Weird problem on rs232 vs USB-serial...
jiri at gaisler.com
Tue Feb 24 22:17:27 UTC 2009
The problem might be with your boot loader. We have created many
RTEMS boot images with mkprom/mkprom2 and never seen this problem.
If you use LEON2FT, then you also have to wash all registers
and memory to initialize the BCH checksum, before launching RTEMS ...
> Thanks Jiri,
> 1) with grmon, everything was fine. The target DSU was connect on ttyS0
> and Uart on ttyS1.
> We always used 'grmon -freq 66 -leon2', and it connected fine. 'load
> xxx' then 'run' was fine as
> I could see the RTEMS shell coming up on ttyS1 (with minicom connected to
> ttyS1, 38400, 8N1 and no flow control). The target has a basic bootrom
> we were not using it in this case. The exe file was an executable
> linked and
> resolved to 0x41000000 (for our purpose).
> 2) Now, when we were not using grmon, on power up the target, the bootrom
> messages came up on ttyS1 as expected. We then loaded the same RTEMS app
> to ram at 0x41000000 with the bootrom ( and with minicom raw upload),
> with a binary
> file produced from .exe in (1) above by sparc-rtems-objcopy -O binary,
> then jump to 0x41000000. Nothing on ttyS1
> 3) the funny thing is, with the target uart port connected to
> usb<->serial, repeating
> (2) above worked as expected (RTEMS shell came up on ttyUSB0, with
> minicom connected to ttyUSB0, same 38400, 8N1, no flow control.
> Anything else I can look? Thanks!
> - the bootrom set the target uart to 38400, no flow control , 8N1
> - I set it (0x80000078 & 7c, UART control/scaler) again in the RTEMS
> app, just to test. No change.
> - I use shell.c in the RTEMS tree. I also set B38400 there. No change.
> Jiri Gaisler wrote:
>> 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.
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