Motorola ColdFire MCF5281 - Manual (Page 504)

General Purpose I/O Module
26-4 Freescale Semiconductor
26.1.1 Overview
The ports module controls the configuration for various external pins, including those used for:
• External bus accesses
• Chip selects
• Debug data
• Processor status
• Ethernet data and control (not present on the MCF5214 and MCF5216)
• FlexCAN transmit/receive data
• I
2
C serial control
• QSPI
• SDRAM control
• 32-bit DMA timers
• UART transmit/receive
26.1.2 Features
The ports includes these distinctive features:
• Control of primary function use on all ports
• Digital I/O support for all ports
— Registers for storing output pin data
— Registers for controlling pin data direction
— Registers for reading current pin state
— Registers for setting and clearing output pin data registers
26.1.3 Modes of Operation
The operational modes for the ports are listed below. For more detailed descriptions of each mode, refer
to
Section 26.4, “Functional Description .”
• Single-chip mode
All pins are configured as digital I/O by default, except for debug data pins (DDATA[3:0]) and
processor status pins (PST[3:0]).
• Master mode
Ports A and B function as the upper external data bus. Ports C and D can function as the lower
external data bus. Ports E–J are configured to support external memory.
26.2 External Signal Description
The ports control the functionality of several external pins. These pins are listed in Table 26-1 .
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3