Amethyst - Homebrew 8-Bit Computer

8-Bit computers seem to be all the rage. There are plenty of kits on the market that allow you to build your own Z80 based retro computer but Matt Sarnoff decided to give it a go at building his own using a few more modern components.

Amethyst: Built Using An ATmega1284 Microcontroller

In the '70s and '80s, a project like this would have almost certainly used a MOS 6502 or a Z80 processor and require a whole heap of other chips and discrete components. The Amethyst only uses 6 ICs to make it tick: an ATmega1284 microcontroller, an FT320X UART–FTDI USB bridge, a 74HC166 parallel-serial interface and two 74HC157 multiplexers. All wrapped in a elegant custom laser cut wood case.

It also features a composite video output with both high-colour and high-resolution modes that can produce monochrome bitmap graphics at 640x200 pixels, and 256-colour, 16-colour, and 4-bit bitmap graphics at 160x200 pixels. It can also get 40x25 colour characters or 80x25 monochrome characters in text mode.

It also comes with mono audio via PWM, and 4 SPI based expansion ports that allow you to connect things like joysticks, storage devices and other peripherals. It can run BASIC, CP/M or DOS via it's Forth interpreter than runs from EEPROM. Cherry MX Red key switches are used for a 40% layout keyboard and the whole thing is power using a USB Type-B connector that also doubles as serial communications with a PC.

Although it's not a "true" 8-Bit computer, it sure feels and looks like one.

You can find more info on the Amethyst Retro Computer on Matt's GitHub page.

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