This is an 8080 simulator/emulator for an Arduino Nano. It uses about 12K of memory and appx 600 bytes of ram (dynamic memory).
This is a front panel programmable computer, something like the single board trainers used in the 70's and 80's in colleges. Using a few switches and push buttons, along with some led's and a 1x8 lcd display, you can program the memory, step thru and view memory and run 8080 programs. There is a bootloader that allows loading an 8080 object coded program over the serial port as well as some development programs written in c.
See the schematic for wiring.
There is more detail on my blog at landfallnet.blogspot.com Look for the nano80 entry.
I use a 32Kx8 FRAM for main memory. This slows it down a lot, but it gives you lots of room to play around. If you want more speed, change the fram.[read8/write8] to mem[] and set up about 1K of arduino ram. Doing this gives a speed improvement of about 4.5 times.
The serial port is defined so that your 8080 has a serial port in addition to 8 led's and 8 toggle switches for input/output.
The input/output ports are defined as follows:
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IN 0x00 is the toggle switches
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IN 0x01 is the serial port using the arduino
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IN 0x02 returns the number of available bytes on the serial port
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OUT 0x00 is the 8 LED's
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OUT 0x01 is the serial port using the arduino
========================= NOTE: The .c programs are utility programs that run on a linux computer and are not part of the arduino code. Only put the .ino file into the arduino workspace when building this project.
I posted an 8080 opcode tester in diag.asm. This is a brute-force 8080 opcode tester. I've run this over several days with good results (after I fixed the bugs).
There is a boot loader in software to load intel .hex files into the nano80 memory. Loading more than a few bytes via switches and lights get old fast. The boot loader lets you assemble large programs and upload then. See README.bootloader for use.
There are two programs used to create and send the .hexfiles:
- ihex.c
- upload.c
ihex converts the .com output of the assembler into intel .hex files. upload is a serial based uploader that allows for the slow memory access of the FRAM memory chip.
To compile these 2 programs:
- cc -o ihex ihex.c
- cc -o upload upload.c
Also here is asm80.c
This is a command line 8080 assembler I wrote some time ago. Tested under Linux, compiled with gcc. To compile:
- cc -o asm80 asm80.c
asm80 uses standard intel 8080 nmemonics. It is NOT a macro assembler.
There are some 8080 source code files for testing the system.
- sertest.asm is a simple test of the serial port.
- cylon.asm is a flashy lights program.
There is a program called dump.c This is a hex dump program I wrote to view object code files.
Compile with:
- cc -o dump dump.c
MIT license applies to all files herein unless otherwise noted.
--Kurt