Figure 7-1 Gpio Control/Data Register; Introduction - Motorola DSP56009 User Manual

7.1

INTRODUCTION

The General Purpose Input/Output (GPIO) pins are used for control and handshake
functions between the DSP and external circuitry. The GPIO port has four I/O
signals (GPIO0–GPIO3) that are controlled through a memory-mapped register. Each
GPIO signal may be individually programmed as an output or as an input.
7.2 GPIO PROGRAMMING MODEL
The GPIO pins are controlled through the GPIO control/data Register (GPIOR),
which is illustrated in Figure 7-1 . The register is described in the following
paragraphs.
7
15
23
Reserved Bit
7.3 GPIO REGISTER (GPIOR)
The GPIO Register (GPIOR) is a 24-bit read/write control/data register used to
operate and configure the GPIO pins. The control bits in the GPIOR select the
direction of data transfer for each pin, whereas the data bits in the GPIOR are used to
read from or write to the GPIO pins. Hardware reset and software reset clear all the
bits in GPIOR. The GPIOR bits are described in the following paragraphs.
MOTOROLA
6 5 4
GD3
14 13 12 11
GDD3
22 21 20 19
GC3

Figure 7-1 GPIO Control/Data Register

DSP56009 User's Manual
General Purpose Input/Output
3 2 1 0
GD2 GD1 GD0
10 9 8
GDD2 GDD1 GDD0
18 17 16
GC2 GC1 GC0
Introduction
GPIOR
X:$FFF7
AA0441
7-3