Garbled serial line

Micael Henriksson micael.h at
Wed Oct 29 01:39:54 CET 2008

On Wed, Oct 29, 2008 at 1:16 AM, Ben Leslie <benno at> wrote:
> On Sun, Oct 26, 2008 at 9:00 PM, Werner Almesberger <werner at> wrote:
>> Ben Leslie wrote:
>>> Assuming it is the cable, do you know if OpenMoko supplies
>>> replacement cables?
>> I'd suggest you have a look at
>> Sometimes, disconnecting and then reconnecting the debug board
>> cable (at either end) can help. A bad contact there can really
>> cause all kinds of weird issues, some of which you'd never
>> expect to be caused by a bad contact.
> Yeah, tried that a few times :) It does actually seem to make some
> difference. After trying to clean the contacts and reseat very
> carefully I was able to get more characters but it was still mostly
> garbled.
>> The mismatched bit rate theory is interesting, though. If
>> reconnecting the cable (may need a few tries) doesn't help and
>> if you have access to an oscilloscope, gathering the signal on
>> TX/RX (pins 1 and 2 of J10 on the debug board) may be useful.
> It is amazing how few oscilloscopes they have in hotel rooms these
> days, and the concierge just gives me a  blank stare when I ask to use
> his :)

I connected my debug board to my GTA01 after not using it for three
month and also got a lot of interesting stuff on the serial port. JTAG
works OK and after some insert/remove operations of the plastic cable
I started to _receive_ correct serial data most of the time, but
nothing is ever sent. If I set u-boot to serial console, I see the
prompt but nothing happen when I type...


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