Date: Sun, 30 Nov 1997 13:20:04 -0800 From: John-Mark Gurney <gurney_j@efn.org> To: John Kelly <jak@cetlink.net> Cc: hackers@freebsd.org Subject: Re: 650 UART, SIO driver, 8259 PIC Message-ID: <19971130132004.41489@hydrogen.nike.efn.org> In-Reply-To: <3481e273.28365467@mail.cetlink.net>; from John Kelly on Sun, Nov 30, 1997 at 10:13:42PM %2B0000 References: <199711301019.VAA09201@godzilla.zeta.org.au> <19971130030719.29570@hydrogen.nike.efn.org> <3484c18f.19943322@mail.cetlink.net> <19971130124508.58609@hydrogen.nike.efn.org> <3481e273.28365467@mail.cetlink.net>
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John Kelly scribbled this message on Nov 30: > On Sun, 30 Nov 1997 12:45:08 -0800, John-Mark Gurney > <gurney_j@efn.org> wrote: > > >actually, the document only gives examples that have four ports per > >interrupt sharing "group"... and this is the case for AST/4 boards too.. > >but there is a special option that allows you to put two AST/4 boards > >on the same interrupt, and this is then the sharred or common irq > > Without some extra wires running between the two boards I don't know > how they can share an IRQ line. Can you explain how they implement > that , hardware wise? sorry, I don't have the boards readily avaliable (they are in my term server that provides inet connection, which is under a speaker, in a corner of my room :) )... plus, about the best I could do is give you some part numbers off the board, and then you would have to tell me which traces to trace... the boards that I'm using are ValuePort V4... they are made by Computone if that would help any... they do have a web site, and their cards included SCO drivers... > >yes, but the thing is that when you have two boards on the same interrupt, > >you actually have to poll BOTH status registers of each board to find > >out what interrupts to serve > > Makes sense ... but two boards trying to talk on the same IRQ line, > without extra wires, makes no sense to me. I think the key is the shared interrupt clear register... but as I said, I am not a low level hardware person... -- John-Mark Gurney Modem/FAX: +1 541 683 6954 Cu Networking Live in Peace, destroy Micro$oft, support free software, run FreeBSD
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