I have read a lot of posts about SerialUSB communication issues but nothing seems to describe the issue I am having.
I can flash as simple as the ASCIITable modified example modified to use SerialUSB or something like GVRET which can be found at: GitHub - collin80/GVRET: Generalized Vehicle Reverse Engineering Tool - firmware for Arduino Due based boards,
When I flash the code (using either programming or native ports) I can connect to the native port one time after the code is flashed. But, this is using another COM port representing the native port.
For example if I flash with the native port com 8 then when the board resets, the native port is now connected to COM9. If I open COM9 then everything works as expected (lists out ASCII table or I can access the GVRET configuration menu. But, if I close the serial monitor, the previous connected port (COM9 which was identified as the native port) disappears.
The previous native port (identified at com8) is still there but when I open the monitor nothing happens.
I can reset the board, unplug and re-plug the USB it back in an nothing.
This happens both when I power off of external power supply or if I power off of USB.
I only can reconnect after I re-flash the board but it seems to be a "one time thing".
Thank you in advance.