This could be due to the Arduino sketch you are using. While using the Arduino IDE the ttyGS0 is used do upload the sketch to the board and for the interactions in the Serial Monitor. If your sketch is using the Serial monitor for functions like serial.write or serial.print you will have problems if the USB is not connected, because, that is the port the sketch will use to send and receive information. If the sketch doesn’t find the ttyGS0 (USB port) connected, it will not be able to run the sketch for configuring the WiFi connection.
Could you post the sketch you are using?
Which image are you using? (configure_edison --version)
Initially I used serial prints in the code for debugging purposes. With this sketch (ProximityDetectionTCPWiFiDebug.ino), I mentioned my earlier observations. Now after commenting out logic related to Serial communication (ProximityDetectionTCPWiFiRelease.ino), I am not able to connect even with the WiFi Accesspoint.
(configure_edison --version) doesn't print any version. It says invalid command.
I am attaching both the sketches for your reference.
I have figured out the issue with ProximityDetectionTCPWiFiRelease.ino sketch. Now I have cleaned up the code i.e. removed all un-necessary code involving Serial prints. But still issue mentioned in original post is there.
1. If I keep on connecting USB cable + External power supply (9V, 1A), then WiFi connection seems stable. Ping from peer computer works fine.
2. If I just connect Edison board with external power supply (9V, 1A), there is lot of packet loss. Ping doesn't get replies.
Attaching updated sketch for your reference.
You should be able to run the configure_edison --version command on the Terminal Console. This could be due to a firmware issue, I suggest you to flash your board with the latest image.
How are you testing your code, I would like to test it in the same way.
I have flashed the latest (Release 2.1) yocto image mentioned on the page IoT - Intel® Edison Board Download | Intel® Developer Zone.
After this I end up with a new issue i.e. Arduino sketch doesn’t run if USB cable is disconnected from the host PC.
After checking on google, I have found that it is a known issue and there is a workaround to resolve this as mentioned on https://communities.intel.com/thread/78269?start=0&tstart=0.
After implementing this workaround now things are working fine. The Arduino Sketch is working as expected without connecting the USB cable now. So the original issue got resolved.
Thanks for your help.
Arun Kumar Saini