Help - Search - Members - Calendar
Full Version: C3000 Serial Port One Way?
OESF Forums > Distros, Development, and Model Specific Forums > Model Specific Forums > C1000/3x00 Hardware
papercrane
I'm attemting to use the serial port (Sharp port with a SerialIO serial cable) as a serial terminal. To test I started up minicom on both my z and PC and set the baud rates and such the same. When I type on the PC nothing happens. When I type on the Z I see what I typed displayed on the PC. I've tried playing with the settings on both ends and I can't get data from the PC to show up on the Z.

I can see three possibilities.
1) The serial port is one way. (I hope this isn't it....)
2) I'm setting something up wrong. (Entirely possible)
3) The serial port is set up as one way by the kernel.

I tend to think it's option 3 as when I rebooted my Z while the serial cable was connected I got kernel/boot output (but only until the sceen came up). One of the lines output is:

CODE
COMMANDLINE= console=ttyS0 root=/dev/mtdblock2 mtdparts=sharpsl-nand:7168k@0k(smf),5120k@7168k(root),-(home) jffs2_orphaned_inodes=delete EQUIPMENT=4 LOGOLANG=1 DEFYEAR=2005 LOGO=1 LAUNCH=q


Anyone have any ideas?
albertr
Try

4) SerialI/O cable has a voltage level problem when using with C1K/C3K.

-albertr
papercrane
So the voltage problem with this particular cable causes data from the other end not be received? I had read in other posts that people have gotten serial connections to work. Was that with the Sharp serial cable? I wish I'd know about this before I blew $35 on this cable. So it's worthless unless I'm doing kernel debugging....
albertr
Yes, Sharp's cable works.
What kernel debugging has to do with voltage mismatch?
-albertr
bam
so if it has a voltage mismatch problem just use a max232 chip with some caps as a go-thru, that should fix the issues and it would be easy to build
omega
actually a max3232 chip would actually work... the max232 needs a five volt power source, while the 3232 will work on 3.3v... should be all you need.

I suggest that if you have a usb-serial cable around, that you try it with the serial i/o cable... newer equipment uses lower voltage thresholds...
papercrane
And for those of us who are not soldering experts? Is there any way to fix this (damn) SerialIO cable or do I need to try to return it and get a Sharp cable?
sidmoraes
QUOTE(omega @ Jun 27 2005, 12:01 AM)
actually a max3232 chip would actually work...  the max232 needs a five volt power source, while the 3232 will work on 3.3v...  should be all you need.

I suggest that if you have a usb-serial cable around, that you try it with the serial i/o cable... newer equipment uses lower voltage thresholds...
*


You need also a inverter. I used a 4069, and I am happy now!
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.
Invision Power Board © 2001-2014 Invision Power Services, Inc.