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The Amethyst is a retro-styled “home computer” built around an Atmel ATmega1284 microcontroller. It features composite (NTSC) video output with both high-color and high-resolution modes, mono audio output, and a full-travel mechanical keyboard. It includes a full-featured implementation of the powerful Forth programming language, with graphics and sound commands, debugger, and screen editor. A single USB Type-B cable provides 5V power as well as serial communication with a PC. Amethyst is compatible with the Optiboot (Arduino) bootloader, and new firmware may be uploaded to it without a specialized programming device.

Full specifications
ATmega1284 microcontroller (8-bit) running at 14.318 MHz

16KB internal memory (16352 bytes available for applications)

4KB nonvolatile EEPROM memory

Mechanical keyboard with Cherry MX keyswitches

NTSC color and monochrome composite video output:

256-color, 16-color, and 4-color bitmap graphics at resolutions up to 160x200 pixels
Monochrome bitmap graphics at resolutions up to 640x200 pixels
40x25 and 80x25 monochrome text modes
40x25 color text mode
40x25 color tiled graphics modes
Single-channel audio output (pulse wave or PWM)

USB serial communication at speeds up to 57600 baud

Four SPI expansion ports for peripherals, controllers, and storage devices

Only 6 chips (ATmega1284, FT320X, 2x 74HC157, 2x 74HC166)”

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