PC Engine dev forum

extended! Version 2.0.



Writing to $xxx0-$xxxF in either bank 0 or 1 selects a 512k segment to be mapped into the upper 512k of the lower 1megabyte memory range. I split the 64megabit memory range across two chips since my programmer only handles up to 40 pin chips Plus, I doubt I could find a 64Mx8bit compatible rom.

Street Fighter 2 uses $xxx0-$xxx3 of Bank 0, so it should work fine with that rom. /Y0 and /Y1 of the '139 go to /CS of the lower 512k separate rom.

That's cool!
By the way, what programmer are you using? Do you have some photos of the board ?

I have the Batronix 40pin usb programmer. Their cheapest model ($150). No photos. I extended the Turborom board. I still need to purchase the parts to build the mapper.