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The Graphics Gremlin - a Retro ISA Video Card

The Graphics Gremlin is an FPGA-based ISA video card specifically designed to emulate certain old video standards. This initial release emulates the original IBM PC monochrome graphics adapter (MDA) as well as the original IBM color graphics adapter (CGA). Since the logic is defined by the bitstream loaded into the FPGA, new emulations may be available in the future to support other video standards.

But why emulate an old video card when they are still fairly easy to find online? Cards aren’t hard to find, but monitors that can sync to the unusual frequencies used by MDA (18KHz) and CGA (15KHz) are much harder to find, and these frequencies are rarely supported by modern LCD monitors or video capture hardware.

For both MDA and CGA, the Graphics Gremlin has a VGA port that can deliver video running at standard (31KHz) frequencies that are well supported by LCD monitors, VGA-to-HDMI converters, and USB capture devices.

Here are the design files. The BOM includes Mouser Electronics parts numbers for everything except for the 0.1” headers which are typically cut to length anyway.”

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