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I LOVE Retroshields! Not because I made them but they makes debugging HW/SW so easy and very educational. Recently, I was bringing up the Retroshield 6800 prototype. I quickly got MIKBUG and SWTBUG running. Next step was to run FLEX 2.0 using the DSK images on Teensy sdcard. That’s where my life felt like a “going down the drain”… I spent 2 weeks with no progress. Until…
Typical transputer reference designs use IMS C011 (or IMS C012) link adapter chips (from INMOS) to connect the transputer to a HOST (PC) where the iserver application downloads the boot code and afterwards provides storage/console services over the link. Links use two types of messages: [11-bit message for 8-bit DATA] and [2-bit message for ACK]. The difference is the bit following the start bit…
RetroShield 8008 Presentation ( html, pdf )
Quick Links www.4004.com for lots of info on Intel 4004 processor. Busicom 141-PF ROM images disassembled, commented and documented Busicom 141-PF story on vintage calculator site Busicom 141-PF page on vintage calculator site Credits I like to thank following for extracting rare ROM images and making them available for public: www.4004.com team 4004 design team Computer History Museum Tim…
Let me tell you why I did RetroShield. Way back in time I grew up in 1980’s when 8bit microprocessors were all around. For some reason my dad chose 6502 based Oric Atmos for our first computer instead of the more popular Spectrum ZX. It ended up being agood choise because there were no games for Oric and the only thing I could do was learn how to program in BASIC.
8031, 8085A and 1802 RetroShields are alive now. Pictures at the end. 8031 is running Paulmon2, a monitor code by Paul :) at PJRC, original teensy website. 8085A is running Mon85, a capable monitor originally by Dave Dunfield and improved by Roman Borik. 1802 is running tinyBASIC + IDIOT mon from Lee Hart’s “1802 Membership” website. Considering I never used these processors…
If you don’t need the additional GPIO’s on Arduino Mega, you can instead use Teensy adapter for more memory and faster speeds. As I mentioned earlier, Microchip 23LC1024 is an SPI RAM with 128KBytes, giving us 2 banks of 64KBytes. Since I also want to enable file I/O and RTC for RetroShield, best option was reworking a 23LC1024 to Adafruit SD Card Logger Shield. What you need: Adafruit…
If you don’t need the additional GPIO’s on Arduino Mega, you can instead use Teensy adapter for more memory and faster speeds. This blog talks about adding 128 KBytes to Arduino Mega w/ SPI and some of learnings thru the process. SPI-RAM (23LC1024, 128KBytes, SPI) I chose Arduino Mega because of its 5V GPIO’s but it has only 8KB RAM. My goal was to keep the design simple (no…
Well, look what I got. 3 new RetroShields for 1802, 8031, and 8085. Work is busy lately but I will work on these as fast as possible. PS: The green mask on 8085 PCB was my mistake during ordering. Oh well, that’s why we build prototypes first :)
Interesting article at digikey about 8-bit microcontrollers: https://www.digikey.com/en/blog/the-8-bit-microcontroller-is-still-a-great-option-for-low-power-and-ease-of-use
Once in a while, I truly come across saying great minds think a like. While googling, I came across two impressive projects: Dave C. had done a Arduino/6502 project that connects 6502 to Arduino. He has bread-boarded a 6502 and emulates Apple-1. His project is better than mine because it runs faster (300kHz vs 165kHz RetroShield) but I might have beaten him by a few months because my first proto…
Updated if opengl is disabled in VcXsrv, then pcb-gtk & pcb-rnd seem to work fine. I am able to run gschem and pcb on Windows 10 using Windows Linux Subsystem. Here are the steps I followed: Install Windows Linux Subsystem Follow instructions on this website to install.Optionally install the Ubuntu fonts. How to Install and Use the Linux Bash Shell on Windows 10 Run Ubuntu shell, go thru the setup…
I used many schematic capture tools but the one that always stuck with me was Concept from Cadence back in 1999-2006 (aka Allegro HDL Design Entry, example). Many aspects felt natural to me, including screen/page/UI design, keyboard and mouse assignments, command line entry, library management, ascii files and hence scriptable, library management, keyboard and mouse assignments, scriptable,…
Ok, this article is for those people who want to write and assemble their own assembly code, and then run it on the RetroShield. I’m going to start w/ Z80 but the process is similar with others. You need the following pieces: Text Editor Microprocessor Hardware Design Assembler Microprocessor Firmware Arduino IDE For this tutorial, we will write a simple UART Echo code for Z80. Text Editor…
As a use request, I brought up KIM-1 on RetroShield 6502. The hardest part was emulating 6530 chip, which has RAM and timers. But it works. KIM-1 code is on the gitlab. Enjoy Links KIM-1 Documents 6530 Chip Micro-Kim
I don’t expect to make a living from RetroShield but this Sunday I had an unusual surge of orders. I didn’t know what happened. As I was printing the labels, I realized it must have been hackaday.com because I had submitted my project there. It’s an honor to be featured on hackaday.com. Well, I got several emails and feedback (thanks for all). I had to work on my other projects,…
I had a dilemna when I designed RetroShield. At one hand, I wanted to use thru-hole parts so it will be easier to assemble. On the other hand, CLK trace is critical and I wanted to use surface-mount components for signal conditioning. I spent about a week thinking about this in the background. Eventually, surface-mount components won, because i) it had to work reliably, ii) bigger parts, size…
At the time I was thinking about RetroShield, I read other people trying RPI as their main computer. The reviews were mixed, so I asked myself, why not? I used RPI for about 2 months and I believe it has a lot of potential for daily use with some gotchas. TL;DR version Raspberry pi is dead slow compared to your Intel laptop, but if you make the following upgrades, it is very useful.
Ok, we connect an 8-bit microprocessor to Arduino Mega, but how does it really work? Let’s answer that for 6502: Arduino Mega to 6502 connections. Cycle-by-cycle operation of 6502 Memory maps IO device(s) Arduino to 6502 connections Arduino Mega is connected to the 6502 as follows. Arduino will drive the clock signal high <-> low, and during each cycle will look at the uP control signals…
6809 (Sixty-Eight-Oh-Nine) 6809 has a special place in my heart because once you read the specs, you start drooling immediately. I think 6809 is a 16bit transition squeezed into 8bit bus package. Two 8-bit Accumulators (A,B) that can be combined to form one 16-bit Accumulator (D) Two 16-bit Indexable Stack Pointers (S, U) Program Counter Relative Auto-increment/Decrement by 1 or 2 8x8 unsigned…
I’m excited to announce a very cool project for retromaniacs: A real 8 bit microprocessor connected to Arduino or Teensy Build your 8-bit microprocessor project as simple as writing Arduino Code. Make system hardware changes quickly by modifying Arduino code. Works with Arduino Mega (cheap, easy) or Teensy 3.5/3.6 (faster, more memory). Open source hardware and software (see below for…
Simon6809-Turbo is an improved version of Simon6809, so I can run FLEX 6809 operating system. This project is retired and shown for educational value. Simon6809-Turbo grow out of a curiosity to run FLEX operating system. modular board design (CPU + PIA + USB/SDCARD + …) 512KB RAM (w/ memory banking since 6809 can only see 64KB) ShadowRAM for ROM code. support for multiple PIA and I/O…
SiMon6809 is a 6809 based educational computer. If you coded on 8-bit processors, you will remember the good-ol' days. If you never used an 8-bit processor, you can use SiMon6809 to go back in time. This project is retired and shown for educational value. Check out RetroShield for Arduino instead. Back in the days of Apple I/II and Commodore 64, 6502 and its derivatives were the most popular 8-bit…
Feel free to contact me if you have any questions, comments. Growing up in 1980’s, I was impressed by two things: microprocessors and planes. I’m lucky enough to have made one career and the other my hobby. I started on Oric Atmos and then upgraded to Commodore 64. I basically spent my youth on c64 (good or bad, but it helped me get my first job - thanks Hedley! :) I remember running…
I moved the store over to tindie.com:
These are some stuff I built, some from scratch and some from kits. I’m surprised some of the really old ones from high school survived (that would be about 30 years ago). Poor Man’s EEPROM programmer This was built during high school in Istanbul. I wanted to build a z80 based board and I didn’t have a way to program the eeprom IC. No computer to assemble either. So I…