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ArduZ80

The first Z80 emulation library for Arduino, bringing back the old Z80 to life.

Now Available on the Arduino LibraryManager & Arduino Playground

Introduction

Studying microprocessors for a semester project, I had to write an emulator, and I chose Z80 to be my study case. my project had to be in arduino, so the emulator itself must run on arduino, I searched the internet and no working project or library where found for Z80 to emulate it on arduino, I decided to write my own library and emulator system and revive the Z80 through Arduino, it was a great processor for hobbyists and students and very good to study computer architeture on it.

Zilog Z80

The Z80 microprocessor is an 8 bit CPU with a 16 bit address bus.
It has a language of 252 root instructions and an additional 308 instructions.
The Z80 was modeled after the 8080 and contains the 78 opcodes of 8080 opcodes as a subset to it's language.
Programming features include an accumulator and six eight bit registers that can be paired as Three 16 bit registers.
In addition to the general registers, a stack-pointer, program-counter, and two index (memory pointers) registers are provided.

Features

  • Interpretation-Based.
  • Written and optimized for Arduino.
  • Tested on Arduino Nano, Uno, Mega.
  • ALU, Buses, Registers, Control Unit emulated.
  • Emulates 260 Instructions (177 Basic Instructions, 83 Extended Instructions).
  • Implementation of IN and OUT instruction left for developer to customize his system.
  • built with customization and extensibility in mind, adding a new instruction takes 3 lines only.

Usage

Step 1:

//Make an array to hold the program
uint8_t t[30] = {

EXT_FD, FD_LD_A_imm, 0x00,
EXT_DD, DD_LD_B_imm, 0x09,
EXT_DD, DD_LD_C_imm, 0x03,
XOR_A_B, 
XOR_A_C, 
XOR_A_imm, 0xFF,
NOP

};

Step 2 :

//Copy the program to RAM 
for (int i = 0; i < 30; i++) {

    cpu.ram_[i] = t[i];

}

Step 3 :

//Run the CPU 
cpu.run_to_nop(true);

Step 4 (Optional) :

//Implement write_io and read_io 

void ArduZ80::write_io(uint16_t addr, uint8_t val){ }

uint8_t ArduZ80::read_io(uint16_t addr){ return data; }

Credits

  • Sijmen Smulder for his C++ emulator, helped as a base for my Arduino version.
  • Gabriel Gambetta for his C library, helped to understand some instructions and tweak emulator.

License

This library is signed under MIT License, Reproduce under it's terms.