Messages in this thread | | | Date | Sat, 26 Aug 2006 20:37:52 +0100 | From | Ian Stirling <> | Subject | Re: Serial custom speed deprecated? |
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linux@horizon.com wrote: >> Or we could just add a standardised extra set of speed ioctls, but then >> we need to decide what occurs if I set the speed and then issue a >> termios call - does it override or not. > <snip> > Alternatively, you could observe that asynchronous communications only > requires agreement withing 5% between sender and receiver, so specifying > a baud rate to much better than 1% is not too important.
To nitpick. For a 10 bit long word, if the receiver syncs to within 1/8th of the middle of a bit-time at the start, you've got 2/8th of a bit-time of disagreement possible, before you are likely to get errors, especially on limited slew-rate signals. (more modern chips will likely sample faster) Or 3/80, or 2.5%. If the other side has made a similar calculation, then you should only really rely on 1%. 5% is the best possible case - that will in most circumstances cause errors. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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