My first cut on the "new" ver 3 S100 RAM/EPROM board
Make the chip pairs use the SAME configure jumpers
Make both pairs of chips use the SAME pin-out ie; ram or prom in either side, Support RAM on both chip pair.. 28 pin part or larger, this will allow ram or prom to be in lower or higher bank
Remove the jumpers for older and rarely used chips to make the board easy to configure. ie: remove option for chips less that 27C256, or 27C512 (ie: 28pin parts an above)
this will make addressing selection easier..
map address line for RAM using same pins as PROM... ie: no need for matching data sheet, as Ram is not sensitive to address line mix up...
Allow for use of a battery (CR2032) on board to back up RAM as its done on ZetaZ80 with option for external battery option (3 pins... gnd.vbat.gnd) using a DS1210 (allow for two battery sources)
Support for large 39SF040 with a jumper on A18 to select high or low haft of chip, this will allow multi images in prom
Keep small 8 bit boot rom, support 24 and 28 pin devices... allow support of using large chip up to 28C512 with hi/low select of extra address lines... to allow multi images in prom