Re: [ECOS] EB40A (AT91) serial port oddness

[Tom Lynn <tom dot lynn at hypertag dot com>]

Nick Garnett wrote:

> When your application is running, there will be no traffic on the
> debug channel. So there should be no interference from that, so long
> as you are not doing diag_printf()s. The 4 byte jumps are suspicious,
> I agree, but you get contiguous runs too, so the problem is
> intermittent.
>
> The AT91 serial devices are nasty and a lot of work has gone in to
> making them perform correctly. However, that was mostly on the receive
> side. Transmission should be much simpler. I've run a variety of
> serial tests on the AT91's in the past, some of which test high
> throughput, with no difficulties.
>
> Make sure you have the very latest version of the cvs repository.
>
> What are you using to recieve the characters at the other end? minicom
> on Linux or HyperTerminal on Windows are known to work well.

Thanks for the helpful suggestions.  It looks like it was a problem with 
driving the cable-replacement hardware I've been using and not the 
serial port itself after all.  I was misled by that fact that the 
following Python code which I'd expect to be equivalent to the eCos code 
works as expected:

from serial import Serial  # http://pyserial.sourceforge.net
from time import sleep

s = Serial("COM1", 9600, 8, 'N', 1, xonxoff=0, rtscts=0, writeTimeout=None)
while 1:
   s.write("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-=\n")
   sleep(1)

So it looks like I'll be digging around comparing the internals of the 
two for a while.  Any suggestions on what to look for would be much 
appreciated.

I'd still be interested to know how you turn off the debug output too, 
since I suspect I'll have more serial port diagnosis in the near 
future.  My suspicion is that so few people want to turn it off that 
turning it off no longer works.

Tom

--
Tom Lynn, Software Engineer, Hypertag Ltd.
William Gates Building, JJ Thomson Avenue, Cambridge CB3 0FD

Tel: 01223 763710   Fax: 08714 335288   Web: www.hypertag.com


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