Date: Wed, 11 Dec 1996 11:48:14 -0700 (MST) From: Terry Lambert <terry@lambert.org> To: amir@comtrol.com (Amir Farah) Cc: hackers@freebsd.org Subject: Re: driver problems Message-ID: <199612111848.LAA06756@phaeton.artisoft.com> In-Reply-To: <199612111526.JAA23157@rocket.comtrol.com> from "Amir Farah" at Dec 11, 96 09:26:39 am
next in thread | previous in thread | raw e-mail | index | archive | help
> problem: > > I have a serial port driver which works fine with modems. I can make PPP > connections and all is well. The problem is "cu". The first time I run cu on > a callout port it runs fine. When I quit it drops DTR and exits normally. > Next time I start cu on the same port it just hangs until I either turn off > the modem and turn it back on or remove the port cable from the modem for a > second. Everything then works fine. It starts taking at commands and ~. to > quit. I can enter cu again and it will work. Just that each time I quit I > have to turn off the modem. What remains hanging when the driver closes the > port to cause this problem?? On on-to-off DTR, the modem is supposed to be programmed to reset as if powered off-then-on. If your modem does not reset this way, you can have all sorts of problems, ranging from the modem leaving the phone line active when the software isn't using it (phone_bill++), to the sort of problem you are describing. > general question: > > How can you set tty speed for 64K bits/sec or 56K bits/sec for data transfer > over ISDN?? You can't; on a normal IBM serial port, you program the UART by programming a divider value. Each of the speed values are manifest bit values for B9600, B19200, etc.. To use non-standard speeds, assuming you are using a non-standard serial card, and not an IBM serial port where you can only twiddle the divider, you have to steal from the allowable bit values. For instance, you could change B110 to mean "set this non-IBM serial port to 64K". In reality, for serial devices with external clocks, you don't *need* to set serial port speed. For internal modems or UART-CSU/DSU pairs, you should be able to match the UART-to-other-chip speed without needing the user to explicitly program the UART (yeah, right, that'll work...). If your driver supports this, and is an integrated device, you could pretty much ignore the user specified baud rate, and "just work". Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199612111848.LAA06756>