Re: 2.4.22 usbserial/pl2303 oops

Simon Vogl
2003-10-29T09:06:32Z

I have a different problem with the pl2303 module, but have
no clue where to search: I have an ericsson cradle that I
check repeatedly if a cell phone is plugged in or not.

I wrote a small program that sends AT commands to the modem
every few seconds, and when an OK arrives, everythings fine.
It is indeed fine, until I unplug the phone and insert it again:
The program writes the 'AT\r\n' correctly, and I do get an answer
of the right length, but the read buffer does contain only zeros,
although the right length is returned.

Some things get me out of this loop of hell:
o reloading the pl2303 module
o when I re-insert the phone, I get correct data about every
tenth try.
o minicom seems to do additional initialization that cures
the problem as well.
I looked through straces of minicom as well as the other programs,
but did not find any significant difference. I did also load pl2303
with debug on, and found that it receives the right values in its
internal buffer, but they are not getting out of the module.

Can anyone give me a clue where I should look next?

thanks
Simon

--
------------------------------------------------
Dr. Simon Vogl
Department of Computer Science
Johannes Kepler University of Linz
Altenberger Straße 69
A-4040 Linz - Austria

Tel: +43 70 2468 8517 vogl@soft.uni-linz.ac.at
Fax: +43 70 2468 8426 www.soft.uni-linz.ac.at