Date: Sat, 22 Oct 2005 22:30:37 +0930 From: "Daniel O'Connor" <doconnor@gsoft.com.au> To: ticso@cicely.de Cc: Frank Behrens <frank@pinky.sax.de>, freebsd-hackers@freebsd.org Subject: Re: How disable attachment of sio(4) driver to device? Message-ID: <200510222230.39376.doconnor@gsoft.com.au> In-Reply-To: <20051022121818.GR31913@cicely12.cicely.de> References: <200510210835.j9L8Zn2P001846@pinky.frank-behrens.de> <200510221601.07346.doconnor@gsoft.com.au> <20051022121818.GR31913@cicely12.cicely.de>
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--nextPart1606071.GO29isFLg7 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Sat, 22 Oct 2005 21:48, Bernd Walter wrote: > That's the big win with 9 bit. > Modbus uses 8 bit so each controller has to actively listen. > The RTU variant uses fixed idle times to mark packet ends, which is > hard to do right in kernel and unreliable to do from userland. > Since I needed multi-OS support and have at least one customer with > many busses the kernel was no option. =46air enough. Your solution sounds very flexible and useful! > Don't know about line discipline abilities, but I remember that some > trustfull persons declared this to be doable. > It is the whole hardware design that won't fit. > As long as timing is not critical and you have legacy serials it is OK. > But many USB uarts don't have native 9 bit support as well, and the > nature of USB is that you really want large FiFos. > This is a dead track IMHO. Yeah, I think the line discipline approach is feasible with legacy hardware= ,=20 but USB makes it difficult to do. > The whole thing is suboptiomal. > Today there are no reasons to not offload the tricky parts into > external devices. Heh, apart from dev time :) > I'd originaly used Atmel Mega8 plus Philips PDIUSBD11 for this. > It was a slow but reliable and cheap combination, but Piliphs stopped > production of the chip. > Today I use Mega64 and PDIUSBD12 for USB and Mega128 with RTL8019AS for > Ethernet, which gives me two UART for use in a single device. > The controller have 9 bit wide FiFos. > If you are already in the 8051 world, you might look at TI TUSB3410. Ahh looks interesting. I have used Atmel a bit to play around with it.. I h= ave=20 some sample 3410's but haven't even assembled the test board I made :-/ =2D-=20 Daniel O'Connor software and network engineer for Genesis Software - http://www.gsoft.com.au "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C --nextPart1606071.GO29isFLg7 Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (FreeBSD) iD8DBQBDWjf35ZPcIHs/zowRAgcqAJkBQ5oPbnDKSfJ1odRtsTmYLnL8QACfd3IT QbrGuCas3huCBoUybB4M0Wg= =uuml -----END PGP SIGNATURE----- --nextPart1606071.GO29isFLg7--
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