Sep 02, 2012 the software side should be the easy part for me, the hardware is what i will probably learn the most from as my electronics knowledge is pretty rudimentary. So i searched for useable parts in my hardware repository and found everything necessary to build a small tiny, in fact z80 based computer. Below is the logic analyzers capture of the attobasic program that is testing ram. The z80 microprocessor kit is designed for selflearning how to build and how to. Z80 project with avr system controller z80 retro computing. So i searched for useable parts in my hardware repository and found everything necessary to build a. The z80 is so stable that it can actually be stopped at a standstill and still not lose its data. Net windows application that allows us to transfer data to and from the rom chip being programmed. Heres a z80 tester circuit wired up on my breadboard. If you used a z80 chip back in the 1980s, it almost certainly passed through this room. To store our program i had 2 eeprom chips, an at28c256 from atmel. Repair procedures june 2011 display module rev e this table lists the various screens and menu options of the operating software.
Most of the z80 software ive seen initially assigns to sp the highest ram address. This test circuit will place a logical low on each bit of the data bus. Cable detect is taken care of in software so these are not currently needed, but i broke them out just in case. Best tool for self learning the basic of todays computer. Zilog z80 microprocessor chip test circuit youtube. Build a mini 4mhz z80 64kb ram system with basic and forth interpreters, cpm 2. Sign up no description, website, or topics provided. If you do so, however, you must connect the button to the clock input pin through some stabilizing circuitry so that it produces a clean rise and fall, instead of a. Go figure when i was able to sit down and start the build process, i set out to populate and solder a test and development unit.
The creation of a simple library to drive the z80 along with some testprograms. You can definitely do multitasking on z80, ive seen projects that do it. The z80 membership card an altair in an altoids tin. Sdcc is a retargettable, optimizing standard c ansi c89 iso c90, iso c99, iso c11 c17 compiler that targets a growing list of processors including the intel 8051, maxim 80ds390, zilog z80, z180, ez80 in z80 mode, rabbit 2000, gameboy, motorola 68hc08, s08, stmicroelectronics stm8 and padauk pdk14 and pdk15 targets.
This means that the z80 can read or write up to 8 bits at a time while being able to access up to 65536 individual locations by using the address bus. Jela compiler 6502z806809 a portable secondgeneration programming language. But certainly there wasnt anything like tagged types, or dispatching, or preconditions. But anyway, the z80 is a good choice for your project. The only way to do this was to build a tester, building a whole computer would have been out of the question. The four independently programmable channels of the z80 ctc satisfy common microcomputer. Despite that it will be designed for old z80 home devices i. General description the z80 ctc, hereinafter referred to as z80 ctc or ctc, applica tions. The z80 microprocessor kit is designed for selflearning how to build and how to program the z80 microcomputer. I love z80s for what they were in their time, but one cheap part from microchip can run rings around the thing with many many advantages.
The software side should be the easy part for me, the hardware is what i will probably learn the most from as my electronics knowledge is pretty. Above photo shows a populated z80 ice board with ribbon serial cable and 40pin dip plug attached. To be sure, always make the clock high right after making it low. Zmac assember is used to generate z80 program test snippets which are then run in. Otherwise its a standard z80 circuit interfaced with static ram, rom and the keyboard peripheal circuit.
Z80 simulator ide is powerful application that supplies z80 microprocessor users and educators with userfriendly graphical development environment for windows with integrated simulator emulator, z80 basic compiler, assembler, disassembler and debugger for the zilog z80 8bit microprocessor. That board is based on the old intersystems ii cpu board. If youre looking for a simple circuit to build, and youd like to have your own homemade z80 computer. Build incrementally, start with the z80 test circuit, wire up a eeprom so it can run some code and just build from there.
This application note gives a description of a circuit design allowing the classic z80 microproces sor to access expanded memory, beyond the 64k bytes made readily available by its 16 address lines, a0. This board implements a classic z80 microprocessor test circuit. How do i build a computer with a z80 microprocessor. The absolute minimum z80 cpu test circuit ever seen. Sep 23, 2017 added breakout pins around the z80 on my personal computer allow me to prototype circuits and test them with the inout commands in basic. Below is the realized schematic for the z80 test circuit. Inspired by nicolet paratronics nice z80 incircuit emulator, but with improved. Early version of the hardware with the z80, 128kb flash eeprom and single 32kb sram ics on breadboard. This board does not provide impedance matching, attenuation or filtering. Z80 cpu test circuit electronics forum circuits, projects. Uart is software control for low speed asynchronous communication.
The zilog z80 is a softwarecompatible extension and enhancement of the intel 8080 and, like it, was mainly aimed at embedded systems. I dont remember offhand precisely what ada features were available on that compiler. Z80 microprocessor incircuit emulator design tauntek. Feb 09, 2014 below is the realized schematic for the z80 test circuit. The program counter increments and the activity on the address lines is visualized using leds. Oct 21, 2016 arduino and zilog z80 author gdevic published on february 16, 2014 october 21, 2016 16 comments on arduino and zilog z80 if you want to find out exactly what a venerable z80 is doing on its bus while executing instructions, in this post i outlined a dongle and the software that will let you see that. In fact, you can even set up a circuit to handclock it with a pushbutton switch. A z80 test circuit the z80 pinout shows just how simple this is to hook up and at least test pc increment on nop instructions.
Circuit test software free download circuit test top 4 download offers free software downloads for windows, mac, ios and android computers and mobile devices. Z80 microcomputer kits i have for sale educational 8bit computer kits which use the z80 for the central processing unit cpu. Although used in that role, the z80 also became one of the most widely used cpus in desktop computers and home computers from the 1970s to the mid1980s. For this test i purchased a z80 pio, a programmable parallel inputoutput. Az80 is a conceptual implementation of the venerable zilog z80 processor. Besides, the thomas scherrer z80 family official support page has a section devoted to circuit schematics based upon the z80 processor. Dec 22, 2015 for the love of physics walter lewin may 16, 2011 duration. Ultimately i want to end up with a z80 test circuit that allows me to switch between three clock modes. This makes a very simple keyboard reading circuit, and all the complicated things like debouncing were done in the software. To start with i want to build the most basic test circuit i can find. Lcd module is optional, the kit provides a 16pin header. They offer higher system throughput and more efficient memory utilization than comparable second and thirdgeneration microprocessors. The zilog z80 is a software compatible extension and enhancement of the intel 8080 and, like it, was mainly aimed at embedded systems. Best circuit simulation software for electronics engineers.
I found a wonderful website that details many aspects of the z80. The zilog z80 cpu family of components are fourthgeneration enhanced microprocessors with exceptional computational power. Dont leave the clock signal in its low state for any extended periods of time or the z80 will forget its state. Limited testing at 6 and 8 mhz briefly tested at 9 mhz. The teensy is 5v tolerant, but some of the analog pins are 3v3 input only, so i wanted to make sure. I never actually built or programmed a z80 machine, but the basic knowledge was readily applicable to 6502 and 8088 hardware and software, and even to todays microcontrollers. Reset is connected to a pull up resistor and a button as described above. On one of these pages, there was a small circuit that would test the cpu, the minimum z80 tester. Z80 cpu test circuit electronics forum circuits, projects and.
Times when writing software meant writing assembler code and not installing several gb of a development package which creates files no smaller than several mb. For the love of physics walter lewin may 16, 2011 duration. Early ram test using a picaxe28x1 microcontroller to record and play back an analogue signal. Feb 12, 2017 those books were extremely clearly written, and even today provide the foundation of my knowledge of microprocessors and digital logic. The zilog z80 is a softwarecompatible extension and enhancement of the intel 8080. Z80pascal will be a crossplatform pascal compiler for z80 based devices, such as msx, spectrumzx, etc. I replicated the design seen here, z80 simple circuit schematic, with minor changes. For the z80 program ram i used a 62256 32k static ram, which was mapped into the lower 32k of the z80 s 64k memory space the display ram was in the top 32k. Those books were extremely clearly written, and even today provide the foundation of my knowledge of microprocessors and digital logic. Circuit test software free download circuit test top 4. So, connect the clock pin of the cpu to the clock circuit and the reset. In the next project, we will look into making some basic z80 programs to test. They were shipped only 3 days after the 8052 sbc pcbs but arrived 10 days later. Teensy z80 part 1 intro, memory, serial io and display.
A large change is that we are using the circuit we built in the last post to drive the clock pin of the z80. I am no longer offering any parts, but all design files needed to build your own are here. Jul, 2014 minimal test circuit for a z80 microprocessor chip. I created these kits in response to requests by site visitors for an simple way to build z80based computers.
The z80 processor is an 8bit cpu with an 8bit data bus and a 16bit address bus. Efexv4 is a monitor rom with inline assembler and disassembler andbasic utilities to write, run and debug your z80 programs in real hardwareefexmon do not needs cpm, n8vem or other complicated hardware. Driving a z80 chip with a slow clock cool, lots of good info for. Minimal test circuit for a z80 microprocessor chip. Z80 shared library including some nice testprojects. The mk 3880 mostek cpu technical manual its the z80 implementation from mostek has a section called hardware implementation examples which may help you besides, the thomas scherrer z80family official support page has a section devoted to circuit schematics based upon the z80 processor if you are in facebook, there is a group devoted to share knowledge about system design on the z80. Added breakout pins around the z80 on my personal computer allow me to prototype circuits and test them with the inout commands in basic. This photo is of the first fairchild sentry 610 test system at mostek we tested every z80 chip including zilog branded ones in this room for many years. Inspired by classic 8bit computers like the altair 8800 and heathkit h8, it is thoroughly documented and easy to build, with big parts, big pads, and big traces and spaces. The first thing to do was attempt to run the test circuit and the z80 at 3. This is a simple circuit to test the functioning of a zilog z80 cpu. Two output pins that will be helpful in our test circuit are halt and m1 which. The membership card is a complete computer that fits in an altoids tin.
The tester i built was inspired by information found here. You can also test what happens at powerup, with or without clock applied. More information about z80 test circuits can be found here. I love z80 s for what they were in their time, but one cheap part from microchip can run rings around the thing with many many advantages. As i sit here at my desk i can touch my homemade uv eraser i used endlessly to prepare an eprom to load for the next attempt. I wanted a z80 circuit that is proven and works with almost every vintage s100 board out there. Using the pot we can then vary the frequency of operation between 5.
First the program prints out a few strings to form a header on the terminal screen, much like many of the rom monitors in older computers. The pc boards can be purchased directly from express pcb by downloading and installing their software see below. The software side should be the easy part for me, the hardware is what i will probably learn the most from as my electronics knowledge is pretty rudimentary. This might sound complicated, but in the end its just not all that bad. With my previous history of using z80 assembly language building something. Z80 schematic this is a system example with parallel, serial, ram and rom z80 schematic protel the schematic above in the original protel format. After all, that will be the final goal, to use the avr as a host controller with the z80 incircuit. All data pins are pulled low, causing it to execute. You will see that the z80 cpu need a few clocks to execute the reset. I then decided to expand upon that by testing the ram with the z80 incircuit. Z80 project with avr system controller z80 retro computing with. The data lines are pulled to ground to emulate reading a string of nops from memory, and the clock is pulsed manually to single step fetching. When i asked about programming the z80 itself, well, let me think here.
Z80, z180, z280, z380, programming, hardware, software, utilities, faq, support, cpu, assembler software development tools for z80 family if there are more software development tools for z80 family, you know of or you would like to point to, please tell me. These microcomputer kits are based on designs made popular by steve ciarcia in his book build your own z80 computer, byte books, 1981. I wrote a small z80 program and loaded it into ram for the z80 to run and it. This data byte made up of each individual low bits, 00000000. The test program that i have implemented demonstrates two z80 assembly subjects, interrupts and strings. I never actually built or programmed a z80 machine, but the basic knowledge was readily applicable to 6502 and 8088 hardware and software, and even to. To test the address, data and system control buses, i initially wrote a program to set the avrs io ports, then with the z80 removed from the circuit, i wrote data to the ram, read the data back from the ram, incremented the address bus and repeated the cycle for all 65,536 bytes of ram. You could get a hard drive for it for about 400 dollars and it stored 40 megabytes of data yes that is megabytes not gigabytes. If you will see a nice pcb version that floris made click here.
S100 z80 sbc description i decided to go with a z80 over the 80808085 cpus. What is important to note here is that in testing the memory, i am also testing. Second the program halts and waits for an interrupt to be generated. View and download genie z8060 service manual online. Z80, z180, z280, z380, programming, hardware, software, utilities, faq, support, cpu, assembler. Strange things will happen if you try to give it shorter reset than clock, weird modes of opperating will then happen, eg. Quartusspecific schematic files are precompiled into generic verilog files. Back in the 1980s tandy used the z80 in their computer, called the trs80. Arduino and zilog z80 author gdevic published on february 16, 2014 october 21, 2016 16 comments on arduino and zilog z80 if you want to find out exactly what a venerable z80 is doing on its bus while executing instructions, in this post i outlined a dongle and the software that will let you see that. Once this was confirmed working, i got on to making the test circuit do additional things. I know we had some software floating point, and certainly not any tasking. Z80 tester schematics over the absolute beginner construction with a z80 cpu.