M7264 Troubleshooting

He did mention that he had the console card in the slot next to the CPU, which I think is what you're referring to - but it shouldn't matter for ODT, which doesn't use interrupts, only programmed I/O. A QBUS system will work fine without continuity of grant (interrupt, DMA) lines to boards which only respond to DATI/DATO (memory, non-interrupt I/O, etc). Just for grins, I took my -11/03, and plugged the console card in a bunch of slots down, leaving several empty slots between it and the CPU, and it worked 'fine': ODT was fine, and it would run "BR ." programs fine, too. So unless there's actually a break in one of the 'broadcast' bus lines (e.g. BDALxx, etc) on that backplane, between the CPU slot, and the slot the console card is in, or something like that... I suppose it would be worth while checking BDALn, BSYNC and BDIN _on the console card_ (I'm not sure where he was looking at them, before) just to rule out the broken bus line possibility. One thing that's bugging me, though; he said "BDAL3-13 .. are all active and jump around in some manner". But for the ODT microcode loop trying to read the console CSR, i.e. 0177560, BDAL7 (0200) and BDAL3 (010) should be 0, i.e. un-asserted. So why are they jumping around too? Is this somehow related to the odd behaviour I was seeing on my machine with no console card, where the BDAL line was behaving in a way I couldn't understand? I'm going to look into that more, to try and understand what I'm seeing there, but it won't be today, which is 'crane day'! Noel