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Marinchip Systems--- 64K Dynamic RAM Board

This is an extremely rare board today. It was the only RAM board Marinchip manufactured.

64K Dram Board

The M9900 64K RAM board was a high speed random access read/write memory board designed expressly for use with the M9900 CPU. It uses industry-standard 16K dynamic RAM circuits to achieve its goals of high speed, reliability, low cost, and minimal power consumption. The 64K RAM board operated with the M9900 CPU at either 2 Mhz or 3 Mhz, with fully transparent refresh which guaranteed reliable data storage without  imposing a speed penalty on  the CPU.   The M9900 64K RAM took advantage of the M9900 CPU's 16 bit data transfer mode. This mode permited the CPU to transfer data on a word by word basis rather than the normal 8 bit byte transfers used by some other S-1OO memories. Use of a 16 bit transfer and the elimination of redundant bus cycles allow memory transfers to be completed in one third the time when the M9900 64K board is being accessed, as compared with conventional S-100 memories. This results in an overall doubling of system performance when the M9900 64K board replaces regular S-100 memories.  

The M9900 64K RAM features programmabe memory management hardware. Pages of memory on the board could be enabled and disabled in 4K byte increments. The initial configuration of the board is set bv switches on the board, and the memory map may be changed at any time by software. When used in conjunction with the Marinchip Multi-User Network Operating System (NOS/MT), this allows system memory configurations as  large as  16 megabytes.

The manual for this board can be obtained here.

Marinchip  S-100 Boards
TMS9900    64KDRAM


This page was last modified on 10/25/2013