Weird problem on rs232 vs USB-serial...

mike antispam21 at
Tue Feb 24 17:47:23 UTC 2009

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

That's really weird...

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

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