Weird problem on rs232 vs USB-serial...

Jiri Gaisler jiri at
Tue Feb 24 18:04:08 UTC 2009

If you load your application via grmon, check that the
detected target frequency is correct. Grmon will use
this frequency to set the baud rate of the UARTs.
If the frequency is wrong, the baud rate will be
set wrong and your host UART will not receive the
characters. Try to use the -freq XX option when starting
grmon to specify the target system frequency.


mike wrote:
> Thanks Chris,
> The interrupts were checked out fine. I was able to see the bootrom
> messages (a very basic bootrom) when it came up. The problem
> occurred only after I loaded an RTEMS app (with the RTEMS shell
> and some debug codes) to ram, then jump to it that I didn't see anything.
> Repeating the same sequence with the Leon2 uart connected to
> a USB<->serial adapter (to the same Linux host) worked fine.
> The simple RTEMS app just use /dev/console for i/o and it didn't
> seems that it could have anything wrong with it as it worked as it's
> supposed to **when connected to usb<->serial** without changing
> anything.
> That's really weird...
>  -mike-
> Chris Johns wrote:
>> Check /proc/interrupts to see if the kernel is getting interrupts from 
>> the UART for ttyS1. I would not bother with USB interrupts as this is 
>> a shared bus and the interrupt count to USB serial I/O does not match 
>> easily.
>> I would also connect just a cable to the port and connect together the 
>> TX/RX pins then type something on Minicom. You should see the 
>> interrupt count go up by 2 for each character pressed. This will help 
>> you isolate the host from cable from target.
>> Regards
>> Chris
> _______________________________________________
> rtems-users mailing list
> rtems-users at

More information about the users mailing list