Imagine you’re time-warped back to 1979 and tasked with constructing a personal computer. Could you do it? [RadicalBrad] thinks he can, and his 6502-based “Super VIC” build looks like it’s off to a great retrocomputing start.
Most emulations of old hardware these days go the FPGA route, and while we respect those projects immensely, there’s something to be said for applying a highly artificial constraint at the outset of a project. [RadicalBrad] chose to design like it’s 1979, and limited his ode to the machines of his youth to the 6502 CPU and logic and RAM chips available before 1980. The computer will support NTSC video output and 4-channels of 8-bit sound. No circuit boards will be used – everything is to be assembled on solderless breadboards. So far he has 48 (!) of them ganged together, which sounds like an enormous amount of space to work with, but he still found things crowded enough that some of the DIP bodies were trimmed a bit to fit more closely on the breadboards. The SRAM posed a problem, though, in that the 512K chips he wanted were not available in DIPs. To stay faithful to the constraints, he soldered the SOJ-packaged RAM chips into 40-PIN DIP headers – all 25 chips! We can’t recall a PC of the era sporting 12 megabytes of RAM, but no matter – it’s too cool not to love.
[RadicalBrad] has his work cut out for him, and this could take years to finish. We’re keen to follow his progress and can’t wait till it boots for the first time. Until it does, we’ll just gaze upon such discrete computing wonders as this almost-as-simple-as-possible computer, or even this delightfully noisy adder for a relay computer.
A ruler seems like a pretty simple device; just a nice straight piece of material with some marks on it. There are some improvements out there to the basic design, like making it out of something flexible or printing a few useful crib notes and formulas on it so you have a handy reference. But for the most part, we can all agree that ruler technology has pretty much plateaued.
Well, not if [Brad] has anything to say about it. His latest creation, the Digirule2, is essentially an 8-bit computer like those of the 1970’s that just so happens to be a functional ruler as well. Forget lugging out the Altair 8800 next time you’re in the mood for some old school software development, now you can get the same experience with a piece of hardware that lives in your pencil cup.
Even if you’ve never commanded one of the blinkenlight behemoths that inspired the Digirule2, this is an excellent way to get some hands-on experience with early computer technology. Available for about the cost of a large pizza on Tindie, it represents one of the easiest and most cost-effective ways to tell your friends that as a matter of fact you have programmed a computer in binary.
The Digirule2 is powered by a Microchip PIC18F43K20, and is programmed by punching binary in one byte at a time with a bank of eight tactile switches. To make things a little easier, programs can be saved to the internal EEPROM and loaded back up just as easily thanks to the handy buttons next to the power switch. Now all you’ve got to do is figure out what all those blinking LEDs mean, and you’ll be in business.
The original Digirule was a logic gate simulator that we first covered back in 2015. We’re always happy to see projects grow and evolve over time, and think this new retro-computer themed variant is going to be quite popular with those who still love toggle switches and blinking lights.
Continue reading “Programmable Ruler Keeps 1970’s Computing Alive”
We’ll forgive you if you were busy in the ’80s, and missed the TRS80 Model 100. It was a portable version of the original, ran on four AA batteries, and even had an integrated acoustic coupler which proved handy for workers on the go. However, time is rarely kind, and [Trammell] had come across a non-functional example for just $20. It was time to bring this relic screaming into the modern age.
The motherboard was toast, so [Trammell] decided to wire up a Teensy++ directly to the Hitachi HD44102 display driver chips. Being an older LCD, the display needed a negative bias voltage, so a few diodes, capacitors and a PWM line stepped in to create a charge pump. There was no character generator on board, so the heavy lifting is all handled by the Teensy itself. The keyboard was a simple enough matrix design, so that was wired straight up.
[Trammell]’s work with this iteration got as far as acting as a USB serial terminal, and there was some work done on VT100 emulation. However, according to Twitter, the next stage involves an iCE40 FPGA and some music with which we’re altogether too familiar.
[Trammell] owns a working Model 100, too – employed in some modem experiments, no less.
Hackaday Superconference is just a week away (precious few tickets remain), a celebration of all things Hackaday, which naturally includes creative projects making the most of their hardware. Every attendee gets a platform for hacking in the form of the conference badge.
To make the most of your badge hacking fun, plan ahead so you will have the extra components and the tools you need. At the most basic, bring along a serial to USB cable and a PIC programmer. These are common and if you don’t own them, ask around and you will likely be able to borrow them. Now is also the time to put in a parts order for any components you want to use but don’t have on hand!
The badge is hackable without any extras, but it’s designed for adding hardware and hacking the firmware. We’re excited to see what you can do with it. We gave an overview of this retro themed pocket computer a few days ago, today we’re inviting you to exploit its potential for your hardware hacks.
Continue reading “Supercon Badge Hardware Hacking: Here’s What to Bring”
It hangs around your neck, comes with the cost of admission, and would blow away a desktop computer from the 1980’s. This is the Hackaday Superconference badge and you can get your hands on one for the price of admission to the ultimate hardware conference.
Everyone through the door gets one of these badges featuring a 320 x 240 color display, a full qwerty keyboard, and limitless hacking potential! The stock firmware runs a BASIC interpreter, the CP/M operating system, and includes games and Easter Eggs. It’s a giant playground, and we want to see what you can do with this custom hardware during the three days of Supercon. Get your ticket now, then join me after the break for a demo video and plenty more info.
Continue reading “The Supercon Badge is a Freakin’ Computer”
If you were lucky enough to own one of the crop of 1980s 8-bit computers, did you ever pause to consider how its graphics worked? Maybe the really expensive ones had dedicated CRT controller subsystems akin to the graphics cards you’d have found on a PC a few years later, but most of the affordable models would have stopped what they were doing every TV line interval period to allow access to their memory for their graphical output to be created.
The RC2014 retrocomputer dodges all this, by using a serial port as an interface and expecting your serial terminal to handle the screen. But what if it could produce its graphics directly as the machines of old did? [Rob Dobson] set out to achieve this, and not only did he succeed but he also found a way to directly emulate some classic machines along the way.
His RC2014 card which he calls the Bus Raider started as an attempt to use a Raspberry Pi to commandeer the RC2014 memory and read it via its GPIO lines, interpreting the graphics for its own screen. But even with bare metal Pi programming he couldn’t achieve the complex timing required for that, so he took an alternative approach. He ended up with an ESP32 that emulates a custom part of the RC2014 memory map and generates a display from there. Having created a custom memory map and hardware emulator for his RC2014, he then had the revelation that he could emulate any memory map, and thus he could make the retrocomputer perform natively as though it were any of a selection of classic micros. So far as well as a straight serial terminal he has a Sinclair ZX Spectrum and a Radio Shack TRS-80 running, as well as his own custom Z80 environment. And since the ESP32 also has WiFi, he can even connect to it through that medium.
Retrocomputers are something in which you might think that everything possible would already have been done, but projects like this one never cease to amaze us with their ingenuity. If you’d like to read more about the RC2014, we reviewed an earlier model back in 2016.
One of the outliers in the home computer wars of the early 1980s was the Texas Instruments TI99/4A. It may not have had the games library of its rivals and its TMS9900 processor may not have set the world on fire with its registers-in-RAM architecture, but its range of support chips included one whose derivatives would go on to delight subsequent generations. If you had an MSX or one of the 8 or 16-bit Sega consoles, the TMS9918A graphics chip provided the architecture that sat behind Sonic in his adventures.
A few decades later, there is still significant interest in this classic chip. [J.B. Langston] has an RC2014 retrocomputer, and wishing to play MSX demos upon it, has created a TMS9918A-based graphics card for the RC2014 bus. The success of the board hinges upon a circuit showing how to interface the 9918A to SRAM, and since it is mapped to the same ports as its MSX equivalent it should in theory be compatible with Z80 demos written for that platform. He’s already achieved some success with that aim, as can be demonstrated by the video we’ve placed below the break of the Bold MSX demo running on an RC2014.
The RC2014 has gained a significant following in the retrocomputer scene, and has appeared here many times. We reviewed an early model in 2016. Surprisingly though the TMS9918A has only appeared here once, as part of a homebrew 6809-based system.
Continue reading “There’s RC2014 Life In The TMS9918A Display Chip Yet”