Hi,

I am now plan to made a 1MByte RAM card for my HP48GX, seems I could
not find enough information to build up PCB. I did search hpcalc.org
where only mention about 128kbyte card mostly or I overlook something.

Does anybody direct me where can I find such information, I know there
is some logic IC to switch the port selection, how? please help.

Thanks

Roy