GENERATING DIRECT I/O FROM AN INSTRUCTION SET SIMULATOR

Publication Summary

One of the main drawbacks of an instruction set simulator is the lack of any direct I/O, in particular Development systems based on instruction set physical I/O. A simulator uses a software-simulated simulators are becoming increasing popular in the memory map and as such has no direct contact with embedded microcontroller world. However, instmc- the target system. It is unlikely that the simulator tion set simulators cannot currently provide direct will have direct access, or an interface, to a physical I/O from the host machine. This document aims to communications port with the same characteristics discuss and present a generic solution to the prob- as those used by the device being simulated. lems encountered when implementing direct I/O with an instruction set simulator, particularly the This document defines a generic concept for implementation of direct physical I/O. providing direct I/O for simulators and provides an implemented example of the concept applied to INTRODUCTION -HARDWARE AND physical I/O with a hardware target. SOFIWARE DEVELOPMENT SYSTEMS CONCEPT The availability of a development system, while the microcontroller it emulates is still in the design By inserting a peripheral I/O system to act as a phase allows the software developer to design, write translator between the host system and the target and test the application software before samples of system a communication link can be created. This the microcontroller are available. allows the simulator to communicate with a periph- eral system, which, in turn, enables communication An instruction set simulator uses a software with the target system (see Figure 1). model to mimic the actions of a microcontroller.

Country	United States
Language	English (United States)
Copyright	Motorola Inc. January 1999

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M-LA Technical Developments

GENERATING DIRECT I/O FROM AN INSTRUCTION SET SIMULATOR

ABSTRACT One of the main drawbacks of an instruction set simulator is the lack of any direct I/O, in particular

  Development systems based on instruction set physical I/O. A simulator uses a software-simulated simulators are becoming increasing popular in the memory map and as such has no direct contact with embedded microcontroller world. However, instmc- the target system. It is unlikely that the simulator tion set simulators cannot currently provide direct will have direct access, or an interface, to a physical I/O from the host machine. This document aims to communications port with the same characteristics discuss and present a generic solution to the prob- as those used by the device being simulated.
lems encountered when implementing direct I/O
with an instruction set simulator, particularly the This document defines a generic concept for implementation of direct physical I/O. providing direct I/O for simulators and provides an implemented example of the concept applied to

INTRODUCTION -HARDWARE AND physical I/O with a hardware target. SOFIWARE DEVELOPMENT SYSTEMS

CONCEPT

  The availability of a development system, while the microcontroller it emulates is still in the design By inserting a peripheral I/O system to act as a phase allows the software developer to design, write translator between the host system and the target and test the application software before samples of system a communication link can be created. This the microcontroller are available. allows the simulator to communicate with a periph- eral system, which, in turn, enables communication

An instruction set simulator uses a software with the target system (see Figure 1). model to mimic the actions of a microcontroller.

However, for any development system to be used The host system is any computer system capable throughout all stages of software development, it of running the simulator software and the Dynamic should be capable of being connected to a target Link Library (DLL) software. Typically, the host system. will be a PC running the Windows '95 or Windows

NT operating system.

Fig. 1 I/O design concept for instruction set simulator

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MoloRoLA Technical Developments

THE CONCEPT APPLIED TO A HARDWARE TARGET

  For I/O simulation using a hardware target, an I/O Dynamic Link Library (DLL) component is required on the host system. This DLL links the simulator core (using an Application Programming Interface (API)) to the port driver (also using an API). Communication with the Peripheral System is handled by a communications protocol. The exter- nal interface could be a serial port, a parallel port, SCSI bus, TCP/IP, or other interface that provides a connection to the Peripheral I/O System.

  The Peripheral I/O System provides an interface to the host system, using' the communications proto- col, and an int...

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