So, this is the accelerator.
Pull the CPU and old RAM, add 5 wires to the bottom of the board, plug in the new board. All CPU access to RAM is now at 7.16mhz. All other system activity is at 1.79 mhz. The new board has a 14mhz oscillator, a high-speed SRAM, a 65816, and an ATMEL CPLD (ATF750C).
Most everything works pretty well. Many games and such look and play the same - they are ROMs and do not move the OS into RAM. Some m/l, bit-banging code has problems - SAM sounds like a chipmunk, for example. If you run the OS from RAM, everything gets faster, of course. TBXL screams...
Anticipating questions:
U-Build-It ===> $50?
64K.
600XL, 800XL, 1200XL (with the XL OS mod)
Always ON.
Don't know - have not tried it...
Bob















