🚀 go-pugleaf

Robert Andrew Ryan <rr2b+@andrew.cmu.edu> writes:
> I am trying to configure some RTs as X terminals to be connected to our
> network via slip.  They are floor models and have two built in serial
> ports, however I have been unable to get reliable results at over 4800
> baud, I get garbage and dropped characters.

The device driver in the kernel for the serial ports on the mother board
does not work reliably at speed over 2400 baud.  The device driver needs
to be rewritten (and I doubt that anyone will do it.)

> Also if I have hardware flow control set on in the modem once I connect
> to our annex box it just sits there, if I switch the modem back to
> XON/XOFF and disconnect and re-connect to the modem (before it drops the
> annex connection) I get a bunch of backed up data from the annex.  When
> connected to an RS/6000 9600 baud and hardware flow control seem to work
> ok with the same annex.

The device drivers for either type of serial port did not support hardware
flow control.

> I seem to remember reading a post here maybe a year ago about the chip
> driving the serial line having only a 1 character buffer, but that it
> was pin compatible with one with a 16 character buffer.  Or was that
> about the 4 port serial card?

The AT Serial/Parallel card and the 4 port (unbufferd) card uses a NS16450
uart.  This can be replaced with a NS16550AFN.  (I just clipped the old
uart out of an AT Serial/Parallel card and soldered in a socket and inserted
the NS16550AFN into the socket.)  This will provide reliable connections
up to 9600 baud.  To achieve even faster speeds, compile the kernel with
the a new copy of asy.c that was hacked over by Peter Honeyman and then
lightly modified by me.  The new chip and software together reliably handle
38,400 bps and hardware flow control.

Hope this helps, ...Tim

          Tim Theisen           Systems Programmer
Internet: tim@cs.wisc.edu       Department of Computer Sciences
    UUCP: uwvax!tim             University of Wisconsin-Madison
   Phone: (608)262-0438         1210 West Dayton Street
     FAX: (608)262-9777         Madison, WI   53706