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Cromemco 16K Dynamic RAM Board  
Cromemco almost from the start decided to build their systems with dynamic RAM memory cards. They started with this 16K card. It was produced with minor modifications for many years.

Cromemco 16K RAM  

The card had a bank select feature allowing up to 8 banks to reside in one system. Active banks could be selected in software -- ideal for multiuser systems and CPM3 by outputting the appropriate bit to port 40H.  Each board had an LED indicating when it was active. The board also could handle DMA but did not have its own onboard memory refresh controller. Refresh was done during the 8080 or Z80 M1 cycle.  Not sure it would work in more complex master/slave systems. As with the Vector Graphic boards without an LSI refresh controller special care had to be taken with the POC/RESET lines that the signal times were short (see manual below). The card worked at up to 4MHz with no wait states.
The manual for this board can be obtained here


Other Cromemco S-100 Boards
ZPU  SBC   4KRAM  16K RAM  64KZ RAM  64KZ-II RAM  256KRAM  8KBytesaver  Bytesaver-II  
16KPROM  32K Bytesaver  4FDC   16FDC  64FDC  WDI  WDI-II   STDC   DPU
4PIO   8PIO   TU-ART  D+7A I/O   Dazzler  PRI   GPIB Board   XMU  XXU  Other Boards


This page was last modified on 10/25/2013