[time-nuts] Linux code for Prologix GPIB/USB
SAIDJACK at aol.com
SAIDJACK at aol.com
Sun Feb 25 19:27:04 EST 2007
In a message dated 2/25/2007 22:20:09 W. Europe Standard Time,
hmurray at megapathdsl.net writes:
I found it also went into blinking-LED mode if I sent it another command too
quickly and didn't have flow control working. It works fine without flow
control as long as you pause before sending it another command. At least
for
what I'm doing.
Hi there,
I found the same thing. It's a bug in the Prologix firmware: a micro is
connected to an FDDI (or similar) USB to RS232 (TTL level) converter, and the
micro is extremely sensitive to anything sent over the RS232 TTL interface.
Keep in mind that the USB is being used as a vehicle for the underlying
RS-232 connection, so Baud-rates etc still apply, even over the USB.
That micro get's unhappy very easily and starts blinking, such as when
commands are sent to it too quickly or the flow control is not right for some
reason.
Once it blinks, it's kind of stupid and doesen't try to recover (after a
time-out etc) - a hard-reset is needed to get it out of that mode.
I modified my board to have a true RS232 to GPIB connection, bypassing the
FTDDI chip, and that was not easy due to this sensitivity of the Micro's
firmware.
bye,
Said
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