Messages in this thread | | | Date | Fri, 22 Jan 1999 20:01:08 -0500 (EST) | From | "Richard B. Johnson" <> | Subject | Re: Setting terminal baud-rate. |
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On Fri, 22 Jan 1999, Theodore Y. Ts'o wrote:
> Date: Fri, 22 Jan 1999 10:12:57 -0500 (EST) > From: "Richard B. Johnson" <root@chaos.analogic.com> > > Using version 2.1.131, I cannot set the baud rate of a terminal > to a speed higher than 38400 baud without cheating and using the > `setserial spd_hi` function. This function now results in a > warning message that it has been deprecated.
[SNIPPED termbits.h]
> What version of libc do you have on your machine, and what application > and what version are you using to set the speed? Furthermore, how are > you measuring the speed?
I am using a fairly recent version of glibc. I'm directly making an ioctl(TCSETS, &struct_termios) with the above shown parameters set.
There are no errors. A connected modem works fine. However, this is a long-used call-back program which runs fine at speeds at and below 38400. However when I set the speed to higher values, I noted that the modem would only connect at 1200 baud!
Therefore I got out my scope and timed it. (cat /dev/zero /dev/modem). I measured the time between start-bits (zeros are only start-bits). Assuming 10-bits/baud (1 stop, 1 start, and 8 data), the speeds are as shown. Everything works fine if I use 38400 and set the SPD flag with setserial.
Cheers, Dick Johnson ***** FILE SYSTEM WAS MODIFIED ***** Penguin : Linux version 2.1.131 on an i686 machine (400.59 BogoMips). Warning : It's hard to remain at the trailing edge of technology. Wisdom : It's not a Y2K problem. It's a Y2Day problem.
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