Cromemco memory

Oops, I deleted the original so can't reply directly to it :-( I hope someone has better info than me, because although I think I have a 16KZ-K for my Cromemco, the only manuals I can find are for Godbout, Irvine, Integrand, Tuscan, and a few other memory boards -- none of which I have! All I can find is the entry in the 1978 Cromemco Microcomputer Systems catalogue, which says that it offers expandability to 512K bytes with bank select, has fully-transparent dynamic refresh, operates at 4MHz with no wait states, and costs $495 (fully assembled, tested, and burned in, as the 16KZ-W, is $595). "With bank select each memory board may reside in one or more of the 8 possible memory banks. An 8-position DIP switch on the board is used to select each of the banks in which the board resides. "The active bank or banks of memory are selected under software control. Output port 40H is dedicated to this function. Each of the 8 bits of data of output port 40H are used to turn on or off the corresponding bank of memory. A "1" in the corresponding bit position will turn on the memory bank. A "0" will turn it off. All circuitry required to detect the output of 40H is included on the memory card itself. "Bank select provides a convenient method by which to expand system memory space beyond 64K. Bank select also permits the implementation of time-sharing systems with a minimum of software overhead - up to 8 users can use the system simultaneously with each confined to his own bank of memory." This implies the card can be multiply decoded (to appear more than once). I imagine if you want it to appear from 0000H to 0FFFFH, you turn on the switch in position 1, and turn off the rest (unless you want it to appear elsewhere as well). Similarly to appear from 10000H to 1FFFFH, switch position 2. Although, since it's easier to provide a pullup resistor than a pulldown on TTL, likely "switch on" grounds the line and means a "0". Try it and see! -- Pete Peter Turnbull Network Manager University of York