I have a board on which core for VME64 bus is implemented and it communicates with other boards on VME64 bus using only 1 connector (P1, 5 rows, 32 pins on each row, total 160 pins) instead of 2 connectors (P1 and P2). I am trying to understand its working in both Bus controller and Remote terminal modes.

I have to modify the connector pinouts to make room for free pins on the P1, 160-pins connector. There is lot of info available about the bus but what I could not find out is the minimum pins required to use VME64 bus?

I can live with only 24-address lines on the bus. But I don't know which other lines I can compromise on to make room for free pins on the P1 connector?

VME64 Connector VME64 Signal names


I don't know what else is in the system and using the bus, but I would look at the bus arbitration lines: e.g. BR3, BG3IN, BG3OUT.

If there are not other bus masters (Processors or DMA controllers) they should be unused.

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  • \$\begingroup\$ Will it be compatible to VME64 bus if we only use 24-address lines which are on the P1 connector? \$\endgroup\$ – alt-rose Jul 26 '19 at 6:02
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    \$\begingroup\$ Depends on what else is plugged into the back-plane. If some card in the system uses the top address bits for decoding, you have a problem. \$\endgroup\$ – Oldfart Jul 26 '19 at 15:03

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