Amethyst: 8-Bit Home Computer, Powered By An AVR Microcontroller

[@crusaderanimation6967]

when i read "Amethyst: 8-Bit Home Computer," you got my curiosity, but when i read "Powered By An AVR Microcontroller" u got my attention

[@bradscott3165]

FORTH IN ROM. Absolutely badass. I bet it was all kinds of fun writing the forth kernel for that thing.

[@PU7MZD]

Next step is porting DOOM. Amazing project!

[@dmitryhetman1509]

Doom is very heavy for that kind of PC, but NES had DOOM port, so this 8bit beast also capable of it but not sure..

[@dmitryhetman1509]

I mean SNES

[@dmitryhetman1509]

8 bit is not enough to reproduce doom I guess.

[@cbmeeks]

@@dmitryhetman1509 Doom was ported to an expanded 37KiB VIC-20 and runs surprisingly well with audio. Just search for VIC-20 Doom.

[@excitableboy7031]

You cant run doom on everything, most videos about stuff powered by microcontrollers "running" doom is simply taking the input and passing the output, with the processing being done on a host

[@tecnociclista5342]

Amazon to see stuff like this, a single person designing the hardware and doing all the programming...I need to learn a lot :) Kudos!

[@janikarkkainen3904]

Oooh this so cool! I'm kinda in the process of designing my own "8-bit computer", but my current abilities (had no real experience w/ electronics until a month or two a go) have me stumped on memory restraints on ATmega328p (been thinking about either upgrading the AVR to one with more memory, or do either parallel sram with glue logic or OC to >20MHz and dual quad-spi memory). I was going to do color later with just resistor dac to RGB and use composite for sync (SCART is a godsent), but I got intrigued about NTSC artifacting. I know this video is akready 6 mo old, but I really hope you get back to us with an indepth explanation about NTSC Color Artifacts! Thanks for the great video!

[@candidmoe8741]

At first I thought that was a factory made computer. Very well done.

[@hotkeymuc]

14:34 "a typing demonstration of me typing on this keyboard" - Love the Chyrosran22 reference :) (...and the whole rest of the project as well of course!)

[@ricardlupus]

This is so beautifully done, from the circuitry to software to case and keyboard.

[@willofirony]

Great video and even better project. I am often more impressed by the ingenuity employed when the resources are restricted than the general results of higher level programming and ability to treat resources as infinite. Impressed would be quite the understatement for my appreciation for what you have achieved with this project. Awesome!

[@Alex2Buzz]

This is the kind of thing I subscribed for. Very happy to see more computer projects, though I do wish we'd seen the project as it went...

[@freeelectron8261]

Pre-VGA 8 bit - I remember them back in the early 80's. Nice job on the little Amethyst retro box!

[@dirtfriend]

very cool! i'd definitely buy a kit of this if it was available :)

[@alangiles2763]

Me too, FRed, it is a fantastic and good looking piece of work

[@Xoferif]

I'm pretty sure it was Woz that came up with this NTSC colour generation technique. I remember one of his talks where he described being in a sleep-deprived state and staring at a bunch of arcade cabs that were on test at Atari (which had coloured pieces of cellophane pasted over a mono screen) and the idea starting to form in his mind. Anyway, really nice work with the Amethyst!

[@PauloConstantino167]

ye! you can substitute some analogue signals by a digital signal as an approximation.

[@yestertechnet]

Al Alcorn taught Woz the trick, and Woz did what Woz does - optimize it. spectrum.ieee.org/tech-talk/tech-history/silicon-revolution/al-alcorn-creator-of-pong-explains-how-early-home-computers-owe-their-color-to-this-one-cheap-sleazy-trick

[@squirlmy]

I believe that would have been "Breakout!" Its certainly the one game where actual color made little difference. True the ball looked weird going through the "layers" but this only happens when the ball is far away from player interaction with the paddle, so it wasn't too distracting. Such things inspire creativity in code. Likewise the PC's real mode and protected and other memory modes inspired coding tricks.

[@bryede]

The problem with the Apple trick is how dirty it looks without color amplitude control. You get as much artifact as actual color. You gotta hand it to Woz making full-feature computers with off-the-shelf TTL, but it was always going to be a giant compromise compared to an ASIC design.

[@jnharton]

@@bryede You also have to consider that they were trying to control costs too. I'm sure he could have done quite a bit in standdard TTL without an ASIC, but they were trying to make a product not throw a lot of money out the window.

[@dgstephens]

What a wonderful project beautifully executed. I would love to see more about this project - especially how you implemented video. Thank you for sharing it with us.

[@JonMcPhalen]

I'm not a retro computer guy, but I do like the simplicity of that design. Have a look at the Parallax P2 chip -- for those who enjoy building retro computers, it will make life very nice.

[@martin-ot]

So nice compact build, and I really love your design skills. Such a beautiful computer! I really love the design work you have put into it.

[@MattSiegel]

lol, spectacular!! super output, you really pushed that chip to the limit :D (nice hat tip to thomas at the end too, haha)

[@2kBofFun]

Nice, when I got my first 1284 it was just my idea to build a computer around it, but watching this is a good start. I had the crazy idea to connect a SAA5050 for image generation.

[@andrewpalm2103]

I've done a good bit of Mecrisp Stellaris Forth programing on the STM32 series. Forth is great for micros. Back in the 80's I had a Forth cartridge for a VIC 20, too.

[@walnuthills11]

Looking forward to your upcoming Amethyst Forth video!

[@ExperimentIV]

ooh, the one with the spacebar but with the other keycaps would be so nice to play around with. very nice work!

[@Gsus__17]

Please continue with the videos on your computer, I like them a lot and they are very promising. They encourage me to continue with my Arduino Due PC. Good luck, greetings from Spain

[@metatechnologist]

There were/are a couple of other books that were a follow on to the tty typewriter cookbook by Don Lancaster that get into color generation. The Cheap video appeared in 1978. The Apple Il appeared in 1977. Which leads me to think that the idea quite possibly came out of Atari where Wozniak worked iirc. Imo it could have originated from actual color tv circuitry. Sony and RCA had very competent engineers. Reading the technical articles from them is amazing as one realized how brilliant a lot of these guys really were!

[@child_of_god_]

Brings back memories from late 80s Man, time just flies

[@GeneralVanRyberg]

Wow, such a cool project! Not only is the concept super nice, but it also looks very, very impressive.

[@MrMikeHawkey]

I only just stumbled on this. Like many, I'm also playing with the concept of a modern retro computer based around a microcontroller. I'd love to see updates explaining the inards in more detail. Very nice build. Well done.

[@wizdude]

I like the keyboard in the prototype much more. Staggered keys and a spacebar in the expected spot. Great video :-)

[@3vi1J]

Just now stumbled upon this while surfing retro channels. Great project and great design! I must say, I prefer the keyboard on the first prototype unit. Having the keys straight up/down over each other and a space button like the other one would drive me bonkers.

[@benjaminscherrey1124]

Yeah forth!! Looking forward to seeing the details about that. I kinda like the prototype keyboard layout better.

[@gustinian]

Forth rocks! Youngsters are missing out...

[@earlpottinger671]

I never programmed in FORTH, but I remember reading up on it and it need very little to get started (small ROM). I had a SuperPet for work and one thing I wished from that time is that other 8-Bit machines came with the option to program in more than one language. On my Commodores it was only BASIC and Machine Language (6502 and 68000) but I wish Forth, Pascal, APL and others came as standard, imagine how much more early programmer would have learnt.

[@bradscott3165]

@@gustinian To this day I still catch myself saying "Forth" when I'm talking about Python. And I'm a python kinda guy. Forth was the original python.

[@NilsKullberg]

Extremely nice! Very inspiring! Can't wait to see the next episodes of this series.

[@mheermance]

Neat project. I'm looking forward to learning more about how you generated the graphics. Also, go Forth programming language!

[@pu5epx]

Nice move, getting rid of space to make room for numbers. Will think about it in my next 40%.

[@gregclare]

Nice project. It’s probably just me, but for some reason I found it kinda amusing that you’d actually labelled the power indicator LED as “Power Indicator” :)

[@MisterWillX]

This is a beautiful piece of work. Good job!

[@eekee6034]

I love the keyboard... except for the lack of a space bar! XD But no, I could get used to it and love it anyway. :) Cool color output trick, especially to get 256 colors! You're much less guilty of false advertising than Atari. ;) They advertised (and demo'd) 256 colors on-screen at once when the hardware was only capable of 128. It also looks like you can use many colors more freely. "AMSCII" made me grin! 10:03 That first cat pic looked really arty in the Amethyst's palette. I was too busy reading the game screen to listen. Had to rewind twice! XD And Forth; nice! Sweet little machine.

[@TimoBirnschein]

We had AVRs for decades and we have seen lots of cool stuff over the years (like UzeBox for example). But this really blows this out of the park. Thank you so much for sharing! Makes me want to make one :)

[@azizyahaya2174]

nicely done. its surprising how much can be achieved with so little

[@billkillernic]

lack of the spacebar is not the only issue... the keys are also aligned in a normal keyboard e.g Q is not right above A its on an angle above A and so on and so forth.

[@LewisCampbellTech]

Super cool. Was really curious about the forth stuff!

[@gerrytemple5044]

No second part in over a year of Covid-19? I'm really curious to see more mate 👍🏻

[@vitalian1980]

Looks like you have contributed a lot effort into the project. Great work!

[@hrnekbezucha]

Super impressive! I'm really curious about the updates

[@abdelkadernechadi7497]

AWESOME, and speaking of color, I'm now GREEN with envy.

[@RoyAndrews82]

Very Cool. I especially liked the colors part.

[@Pridetoons]

I'll be waiting for your next video on the Amethyst.

[@GeorgeGray43]

Very nice! Love how you packaged it.

[@Aeroman66]

Such an amazing work! Just loved it. I'm currently working on a homebrew too, but using a pic18. It would be nice to exchange some informations Congratulatuons again!

[@ice2642]

Very impressive! Congratulations.

[@anonUK]

Cutting-edge 1981 technology!

[@rivest-oss]

Wow! This is awesome! Did you do all this on your own? That's a lot of pretty hard work. The computer is beautiful!

[@cosmicrdt]

Are you still planning on doing another video? I'd love to hear more about the design.

[@SteveJones172pilot]

Definitely interested to see how the video is generated, and also to see how you implemented that keyboard..

[@olavl8827]

Fantastic project. I'm really curious about the code and schematics. This is going to be inspirational.

[@BrightBlueJim]

Go to the github link - it's all there.

[@dazealex]

Amazing! I want one just to have it in my collection.

[@joet2057]

Subscribed! Waiting for it to be connected to the internet!

[@Manwe_SandS]

8:30 - demo or die! :) Such a cool machine, even equipped with Forth! Wow. Wanna make demos on it!

[@MrCoalmin]

Can you slow down the clock speed? I know I'm weird but I love having to wait - helps me savour the experience.

[@boelkrug]

Hey Matt! I am super-impressed by this build and it is very close to my dream computer. It is amazing and I would really like to have one too. I have seen many different approaches to the feel of 80s computers with all its simply programmability, instant-on features, all fit in the keyboard. Also love the reduced set of keys, as when looking at my 101 key keyboard most of the keys are not used anyways. I am thinking of going a similar approach as you did with mechanical keyboard and all circuitry fit in the keyboard case. What I am currently looking at for using as the main piece is the Teensy 4.1, to have a lot of horsepower, still Arduino compatible though, and have the additional Ethernet PHY and microSD card slot as well as an USB host port. Basically I would replace the ATmega1284 and FT320X with the Teensy 4.1, keep the rest as your build first. Would really like to get in contact and know what your thoughts are on this. I wonder if you can have TinyBasic as one of your startup items. Cheers, Berni

[@bentbilliard]

Wow, that is pretty impressive. Well done!

[@meneeraart4714]

(No picture? O, wel...) Low-tech spacebar add-on: A wooden "hook" suspended by the space-key, and a pivotal foot on the left-most side. _ ______| press anywhere along it's length to pivot (except directly above the pivot-point), and lever down the space-key. Should be an easy project for a GlowForge alumnus ;-) I *love* this bare-bones 8-bit. Fantastic educational project.

[@RogerBarraud]

Nice 1974-style Hi-end case! :-)

[@TroyFletcherKeyboards]

Very interested in your internet serial communication through a raspi. Also would be interested in a kit with a BOM.

[@nosville22]

the Chyrosran reference at the end good stuff

[@unebonnevie]

This is really good, man! I love the ATMEGA1284! I see that your github id is 74hc595! LOL! That's my favorite logic IC!

[@trentjackson4816]

My fav 74HCxxx chip is 74HC945. Problem is that they are like hens teeth to find!

[@2-_]

your website with millitext made me realize the pixels on my screen are backwards, they go BGR on mine instead of RBG

[@temporarilyoffline]

Will this be a solder kit?

[@berndeckenfels]

It's a beautiful piece!

[@thatroom]

run some compression and normalization on your audio, please. i had to hit CC to have any idea of what you're saying

[@viniciusmv7727]

Amazing project. What if you use a second AVR just to generate video and use the extra headroom to have external ram and ROM?

[@ALPHA-555]

This is a really cool project !

[@cyberlord64]

How possible would it be to add a floppy and a 5.5 inch oled module as a monitor like the SSD1322 you see on aliexpress (256x64)? Would the ATmega1284 be able to interact with the floppy drive and drive the screen?

[@kilianhekhuis]

Just found this, nice! Given this is a video from 6 month ago, are we going to see some more vids in the near future?

[@mikloslorinczi227]

Very nice design!

[@rodneyjweltham150]

… somewhere in a drawer I have an original Sinclair 1000 computer. I wonder if at some point you could do a review or a tear apart and rebuild of such a beast…

[@SineN0mine3]

A beautiful machine, great work!

[@send2murph]

Exceptional project! Thanks for sharing.

[@KonradZielinski]

I'm imagining a version with three micro controllers, one acting as a graphics chip, one for sound and the third as a cpu.

[@trentjackson4816]

Problem with that is getting all three micros to talk to each other fast enough.

[@prog4925]

Thanks to the algorithm to recommend me this.

[@lovemadeinjapan]

Can this be tweaked to become a RGB PAL machine? What if you bitbang the video stream and use 3 resistor ladders for D/A? You could have 3-3-2bit RGB out.

[@bjarnenilsson80]

Hmm interresting project, the only question ks, will you regret going for analoge video going forwarspd, analog inputs are dissapering

[@michaellosh1851]

Wow, this is really neat and impressive! I'm amazed that you get that much color quality from the artifact signal effect. Cool keyboard too! I'm a Forth fan from a long ways back, so I'm especially interested in that aspect of the project, but actually I'm eager to hear more about all parts of this project. I hope you post again soon! I've been starting to dabble in making a 16-bit stack processor design in FPGA that could go into a retro-style computer. I have in mind something like "what if Commodore was inspired by Chuck Moore's NOVIX processor (in the same way apple was inspired by the Xerox Alto) before the Amiga came to be?" I haven't gotten very far with it, but beyond the processor, I want the FPGA to also implement video generation. I'm likely to try a variant of VGA, but I really want to see how the color artifact effects are generated in the Amethyst... it seems so elegant.

[@LastofAvari]

Matt: I will show you Forth programming language in the next video. Also Matt: doesn't upload anything for half a year ;)

[@jondoe6608]

make that a year

[@CykPykMyk]

Ten projekt jest nieziemsko kozacki.

[@angelperez7891]

Good god! Really nice little computer!

[@Jalecko]

this just looks so nice

[@AppliedCryogenics]

This is brilliant. I bet if ported to an ATmega2560, you could use the external memory interface add a sizeable chunk of SRAM. Of course, that would blow the whole through-hole aesthetic in a major way, which is probably a show-stopper. I feel like a cheater using an ATmega644 as a 'sound card' in my 6309 system, but at least it sounds good. Had to use latches to interface it to the bus though, because INT0 interrupt latency is just too high.

[@CP200S]

I love Rick Stout+Harley Hahn's Internet Yellow Pages!

[@Applecompuser]

Very cool. Makes me miss my 8 bit Atari.

[@TheWinnieston]

Yeah I'd also buy this as a kit, looks dope

[@jj74qformerlyjailbreak3]

I have a usb1286. I don’t even know what it is. But would like to know more about it. Same size as a RPi. I’m curious to use it. Anyway. Your video has taught me some things about color modes. Thanks for your time teaching and sharing. God Bless.

[@kevinof1978]

Great project!

[@shinmai]

A home computer w/ an ortholinear keeb 💜 (that layout is a bit sketch, though 😅 but I assume that could be hacked into something more comfortable quite easily in software)

[@amnesie6615]

WOW! It is possible to make use of the GPIO-Ports via BASIC? This would be great! For example for our lovly blink-sketch :D

[@tomcombe4813]

Odd question here but what voltage range is the mono audio out?

[@extantpedant1481]

Beautiful!

[@szymonpluta3938]

Hi, i have a question. Possible is maybe extended of RAM memory? 16kB is a bit low even for an 8bit computer...

[@BrightBlueJim]

Unfortunate, about your 6809 project. I'm seeing new projects like Amethyst almost weekly, and they just point out the biggest flaw: Running on a Harvard architecture with the code restricted to FLASH ROM, they - all of them - can only run an interpreted language. This project looks really great, and it looks like you can write the Forth code on it (I'm guessing that, based on the included editor), which is a big plus - it means that once the initial code is loaded, you never really have to connect it to a "real" computer again. I don't know why you stopped development of the 6809 system, but others have said things like, "well, if I wanted [my {Z80 | 6502 | 6809} project] to be a self-contained system, I'd have to include a compiler in it, which is way too big." To those people, I now say, take a look at NAND to Tetris, which goes from designing a CPU from absolute scratch (thus the "NAND"), to being able to compile code for it (running on an emulator) in a JAVA-like compiled language called "Jack". Which can run on the computer itself, which is the "Tetris" end of the chain. www.nand2tetris.org/. What I'm suggesting is that Jack may be a good language to port to ANY small CPU, the compiler for which fits into a very small footprint. But again, this looks great, as an 80s style TV game console, and the 40% keyboard, RJ-12 controller jacks, and "NTSC artifact color" all add to its charm.

[@DancingRain]

With all due respect, please boost the volume on your audio. I have the volume turned all the way up, and I can barely hear you.

[@intel386DX]

I love the wooden case :)

[@ivanski28]

I like your profile photo 😁

[@retrozvoc6189]

Wow. Atmega1284P. I've got one laying untested cuz I don't know where to buy a programming device for it. Can you help me out? Will USBasp help at all? I hope I don"t need to buy expensive programming devices like JTAGICE mkII.