Design Of An 8-bit Microcontroller Compatible With Intel MCS-51 Series

In this paper, an 8-bit Microcontroller is designed and implemented by Top-Down IC design method. Its instruction set is compatible with that of INTEL MCS-51 series, which includes 111 instructions and can fulfill various tasks. But it adopts Harvard Bus and Two-level pipeline structure, so its operating speed is greatly increased. Therefore, it can be used in those microcontrolling fields requiring high speed and high ratio of performance to price.This microcontroller has abundant hardware resources, including twenty-one SFRs, four 8-bit input-output ports, two 16-bit timer/counters, one full-duplex serial port, five interrupting sources and two-level priority nesting. Besides, it also has eight flexible addressing modes. The design thoughts and implementing processes are fully discussed in the thesis. It is divided into three parts. First, the front-end design is detailedly narrated, including system specification, compartmentalization and designs of modules, instruction set and functional simulation; the second part emphasizes on problems met in synthesis and their corresponding measures, then mentions a popular simulating tool: ModelSim; the third part consists of placing and routing, post-simulation, etc. The accomplishment of this microcontroller can settle a strong base to design other ASICs and implement system integration. I have independently accomplished the following tasks: writing specification and source code, functional simulation, synthesis, pre-layout simulation, and tried placing and routing, post-simulation. Based on the analyses of circuits and instructions, I also wrote some assembling programs, translated them into hexadecimal codes, and then put them into ROM to verify logic functions of the whole system. Now, the design and all the instructions have been validated successfully.