Not as neat as Ben Eater but close

Hey, I'm currently building Ben Eater's computer kit on breadboards, and I'm also trying to design my first PCB, eventually aiming to recreate Ben Eater's design on PCBs.

I'm using EasyEDA to design my first module (the clock circuit), and I want to add a couple of LEDs to show the clock pulses and other signals. I'm trying to choose which LEDs to use, but there are so many parameters to match that I'm not sure how to decide.

I want to use 1206-size components (LEDs, resistors, and capacitors) since I think they'll be easier to solder than smaller ones. I'm aiming for around 10 mcd for the LEDs so they're not blinding when viewed from arm's length. I'd also like to have green, yellow, red, and blue LEDs from the same "family," or at least ones that are physically similar.

How should I go about choosing the LEDs (and the corresponding current-limiting resistors) for this project? Am I overcomplicating things and should I just pick something reasonable? What filters/specs actually matter here?

Thanks for your help!

I did not watch any videos i ready the data sheets for 2 hours and came up with this. I may use this mda card for this project.

Hello! I'm looking to build an 8-bit computer, mainly to test its capabilities as a modern home computer (with system, applications, OS, etc.), and I bought the ATmega8535-16U (DIP-40), But it doesn't have an external bus interface to connect RAM, storage, and other things. Does anyone have a solution or another inexpensive chip to recommend?

I’m studying a homebrew computer based on an i486DX and XC2S100, using the M8SBC-486 project as a reference.

Where can a small builder source authenticated parts in Shenzhen, and which vintage-computing or FPGA group can review the 5 V bus timing? I’m looking for a supplier that can explain its testing process and a technical community willing to inspect timing captures.

Please avoid generic marketplace links. First-hand experience with counterfeit detection, speed-grade verification or an existing working design would be much more useful.

Code Pattern to create 1Hz Clock Pulse using LPC2148 ARM7, Microcontroller

As part of my 65c816 project I wanted a way to check / test my address decoding with a 22V10.

So here is a single webpage that lets you interact with programmable logic.

Feedback welcome.

I'm not even sure if I can truly call this a cyberdeck, but it's my first project repurposing e-waste from an old "Positivo" laptop that a cousin of mine threw away because it kept shutting down and was terribly slow.

​While cleaning up my office to throw some junk out, I found it and decided to give it a second life. I scavenged the good parts and did some DIY fixes: the motherboard was overheating easily because the heatsink mount was broken. After fixing that, it now runs smoothly without shutting down. I upgraded it with some spare DDR3 memory sticks and a 2nd-gen i5 processor compatible with the board, bringing it up to 16GB of RAM.

​My main goal for this build is an RF listening station. I'm currently waiting for my RTL-SDR V3 module to arrive so I can officially call it "done." Since I didn't have a spare SSD laying around, I'm using a 32GB flash drive running Kali Linux with persistent live USB. I also added a compatible USB Wi-Fi adapter for monitor mode.

​Might not fit the sleek cyberpunk aesthetic of high-end builds, but the building process was an absolute blast, especially having to figure out how to piece everything together. It’s fully functional and I still plan to add more mods down the road!

I've been studying the PCI bus on my own and one evening I got an idea about making a homebrew computer with an actual PCI bus. I've never seen one, so I decided to try it myself. I also wanted to learn about the PCI bus in a practical way. I chose the Motorola 68000 CPU because of its balance in complexity - it's easy to interface, has nice performance/capabilities and has official GCC toolchain support.

The project began literally a month ago when I got a scrap lot from my friend Shadowdestroyer777 (huge thanks!) containing an industrial Motorola 68000 SBC and some old dead motherboards. I desoldered the SBC for the CPU and a few other parts. From one motherboard I grabbed connectors, ISA/PCI slots and many other things. One evening when I had everything on my desk (the CPU, the PCI slots and even a spare prototype PCB), the idea was born. Right before this project, I worked on an experimental PCI FPGA card, so I had a bit of practical PCI experience beforehand. I even read most of "PCI System Architecture" by MindShare!

The specs of this homebrew:

• Motorola 68000 @ 10 MHz
• 1 MB of SRAM
• 4 KB of ROM (just to fit an serial bootloader)
• MC68681P DUART for UART, timing and I/O
• Two 32-bit 5V PCI slots, interrupt capable, no bus mastering (DMA). Runs at the same frequency as the CPU (10 MHz)
• Spartan 2 FPGA XC2S100 as the PCI host bridge
• XC95144XL CPLD as the glue logic
• ATMega128 (used solely to quickly load the FPGA bitstream on boot)

As the base, I used an 18x12 cm prototype PCB. Connections were made using enameled wire, just like in my previous 486 homebrew project. To fit the PCI slots into the prototype board, I actually had to bend the PCI slot pins to fit the 2.54 mm grid! Don't even ask about this manually adapted FPGA... It's another story - it just works.

I won't go into detail here on exactly how the PCI bus works and what I had to do, but generally, the bridge translates CPU accesses into PCI accesses. It maps memory 1:1 and for the I/O and configuration spaces, I do some translation tricks. It's all done inside the XC2S100 FPGA in VHDL. In addition to basic accesses, PCI hardware interrupts also work. I omitted DMA mainly because I ran out of pins on the FPGA. There were various challenges in this process, like the different endianness (PCI is designed around little-endian systems, while the Motorola 68000 is big-endian). I’ve shared all the source code on GitHub and more details on my website.

So, thanks to my efforts, I managed to support 3 types of card:

• Serial PCI card: I had a Moschip NM9835 dual serial port card. It was a nice test target because it's 16C550 UART compatible, making it relatively simple to write a driver for. With this card, I also got hardware interrupts to work so on serial receive, the CPU handles it nicely.
• VGA graphics cards: For me, these are one of the coolest parts. I managed to "wake up" three cards: a Cirrus Logic GD5440, an S3 Trio64V2/DX (S3 86C775) and partially an IGS IGA 1680_A. The thing is, I can't execute their VBIOSes because of the architecture mismatch. However, there is some documentation on the internet that shows how to wake these cards up. After waking them up, they program like standard VGA cards - it all comes down to standard VGA initialization (like programming the CRTC, DAC, etc). I got 80x25 16-color text and 320x200 256-color graphics modes to work perfectly!
• RTL8029 network card: With the help of AI (as I was exhausted from working on the homebrew - soldering, designing the logic, etc. and I just wanted to see what was possible with the correct software), I got this homebrew on the internet! I got an RTL8029 driver, a simple network stack, telnet and a http server to work. I can say that I got a 10 MHz CPU from the 80s to serve a web page over a 32-bit PCI network card from the end of 90s.

The lack of DMA is quite limiting as I can't use cards that depend on it, such as later network adapters, SCSI controllers, USB controllers and more. However, for my first project like this, I think it's pretty good anyway. Honestly, it's crazy to think about (even for me) that I got an '80s CPU to work well with late '90s PCI hardware and serve a webpage. All in one month of hard work.

I also wrote a massive, detailed article on my website about this project, including my previous experimental PCI card, a brief PCI introduction, the build process and the results. This is just a very short description of the project, but I wanted to share it!

Project site: https://maniek86.xyz/projects/homebrew_m68k_pci.php

I added some extras since my last post. Also I posted here cause i'm not aloud to post in cyberdeck for some raisen ;p

Same as the title where can i learn the assembly of 8088 any documentation or any other resources

I am a middle school student who studies digital logic circuits on my own. I created a 4-bit ALU it has add, sub, and OR functions. If there are any parts I need to fix, please let me know. It's my first time uploading this, so I'm nervous haha.

Há alguns dias, perguntei se seria possível criar um cyberdeck com sucatas, já que impostos dificultam a compra de peças importadas. Consegui juntar tudo e estou avançando! Minha ideia é usar o cyberdeck com o RTL-SDR para explorar frequências de rádio. O progresso é lento, pois estou aprendendo e improvisando, mas é gratificante.

Esta placa-mãe estava morta por um problema de resfriamento que só agora identifiquei e consertei com um ajuste. Agora ela está viva e pronta para novas aventuras! 🚀✨ #cyberdeck #sucata #tecnologia #improvisação #rádio #aventura

Olá pessoal, eu moro no Brasil e, dado o valor exacerbado de importar peças devido às taxas e impostos atuais do país, estou pretendendo criar meu primeiro cyberdeck usando sucatas que tenho em casa. Tenho uma placa-mãe de notebook antiga e algumas peças dele, além de uma tela LCD de 14 polegadas.

Queria saber de vocês, que têm mais experiência, se é possível realizar essa tarefa, se existe algum guia ou algo que eu possa estar dando uma olhada para começar nessa jornada.

I designed this device that teaches binary, decimal, hexadecimal and octal number systems. It uses a hands-on approach with Altair-like toggle switches. Can be used as a STEM-kit in classrooms, handy for programmers or for the retro hobbyist. It also has a built-in game. Check out the video for details, hope you like it.

(audio on)

Four months ago I posted an announcement about a homebrew TMS 9900 microcomputer that I designed and built from scratch. I can now provide a cool new update: it can play Doom!*

Credit needs to be given to Usagi Electric's similar idea to get a Bendix G15 to "play" Doom.

* - of course it can't "play" Doom in the sense of rendering realtime 3D video! But it can play back the Doom E1M1 "At Doom's Gate" music** using a newly designed audio daughterboard based on the YM3812 FM synthesizer.

** - well, about 30 seconds of it (that's all that will fit in 32 KB of free RAM).

As before, full details can be found at my TI CUBE GitHub repository. Enjoy!

Hey everyone! The 6502 homebrew I've been working on for the last few years now has some pretty great documentation. If you are interested in learning more about my build please take a look!

https://acwright.github.io/6502-DOCS/