I got excited when I saw the title, then checked the URL and it is a software simulation / game of building a computer. I'm not denying this can be interesting, but I've been thinking for a while to get my hands dirty with hardware as a side project. (I'm a software eng by profession). I haven't really done a lot of research on this yet, but does anyone have any recommended guides/books/tutorials on how to get started designing and building my own computer? (extra points it it's a mobile/embedded computer)
Super educational, but if you want to get into more embedded hardware hacking, I would say that building a homemade computer like he does is probably not a super exciting place to start. I'd recommend picking up some Teensy 4.0 microcontrollers and build some small hardware projects with the microcontroller before diving into lower-level circuitry.
Check out Ben Eater on YT. He has a series where he builds an 8 bit CPU from components. And another where he builds a 6502 based computer from scratch. He sells kits to follow along, and explains everything along the way
I would recommended just using the Nand2Tetris book Elements of Computing Systems and implement the computer on an FPGA. I went through the course using the original project’s simulation tools, and I am now circling back and implementing the Hack CPU on a Xilinx FPGA using VHDL.
It has a USB host port for a keyboard and VGA out for the display. The jury is still out as to whether I can build the entire CPU using nand gates, including the ROM and RAM memory. Doing so will use a lot of the FPGA's resources from calculations I've seen. If that's not possible for the memory, then I plan on using the block RAM that's included on the Xilinx board, but for everything else I plan on following the book's design as close as possible. So far, I am in chapters 1-3 simply porting my solutions in the course's HDL to VHDL, which is relatively straightforward so far. I'm taking my time to make sure I'm doing things "professionally", as I'd like to learn the Xilinx toolchain in my professional work at some point. My experience with FPGAs has been implementing them with LabVIEW, which actually makes learning VHDL somewhat mechanical although a bit frustrating. (If I had an FPGA big enough that's targetable via LabVIEW, I could probably build and test the computer in a day or two aside from the VGA and keyboard.) The combinatorial gates are done now, and I've implemented a DFF and am building things from there. So now I'm learning about clocking and such with VHDL. The most troublesome part I anticipate is what to do about the ROM and RAM memory and the display and keyboard. I'd also like to update the CPU where I can interactively download new code to the CPU from a PC using the assembler and software stack I'm building, which is in F#.
I have several books I am using as reference:
- VHDL By Example by Blaine C. Readler (great first intro to VHDL)
- Digital Design Using Digilent FPGA Boards: VHDL/Vivado Edition by Haskell and Hanna
- Effective Coding with VHDL: Principles and Best Practices by Ricardo Jasinski (I'm using this to sort through the various ways to do things in VHDL and have best practices in my code.)
- VHDL for Logic Synthesis by Andrew Rushton
- FPGA Prototyping by VHDL Examples: Xilinx MicroBlaze MCS SoC by Pong Chu
Also James Sharman's channel[1]. He has built an 8-bit, pipelined, computer from scratch. He works at the level of TTL chips. Sharman is good at explaining what he's doing, but does not go down to the very detailed level of bit-by-bit explanation of Ben Eater.
The first question you'll need to answer is if you want to build a computer from discrete gates, or if you'd rather glue large existing IP blocks together.
In the former approach, you won't get anything in a mobile form factor, as your computer would simply be too big. But you might learn more than in the latter approach.
