USB Conflict Problem

I have a problem communicating between my Toshiba laptop and my Arduino Uno, and any help would be much appreciated by a newbie.

In case it’s relevant, the laptop is an old 7140 Portege with a single USB port. The port is low speed (9600).

When I installed the Arduino IDE the Uno came up on port Com4. Everything seemed ok, and I was able to upload sketches and run them. The problem came when I tried to use serial comms from the Uno back to the PC. This works, but it seems to tie up the serial bus, so that when I try to upload a new sketch I get an error message saying Com4 is already in use. When I look at “Ports” in the Tools menu, Com4 no longer shows, and the only way I can regain control is to switch everything off and start again!

Any ideas much appreciated.

Mike

I have exactly the same problem, have you managed to resolve it.
Richard

Richard

I think I have fixed it. Using Device Manager on the PC I went into the Ports file and changed Flow Control on the Arduino port (COM 4 on my set up) from OFF to Hardware. No more conflict, though I do now find that I reset the Arduino every time I open the Serial Monitor (but I can live with that for the time being).

HTH

Mike

Thanks Mike, that seems to be the answer
Richard

mikeso51:
I do now find that I reset the Arduino every time I open the Serial Monitor (but I can live with that for the time being).

That's normal, intentional behavior. It's a feature called "Auto-Reset".

You can avoid the reset with: [MOD] Arduino Enhanced Release 1.0.5 for Windows (installer, drivers, etc) +SRC - Libraries - Arduino Forum

Reset is still available: