There was a time when creating a new IC was a very expensive proposition. While it still isn’t pocket change, custom chips are within reach of sophisticated experimenters and groups. As evidence, look at the Moushik CPU from the SHAKTI group. This is the group’s third successful tapeout and is an open source RISC-V system on chip.
The chip uses a 180 nm process and has 103 I/O pins. The CPU runs around 100 MHz and the system includes an SDRAM controller, analog to digital conversion, and the usual peripherals. The roughly 25 square mm die houses almost 650 thousand gates.
This is the same group that built a home-grown chip based on RISC-V in 2018 and is associated with the Indian Institute of Technology Madras. We aren’t clear if everything you’d need to duplicate the design is in the git repository, but since the project is open source, we presume it is.
If you think about it, radios went from highly-specialized equipment to a near-disposable consumer item. So did calculators and computers. Developing with FPGAs is cheaper and easier every year. At this rate it’s not unreasonable to think It won’t be long before creating a custom chip will be as simple as ordering a PCB — something else that used to be a big hairy deal.
Of course, we see FPGA-based RISC-V often enough. While we admire [Sam Zeloof’s] work, we don’t think he’s packing 650k gates into that size. Not yet, anyway.
The most popular computer ever sold to-date, the Commodore C-64, sold 27 Million units total back in the 1980’s. Little is left to show of those times, the 8-bit “retro” years when a young long-haired self-taught engineer could, through sheer chance and a fair amount of determination, sit down and design a computer from scratch using a mechanical pencil, a pile of data books, and a lot of paper.
My name is Bil Herd and I was that long-haired, self-educated kid who lived and dreamed electronics and, with the passion of youth, found himself designing the Commodore C-128, the last of the 8-bit computers which somehow was able to include many firsts for home computing. The team I worked with had an opportunity to slam out one last 8 bit computer, providing we accepted the fact that whatever we did had to be completed in 5 months… in time for the 1985 Consumer Electronics Show (CES) in Las Vegas.
We (Commodore) could do what no other computer company of the day could easily do; we made our own Integrated Circuits (ICs) and we owned the two powerhouse ICs of the day; the 6502 microprocessor and the VIC Video Display IC. This strength would result in a powerful computer but at a cost; the custom IC’s for the C-128 would not be ready for at least 3 of the 5 months, and in the case of one IC, it would actually be tricked into working in spite of itself.