[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Bank Select Logic

Good Evening, most knowledgeable list.

I am in the process of building a second S-100 computer.  (My first one is now nearly 35 years old.)  I am hoping to use CPM3 on this new system in banked mode.  I have several 8-bit 64K S-100 memory boards I want to use, but while they all can be configured for 24-bit addressing, my CPU is a Z-80 that won't address anything higher than 64K.  I know CPM3 can be configured for using bank-select logic that takes an I/O port and latches that to the upper 8 address lines, but I cannot find any solid information about how that is done or any particular standards that have been used.  Neither can I find any hardware that actually implements this bank-select function.  If anyone has familiarity with this hardware, the theory behind the function, or can point me in the right direction, I would be very thankful.

Bob Bell