Amstrad on an FPGA

If you are from the United States and of a certain age, it is very likely you owned some form of Commodore computer. Outside the US, that same demographic was likely to own an Amstrad. The Z80-based computers were well known for game playing. [Freemac] implemented a working Amstrad CPC6128 using a Xilinx FPGA on a NEXYS2 demo board.

The wiki posting is a bit long, but it covers how to duplicate the feat, and also gives technical details about the design. It also outlines the development process used ranging from starting with a simple Z80 emulation and moving on to more sophisticated attempts. You can see a video of the device below.

Computers of that era often made compromises to save money and work around limited horsepower. For example, the Sinclair computer famously blinked its video when you were typing because the CPU couldn’t drive the display and read the keyboard at the same time. The Amstrad restricted CPU access to memory to avoid conflict with the video hardware, so the 4 MHz CPU was effectively throttled to just over 3 MHz. Exploring these old architectures can show you a different way of thinking compared to the modern web browser eating up dozens or hundreds of megabytes of memory.

We’ve seen Amstrad clones before. We’ve also seen the unholy union of a real Amstrad and an iPod Shuffle where the iPod stood in for a data cassette. Wonder if the FPGA simulator can read tapes?

Filed under: classic hacks, FPGA