v0.4

Fixes many bugs and adds additional features.

New Features

• DIP Z80 instead of PLCC Z80, for cost reduction;
• Sega Genesis controller support. Also for cost reduction, because: I bet you have a Genesis controller, but not an SMS or SG-1000 controller lying around;
• Debounce circuit on pause button;
• Trim pot for fine tuning TMS9918 input clock

Fixed Bugs

• /JOY_SEL was missing from edge, preventing keyboard from seizing control of the joystick decoding;
• Page-switching logic LOAD signal is now properly inverted when selected;
• Overpour onto expansion edge fixed;
• Missing silkscreens for some parts fixed

v0.3

Soggy v0.3

Many new features added on the base of the v0.2, and some bugs fixed. This was intended to be the first public release, and is recommended for most people.

• /IORD and /IOWR signals (IORQ + WR/RD) synthesized and passed to cartridge port. This prevented the SF-7000 from working, as did an I/O map collision with the keyboard. Both problems are now fixed.
• The full 62256 SRAM is wired up, providing 32K of work RAM to the system. The first 8K are accessible without touching the memory management unit; the second 8K can be switched between four "pages." This should allow Sega BASIC and many other titles relying on SC-3000 functions to work. Previous boards had a 2K mod, matching the SC-3000, but this was not tested.
• An onboard BIOS ROM socket has been added, which runs when a cartridge is not inserted (detected through the "B2" pin on the cartridge slot, which is usually connected to B1 inside cartridges)

Known bugs:

• /JOY_SEL is not connected to the keyboard edge

v0.2

Adds keyboard connector and (hopefully) incorporates all bodges and bug fixes in the v0.1 version.