I'm on Win7 64, Arduino Uno, visible in the Device Manger under "Ports" as "Comm. Port COM4". I have a simple, working sketch in which I send simple commands to the Uno via the serial port. Everything works. However, after sending two commands, COM4 becomes unavailable. At that point, issuing "mode …

Win7 x64, Arduino Uno: com port gets disabled after use

Coding_Badly May 11, 2012, 5:22am 4

Does the problem persist if the relay board is disconnected / removed?

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