OESF Portables Forum

Everything Else => Sharp Zaurus => Model Specific Forums => Distros, Development, and Model Specific Forums => Archived Forums => C1000/3x00 Hardware => Topic started by: papercrane on June 24, 2005, 05:23:20 pm

Title: C3000 Serial Port One Way?
Post by: papercrane on June 24, 2005, 05:23:20 pm

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: [Select]

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?

Title: C3000 Serial Port One Way?
Post by: albertr on June 24, 2005, 08:50:14 pm

Try

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

-albertr

Title: C3000 Serial Port One Way?
Post by: papercrane on June 24, 2005, 09:30:52 pm

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....

Title: C3000 Serial Port One Way?
Post by: albertr on June 24, 2005, 10:06:25 pm

Yes, Sharp's cable works.
What kernel debugging has to do with voltage mismatch?
-albertr

Title: C3000 Serial Port One Way?
Post by: bam on June 25, 2005, 12:42:10 am

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

Title: C3000 Serial Port One Way?
Post by: omega on June 27, 2005, 04:01:53 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...

Title: C3000 Serial Port One Way?
Post by: papercrane on June 27, 2005, 04:55:40 pm

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?

Title: C3000 Serial Port One Way?
Post by: sidmoraes on February 18, 2006, 06:32:49 pm

Quote

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...
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You need also a inverter. I used a 4069, and I am happy now!