
Refer to Table 7-19 for the default description of all port A pin options. The pins marked in
boldface can have open-drain capability. Each of the 16 port A pins is independently con-
figured as a general-purpose I/O pin if the corresponding port A pin assignment register
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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