What is it?

Note: This product is PCB only, and requires additional hardware to function. In addition to the components for the board, you will require an UPduino 3.0 and a suitable VGA or DVI PMOD adapter (Digilent VGA PMOD is recommended). Kits will (hopefully) be available later this year.

Xosera is an FPGA based video adapter designed with the rosco_m68k retro computer in mind (likely adaptable to most any computer with an 8-bit parallel bus).

Inspired in concept only by it's "namesake" the Commander X16's VERA, Xosera is an original open-source video adapter design, built with open-source tools, that is being tailored with features appropriate for a Motorola 68K era retro computer.

Xosera is copyright (c)2020-2021 Xark. See GitHub for license details and documentation. You can follow the project on Hackaday.

This PCB has been custom designed to interface the Xosera FPGA design with the rosco_m68k.

Features

• VGA or HDMI (DVI) output at 640x480@60Hz or 848x480@60Hz (16:9 widescreen 480p)
• Register based interface with auto-increment (as fast as direct mapped)
• 128KB of embedded video RAM (limited by current modest FPGA)
• Character tile based modes with color attribute byte
• 8x16 text with 4-bit foreground/background color attribute per character
• 2-color hi-res bitmap mode
• 16 or 256 color palette out of 4096 colors (12-bit RGB)
• 8KB of dedicated font RAM (or fonts can be in VRAM)
• Smooth horizontal and vertical tile scrolling
• Amiga-inspired Video-Synchronized Co-processor ("Copper")

When used in conjunction with the rosco_m68k v2.x firmware, Xosera is autodetected and works out of the box with a full-featured VT100/ANSI terminal.

Who can build this?

As with all rosco_m68k products, this board is designed to be easy to populate and solder. As usual, our four-layer, all through-hole design means there's nothing tricky on this board and it can be built with generally-available tools.

That said, Xosera is still "cutting-edge" technology for the rosco_m68k, so this is aimed at early-adopters - to get the most out of this you'll be comfortable ordering your own components, exploring the documentation and hacking on the software to take full advantage of the features.

What else do I need?

Please note Because kits are currently not available, you will need a programmer capable of programming both 16V8BQL and 22V10C GALs in order to build this. We recommend the TL866II+.

This product is designed to work with the rosco_m68k Classic v2 and above (sold separately).

In addition to the base PCB and components and soldering gear, we recommend the following:

• Passive components and connectors (See BOM)
• 3x 74HCT245
• 1x ATF16V8BQL
• 1x AT22V10C
• 1x 74LS74
• 1x UPduino 3.0
• 1x Digilent VGA PMOD (Link not allowed by Tindie, please Google)