What is it?

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.

ISA gold fingers for greater signal reliability and board durability.

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.

Why did you make it?

This project is the work of TubeTimeUS. I decided to build myself a unit and had to order 5 PCBs. I did it to study the behavior to replicate the functionality to other personal projects with FPGAs, now I no longer need it and I will sell the original units until the stock is finished.

Own features

As can be seen, it does not have the original SPI flash chip, which will have to be bought and soldered if desired. In exchange, I built a small PCB with prototype board, to add the SPI flash WinBond W25Q16BV that I had. It works perfectly with this memory as can be seen in the pictures.

Options

I offer a fully assembled unit and the others as bare boards. It is an extremely complex piece to assemble, due to the amount of very fine pitch SMD components, it is something that must be taken into account.