Sending command via Arduino USB port causes reset

[bluespider42]

I am using an Arduino Mega 2560 and PyCmdMessenger. When I send a simple acknowledge type message to the Arduino through the built-in USB/Serial interface it causes a reset of the Arduino. However if I connect a external USB/Serial convertor directly to the Tx/Rx pins of the Arduino then it works , no problem. The Arduino USB/Serial port works normally when not using CmdMessenger (ie for looking at debugging messages in tera term). I can't work out what is causing the reset - or is this possibly a problem with PyCmdMessenger and the way it handles connections?

[valkuc]

Probably this is you case https://github.com/thijse/Arduino-CmdMessenger/issues/10 However this repo is not related to PyCmdMessenger, if what is written in issue above will not help, try go to https://github.com/harmsm/PyCmdMessenger

[harmsm]

I maintain PyCmdMessenger and I'm happy to help with the PyCmdMessenger side if this isn't #10. Just create an issue over there. (I've never seen this failure mode, but then, I've never plugged in a Mega 2560...)

Mike

On Sep 16, 2016 5:15 AM, "Valeriy Kucherenko" notifications@github.com wrote:

Probably this is you case #10 https://github.com/thijse/Arduino-CmdMessenger/issues/10 However this repo is not related to PyCmdMessenger, if what is written in issue above will not help, try go to https://github.com/harmsm/PyCmdMessenger

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[bluespider42]

Thanks, I think this probably is my issue - or at least related. When in #10 you said try setting"DTREnable to true and false" did you mean on the Arduino or the PC side? I couldn't find a way of doing it in the Arduino software but found a lot of references to setting the reset line manually with a resistor. But I'd rather not have to do that every time I wanted to re-flash it! If it needs doing on the PC side then I'll move this conversation over to the PyCmdMessenger page as the PyCmdMessenger handles the actual serial connection. I did try adding in a self.comm.setDTR(value) into the arduino.py of PyCmdMessenger but I think that was only having an affect after the port was opened (and after the reset had occurred).

[valkuc]

This is related to PC side.

[bluespider42]

Thanks