Problems with USB to serial adaptor

Jon Masters jonathan at jonmasters.org
Mon Jan 31 05:05:13 EST 2005


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David Kramer wrote:

| Jon Masters wrote, On 01/30/2005 07:47 PM:
|
|> [ apologies for lack of reply threading, I just signed up and don't have
|> a handy message to reply to. btw, hi. I'm going to be coming to Boston
|> LinuxWorld in a couple of weeks and figured I might aswell delurk now.
|> I'm in the UK now but will be doing a road trip down from Ottawa. ]

| Great.  If you see me, say hello.  I'll be the overweight guy in the
| geeky t-shirt.   ;)

I'll be sure you bear that in mind - since I have a vanity problem,
there's a bunch of photos of what I look like on jonmasters.org.

|> He wants to talk to a gdb stub on the embedded target, most likely.
|> Stubs are gdb clients that let you debug stuff from a host box -
|> especially useful if you don't have ethernet on the board since with
|> ethernet he could just use a stub running on a TCP/IP port.

| Just so.

Good good.

| What is happening is that we have this embedded development board.  We
| cross-compile our program under Linux to work with the ARM7 processor on
| the dev board.  gdb has the ability to load the program onto the board
| and run it remotely, giving full debugging output, over a serial
| connection.  So we hook the board up to the Linux box with a serial
| cable, run gdb, tell it to load the application on to the board on the
| given serial port, and then run it in debugging mode.
|
| It works well.  We've been doing this on a desktop, and now we want to
| do it using my spiffy new, but legacy-port-deprived, Thinkpad T42.
| Hence, the USB to Serial converter.

I've had a few issues with using those, but have a similar problem with
my Powerbook talking to random stuff. I'm building a Linux powered
roboduck for a certain magazine at the moment and am having to use a
cheap and nasty dongle. Did you actually try using a remote target:

jcm at perihelion:~$ gdb
GNU gdb 6.1-debian
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain
conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i386-linux".
(gdb) target remote /dev/ttyUSB0
Remote debugging using /dev/ttyUSB0

Incidentally, if you think that's run, try using the Xilinx tools!

|> | Did they wire the pins in a nonstandard way
|>
|> He may not have working hardware handshaking on a USB adapter so might
|> want to switch to standard 8N1 non-hardware handshaking at 9600bps.

| How would I do that?

Er...^a-O is probably the option to get in to Minicom Options. Go to
those serial options and change them as suggested, also the dial strings
can be chucked out.

|> | If this device is compatible with minicom, you still need to know
|> | which modem settings to try.
|>
|> Take out the dial strings from the Minicom Options, or use another
|> client such as kermit or something similar. Personally, I still use
|> minicom despite the recommendations of various others, because I'm
|> stubborn and really need to be convinced that I am wrong :-)

| OK, I didn't try that because I thought minicom wouldn't actually
| consider itself "online" unless it got a CD.

Nah, it's a bit more intelligent than that. Note "a bit", there's
probably a lot better replacements for it these days :-)

Jon.
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