mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 399

• Manufacturer Part Number: mcf51ac256a
• Description: Mcf51ac Flexis
• Manufacturer: Freescale Semiconductor, Inc

Chapter 17
Rapid GPIO (RGPIO)
17.1
The Rapid GPIO (RGPIO) module provides a 16-bit general-purpose I/O module directly connected to the
processor’s high-speed 32-bit local bus. This connection plus support for single-cycle, zero wait-state data
transfers allows the RGPIO module to provide improved pin performance when compared to more
traditional GPIO modules located on the internal slave peripheral bus.
Many of the pins associated with a device may be used for several different functions. Their primary
functions are to provide external interfaces to access off-chip resources. When not used for their primary
function, many of the pins may be used as general-purpose digital I/O (GPIO) pins. The definition of the
exact pin functions and the affected signals is specific to each device. Every GPIO port, including the
RGPIO module, has registers that configure, monitor, and control the port pins.
17.1.1
The RGPIO module provides 16-bits of high-speed GPIO functionality, mapped to the processor’s bus.
The key features of this module include:
A simplified block diagram of the RGPIO module is shown in
and pad logic are device-specific.
Freescale Semiconductor
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16 bits of high-speed GPIO functionality connected to the processor’s local 32-bit bus
Memory-mapped device connected to the ColdFire core’s local bus
— Support for all access sizes: byte, word, and longword
— All reads and writes complete in a single data phase cycle for zero wait-state response
Data bits can be accessed directly or via alternate addresses to provide set, clear, and toggle
functions
— Alternate addresses allow set, clear, toggle functions using simple store operations without the
Unique data direction and pin enable control registers
Package pin toggle rates typically 1.5–3.5x faster than comparable pin mapped onto peripheral bus
Introduction
need for read-modify-write references
Overview
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
Figure
17-1. The details of the pin muxing
17-1