ARDUINO PIN 0,1

Projects Networking, Protocols, and Devices
1

While using pin hc-05 and arduino
why do I have to disconnect from pin 0,1
to upload the code then connect them back ?

2

Another question
what's the different between at+bind
and at+link
and at+pair ?

3

MovieFan1995:
While using pin hc-05 and arduino
why do I have to disconnect from pin 0,1
to upload the code then connect them back ?

Because those pins are also used to upload the sketch to your Arduino board. When the HC-05 is connected, it interferes with the upload. The USB jack on your Arduino board is connected to a USB to TTL serial adapter chip which allows your computer to communicate with the board via a virtual COM port. That USB to TTL serial adapter chip is connected to the primary microcontroller on your Arduino board via pins 0 and 1. Those are a hardware serial port on the microcontroller. Pins 0 and 1 are also broken out to headers on the board to allow you to use them for other purposes. Generally, it's best to leave those pins to be used only for communication with the computer, but sometimes that is not possible.