Motorola DSP56012 - Manual (Page 207)

GPIO
Introduction
MOTOROLA DSP56012 User’s Manual 7-3
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 eight I/O pins
(GPIO0–GPIO7) that are controlled through a memory-mapped register. Each GPIO
pin 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.
7.3 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.
Figure 7-1 GPIO Control/Data Register
GD0
0
GPIOR
X:$FFF7
GD1
1
GD2
2
GD3
3 4 5 6 7
GDD0
8
GDD1
9
GDD2
10
GDD3
11 12 13 14 15
GC0
16
GC1
17
GC2
18
GC3
19 20 21 22 23
AA0441.11
GD4 GD5 GD6 GD7
GDD4 GDD5 GDD6 GDD7
GC4 GC5 GC6 GC7