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.