September and the start of October have been a busy time for me but I’ve finally managed at a last to capture to schematic my interpretation of the Uzebox the retro-minimalist homebrew game console. I’ve extended Uze’s design to include a USB and Ethernet interface and also Atari / Commodore 64 / Sega Mega (Genesis) style joysticks / d-pads through a classic 9W D interface.
The USB interface is based on the ubiquitous FDTI FT232 USB to serial UART chip. So far I’ve only connected it to the 644’s serial Rx and Tx and RESET lines but I will investigate if the USB interface can also be used as a AVR programmer as well.
The Ethernet interface is based on WIZnets WIZ810MJ module with a W5100 hardwired TCP/IP Ethernet on a chip. It’s available as a low cost simple drop in module that can be driven either through a traditional address / data bus scheme or through a 4 pin SPI interface. The Wiznet W5100 is used by the Arduino community so AVR drivers already exist to drive the chip.
Finally the Atari/C64/Sega joystick interface is provided by a 4021 parallel to serial chip for each port. The 4021 is used in the SNES controllers so the Uzebox kernel can read them without any changes. The small downside is the Atari/C64/Sega joysticks lack the SNES “Start” or “Select” buttons so I may have to add a couple of switches/buttons to the final design to allow existing games to detect these buttons.
A pdf of the prototype schematic is here. I hope to spend some time on the PCB layout in the coming weeks.