Programming Model; Introduction; Port B Signals And Registers; Port C Signals And Registers - Motorola DSP56305 User Manual

5.1

INTRODUCTION

The DSP56305 provides forty-two bidirectional signals that can be configured as General
Purpose Input/Output (GPIO) signals or as peripheral dedicated signals. No dedicated
GPIO signals are provided. All of these signals are GPIO by default after reset. The
control register settings of the DSP56305's peripherals determine whether these signals
are used as GPIO or as peripheral dedicated signals. This section describes how signals
may be used as GPIO.
5.2

PROGRAMMING MODEL

The Signals Description section (Section 2) of this manual describes the special uses of
these signals in detail. There are five groups of these signals. They can be controlled
separately or as groups. The groups are:
• Port B: twenty-four GPIO signals (shared with the HI32 signals)
• Port C: six GPIO signals (shared with the ESSI0 signals)
• Port D: six GPIO signals (shared with the ESSI1 signals)
• Port E: three GPIO signals (shared with the SCI signals)
• Timers: three GPIO signals (shared with the Triple Timer signals)
5.2.1

Port B Signals and Registers

Twenty-four Port B signals when not used as HI32 signals can be configured as GPIO
signals. The GPIO functionality of Port B is controlled by three registers: DSP Control
Register (DCTR), DSP Host Port GPIO Direction register (DIRH), and DSP Host Port
GPIO Data register (DATH). These registers are described in Section 6 of this document.
5.2.2

Port C Signals and Registers

Each of the six Port C signals not used as an ESSI0 signal can be configured individually
as a GPIO signal. The GPIO functionality of Port C is controlled by three registers: Port C
Control Register (PCRC), Port C Direction Register (PRRC), and Port C Data Register
(PDRC). These registers are described in Section 7 of this document.
MOTOROLA DSP56305 User's Manual
General Purpose I/O
Introduction
5-3