It is hoped that the following diagram will help you to find the technical reason why we should temporarily disconnect the jumper wires from TX/RX pins of the UNO from the external circuits before uploading sketch into the UNO?
It is hoped that the following diagram will help you to find the technical reason why we should temporarily disconnect the jumper wires from TX/RX pins of the UNO from the external circuits before uploading sketch into the UNO?