Teensy LC with NS-RS232-01

I am connecting an NS-RS232-01 TTL Serial board to the Teensy LC.
RS-232 signal works fine with Hyper Terminal sending data so long as I connect USB to my PC. If I use an external Power supply such as a phone charger (tried 5 different ones) the Teensy program works (led blinking appropriately) but no more rs-232 data. This is a Teensy LC board. I tried different grounds and things. Checked the white ground wire for continuity etc... I am thinking it has something to do with a common ground but I am not sure.

Thank you all in advance

www.scaleprogrammers.com

Hard to say without seeing your code.

Many times it is due to having code that looks something like: while (!serial) ;
Where it waits for the USB serial port to be available...

KurtE said:

Hard to say without seeing your code.

Many times it is due to having code that looks something like: while (!serial) ;
Where it waits for the USB serial port to be available...

Click to expand...

Thank you Kurt E, That got me thinking and yes I send out as well for a dual purpose, a keyboard.write command. Once I removed any reference to that and did only serial commands it did work on a cell phone charger. Beauties Thank you so much, I spent a whole bunch of time on this and was at the give up point.

Glad you found it.