Messages in this thread |  | | | Subject | Re: serial.c (half duplex support) | | Date | Mon, 01 Nov 1999 15:27:02 +0000 | | From | David Woodhouse <> |
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hps@tanstaafl.de said: > Wouldn't it be easier to put a small microcontroller (say an 8051) on > a board with a reasonable intelligent PCI bridge and implement the > packet transfer in this controller? Then you would just put your > telegram onto the chip, say "hey, send it out" and have no longer > worry about specs?
Also being investigated. Actually, I prefer the idea of switching our fieldbus to ARCnet - which can handle IP traffic as well as the low-level stuff. You can get a chip with an 8051 core and an ARCnet core next to each other, which is quite nice.
> Ok, you can't use your $10 standard PCI serial hardware, but at least > any user could be assured that the right lamp / engine / magnet is > turned on or off.
I fully intend to support 'decent' fast serial ports, running RS485 up to 1.5Mbaud, but I may have to build such boards myself - and if I want widespread testing of my Profibus code, there's no substitute for commodity hardware.
> If this protocol is only really reliable in hardware, why not > implement it in hardware.
It's not that it's not reliable in software - it's just that we might not be able to pass the certification in software - that's a different thing.
With a little care (and hdparm -u) we can get it to be _reliable_ without too much trouble - this is Linux, after all.
---- ---- ---- David Woodhouse David.Woodhouse@mvhi.com Office: (+44) 1223 810302 Project Leader, Process Information Systems Mobile: (+44) 7976 658355 Axiom (Cambridge) Ltd., Swaffham Bulbeck, Cambridge, CB5 0NA, UK. finger dwmw2@ferret.lmh.ox.ac.uk for PGP key.
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