Serial communication not working until opening arduino serial monitor

[dasoe]

Dear bakercp,

thank you very much for your awesome work!
I have a problem when using ofxSerial with serial communication to arduino on windows. When plugging arduino it does not work: Arduino is found ("successfully setup COM5…"), but no communication happens. "onSerialBuffer seems to never fire. Trying to send something gives me "IO exeption. Error while writing to the serial port. … |ibs\serial\src\impl\win.cc, line 343."
After opening and closing arduino serial monitor it works without problems.

I can produce the problem on a Computers running Windows 10 with both OF 0.9.8. vs and OF 0.9.4 vs as well as on another Computer running Windows 7 OF 0.9.8 vs. ofxIO is stable branch and ofxSerial is master branch in all three cases.
Ubuntu OF 0.9.4. works without any problem.

It's not completely sure this problem is specific to ofxSerial, still I can reproduce it also in example_buffered_serial_device, while ofSerial example works well.
I'd be happy if you had any advise. I'm ready to do further testing of course.

thanks and have a good day!
oe

[dasoe]

Dear all,

Thanks two V4Friend from arduino forum I could solve the issue. Find related post here:
http://forum.arduino.cc/index.php?topic=119557.0
Problem seems to occur when DTR is set to 0, only on some arduinos (in my case micro). Arduino Serial Monitor sets DTR to 1, so only after opening it, it works.
With ofxSerial: calling device.setDataTerminalReady(1); after setting up the device seems to solve the problem.
Why unix behaves differently is unclear to me.

hope this helps & have a good day!
oe

[dasoe]

Dear bakercp,
Dear all,

I have the same problem again, again with Widonws, with an Arduino Micro. This time I use the beautiful ofx::IO::PacketSerialDevice. Here I can not use my former solution device.setDataTerminalReady(1); as I get:

Error C2247 'ofx::IO::SerialDevice::setDataTerminalReady' not accessible because 'ofx::IO::PacketSerialDevice_<ofx::IO::COBSEncoding,0,8192>' uses 'protected' to inherit from 'ofx::IO::BufferedSerialDevice'

I'd be happy for any idea.
Thanks and have a good day!
oe

[bakercp]

@dasoe If you want to use DTR, then you'll need to modify the PacketSerialDevice_ class, as it currently doesn't expose it. It's a pretty easy mod (look at how I selectively expose other methods using the using keyword). I'm happy to accept a pull request for something like this.