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Original Publication Date: 1999-Jan-01
Included in the Prior Art Database: 2002-Jul-24

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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.