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Opsss... Pins count exceeds the limit

07/17/2009

Today I made a quick approximate count of all control lines needed and it gave me about 65 which is more than the 57 currently available in the C-BUS.

So far the CPU Backplane layout, internal buses, distribution of resources among cards and similar details are well defined, so I can have much better idea of how the CPU will be and how many control lines it will need at the end. The only problem is with my pick of 96-pin connectors for the Backplane.

Actually, the problem is caused by the need of a Control Bus (C-BUS) consuming all control lines so all control pins at once for all controller cards. The need for a bus comes in turn from the existence of more that one IDS card controlling same control lines.

CONCLUSION: I have no choice but replacing the 96-pin connector with a big one. I have to examine this later with more detail, but the solution seems to be in to keep using 96-pin connectors (DIN 41612 Type C) for Data Slots but for Control Slots, use 160-pins connectors (DIN 42612 Type C Extended) instead.

Since nothing have been built yet, that is not big deal except for the cost increase.


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