High speed serial io @ 38.4K

DanKarron at UCBVAX.BERKELEY.EDU DanKarron at UCBVAX.BERKELEY.EDU
Fri Mar 8 00:48:59 AEST 1991


First try a loopback test after you set the ioctl bits on the port.

Then send a LARGE file of some character (I like cap U because it represents
an alternating bit pattern and one bit errors stick out in the field of U's.

Sit back and watch the echo from the port. 

That will prove the port. Most problems are caused by interrupt response time
from the kernel at high speed and lack of port buffer space. 

You will need FAST handshake response time on the part of both parties, and
this is another problem. Again, make certain that you use the /dev/ttyf{2,3,4}
port. I have found that /dev/ttyf1 does not work as well as the others
even with the getty turned off.

I have patched and optimized a version of kermit to run at max machine. 
I find it is a good diagnostic tool. If you want a copy, please drop me a
note.

You might want to eliminate the parity bit as it will only slow down your
line. What are you talking to ? How do you know that your peripheral can
manage at high speeds. How does it behave at slower speeds.

Cheers!
+-----------------------------------------------------------------------------+
| karron at nyu.edu (E-mail alias that will always find me)                      |
| Fax: 212 263 7190           *           Dan Karron, Research Associate      |
| . . . . . . . . . . . . . . *           New York University Medical Center  |
| 560 First Avenue           \*\    Pager <1> (212) 397 9330                  |
| New York, New York 10016    \**\        <2> 10896   <3> <your-number-here>  |
| (212) 263 5210               \***\_________________________________________ |
| Main machine: karron.med.nyu.edu (128.122.135.3) IRIS 85GT                  |
+-----------------------------------------------------------------------------+



More information about the Comp.sys.sgi mailing list