Date: Tue, 19 Nov 1996 15:47:13 +1100 (EST) From: "David L. Nugent" <davidn@blaze.net.au> To: Adam David <adam@veda.is> Cc: hackers@freebsd.org Subject: Re: split speed sio port? Message-ID: <Pine.LNX.3.95.961119153924.562A-100000@server.blaze.net.au> In-Reply-To: <199611190117.BAA02796@veda.is>
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On Tue, 19 Nov 1996, Adam David wrote: > Is it possible with the sio driver to set a serial port to receive at > 38,4 kb/s and transmit at 115,2 kb/s simultaneously? No. At least, not with a standard PC UART (8250 family). > This is n would this be achieved? You need different hardware. The Intel 82510 *may* be able to support it since it has independant transmit and receive clocks, but since I've never tried, I couldn't guarantee it. Normally the 82510 runs in 8250/16450 compatible mode, so this feature (programmable clocks) is normally disabled. I believe that the intention of the clocks weren't so much to support split baud rates, but to provide for psuedo synchronous support (not that I'm aware of anyone using it, but hey - the theory is good! :-)). Otherwise, the chip pretty much pales against the NS16550AFN with only 4 byte FIFOs, despite the other useless but original features. I doubt that FreeBSD's sio driver would support these 82510-specific features, however. Perhaps there are some third-party sio boards which do much the same sort of thing, but I've not come across any. > As a last resort, I could crosswire 2 ports into a single > serial-port connector, but how is it done using only the one port? Hmm. Good luck. :-) Just of interest, why on earth would you want to do this? Regards, David
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