Date: 2006-07-16 12:08:37
On 2006-07-09, at 10:27, Spiro Trikaliotis wrote: > Hello, > > in the German forum C64forum (cf. > http://www.c64forum.de/wbb2/thread.php?threadid=11558 > ), an interesting question came up: The person posting there would > like > to see the following functionality added to OpenCBM: > > He wants a function which gives every device attached to the serial > bus > a unique device number. Ideally, the one nearest to the computer > (or the > farest one, it does not matter) gets the 8, the next one the 9, and so > on. > > He says that he had had a C64 copy program with exactly that > functionality, but he cannot find it anymore. > > All solutions for such a thing require very exact timing measurements, > something which is not possible with the 154x/157x/1581 hardware. Does > anyone here have a good idea how this could be accomplished? [...] > The person posting there already has some ideas: [...] > Disadvantage: The numbers will not be sorted from the nearest to the > farest, but completely random. > > Oh, another idea comes to my mind, similar to the protocol used on the > CAN bus: [...] > Again, the big disadvantage: The numbers will be random, not from > nearest to farest. > > > What do you think? Is there a better approach then the one proposed > there? Since nobody answered this - it seems "no" ;-) I was refraining from answering for some time as I hoped I could somehow be wrong but: if the IEC bus is just a passive, pass-though, whatever we call it - bus, I see no way to distinguish the position of the device on the bus unless we were able to measure over-the-wire signal propagation latency... > Additionally, from where could I get a true random number in the > floppy? Hm, a "true random" you rather get nowhere but even a kind of quasi- random may be tough to get from the floppy. Thinking aloud... maybe feeding some timers with off-the-(magnetic)head readout? Message was sent through the cbm-hackers mailing list
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