#yiv1721350468 #yiv915510959 p, #yiv1721350468 #yiv915510959 li
{white-space:pre-wrap;}
On Saturday 22 May 2010 20:46:49 Jim Donovan wrote:
> I have been working with a single-board computer (TS-7250, using the
> built-in linux) which, about three times per second, sends 8-byte messages
> out through COM2 to another device. Very occasionally (it can go 20 hours
> without failing) a message doesn't all get transmitted. Only 7 of the
> eight bytes get sent. On these occasions, the status returned by write(2)
> is "Resource temporarily unavailable".
>
> It seems reasonable to try another write(2) to transmit the eighth byte.
> However, it crashes without returning. We tried with COM1 and the same
> thing happened. This is illogical - we are not using handshaking and the
> UART has no way of knowing what is going on at the other end of the line
This may be quite logical if the UART's FIFO or Buffer get flooded and it is
returning a message back to the CPU.
You don't tell us what Baud rate your running at either ?
> or even whether there is anything there. I have dumped termios and the
> control registers immediately before the crash; no corruption or other
> abnormality is evident.
>
> Before I try a different linux (cut-down debian Potato is available), does
> anyone have any simpler suggestions?
Tried changing Baud rates ?
>
> Thanks,
>
> Jim Donovan
>
regards
Brett Coady
--
SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/
Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
