MCF548x Reference Manual, Rev. 3
Freescale Semiconductor 15-1

Chapter 15

GPIO

15.1 Introduction

Many of the MCF548x pins whose primary function is to serve as the external interface to off-chip
resources may also be used for general-purpose digital I/O (GPIO) access and for one or two secondary
functions. When used for GPIO purposes, the port x pins (PXXX) indicate which port is being accessed. In
some cases, the pin function is set by the operating mode, and the alternate pin functions are not supported.
The MCF548x GPIO signals are grouped into 8-bit ports; however, some ports do not use all eight bits.
Each GPIO port has registers that configure, monitor, and control the port signals.
Figure 15-1 is a block diagram of the MCF548x GPIO module.
NOTE
The actual signals and functions available vary for different members of the
MCF548x family. See Chapter 2, “Signal Descriptions,” for more details.