I want to use an Android app to control my robot car. There are many apps to choose from, but all use the TX/RX pins to communicate. I want to display the input from the Android on the Serial port, but this requires using two different Serial ports: one for the Android communication and a different port to display the dialog. How do I configure Visual Micro to accomplish this?

Tim,

I am using debugging AND I use the Serial.print command to display what is happening inside my code.

Tim,

Using SoftwareSerial, I got my Android phone to talk with the robot and have the diagnostic messages show up on a serial output window. 
I have the HC-05 module connected to pins 10 and 11. 

All serial ports in VM are pointing to a single COM port. This works just fine until I unplug the USB connection. At that point, any command I send from the terminal emulator on my phone causes the robot code to reboot. 

I can start the motors from my phone, but if I disconnect the USB, the motors stop too, even though they have their own 9V battery supply.

Since the robot is not connected to my PC, any output it generates is lost, so I don't know exactly what is happening. 

Any suggestions?

Tim,

I am using software serial to communicate with the HC-05 over D2 and D3. I use Serial.print to display diagnostic output. I have added a command to my code that turns off all serial output on the hunch that the act of writing to serial output when the USB connection to my PC is disconnected, that may cause the fault. It appears, however that that did not fix the problem. 

So my question now has two parts:
1) How can I capture what is causing the fault when the robot is disconnected from the USB link?
2) When the USB is disconnected, what changes internally?

Thanks for your support.

Bob