Northern Connectors Harting DIN 41 612 Connectors - Manual (Page 98)

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ha
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bu
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4
As a typical multiprocessor bus,
VME has to distribute processor
information continuously accord-
ing to the right priorities.
This is done through the well
known daisy-chain lines.
The VME protocol requests 5
daisy-chains on position 1 of
every backplane.
These lines are defined to go
through every daughter card.
Therefore, in case of unloaded
card slots the signal have to be
bridged across the connector.
Bridging variants:
1. The empty card slots may be assembled with
dummy cards, that bridge the daisy-chain
lines.
2. Bridging can be achieved by inserting
5 jumpers on the back plane manually.
3. Bridging by using IC's with internal integration
OR the function may accept automatic daisy-
chaining.
4. The new 5-row connector with switches
allows an automatic switching. In the case of an
unmated daughter card the connector bridges
the signals at positions a21-22, b4-5, b6-7,
b8-9 and b10-11. The switch elements open
automatically when the daughter card is mated,
so that the daughter card accepts the ongoing
signal daisy-chain.
System description with switches
daughtercard
male connector
female connector
OR-gates
IN OUT