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Bluetooth HC-05 connecting issue

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engr_joni_ee

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Hi,

I am struggling with connecting bluetooth module hc-05 to microcontroller. I have made the following connections.

Pin 1: En/Key : Gnd
Pin 2: VCC : + 5V
Pin 3: Gnd : Gnd
Pin 4: Rx : Connected to Tx of Microcontroller
Pin 5: Tx : Connected to Rx of Microcontroller
Pin 6: State: Not connected

I guess the connections are right or maybe I am missing something. When I send a character from the bluetooth app, it does not toggle the LED connected to the microcontroller.
 

it does not toggle the LED connected to the microcontroller.
Means your controller toggles the LED if it receives a character? Sure HC-05 is set to the same baudrate as microcontroller?

Does the HC-05 LED signal connection to the master?
 

Means your controller toggles the LED if it receives a character? Sure HC-05 is set to the same baudrate as microcontroller?

Does the HC-05 LED signal connection to the master?

The microcontroller suppose to toggle the LED when a character is received through UART. I have tested the microcontroller program on breadboard. If I send command from PC using serial terminal, it toggle the LED. This means that microcontroller program is working.

Latter I connect the microcontroller to HC-05. I have powered up the microcontroller with 3.3 V when I connect to HC-05. The smart phone find the device HC-05. I just pair it but not able to connect in the App.

When I power up the HC-05 and pair it, the status light flashes two times per second but when I try connecting the device in the App it gives two flashes per second and then off for one second and then two flashes.
 

The default baud rate of HC-05 in command mode is 38400 and 9600 in data mode. I am using 9600 in microcontroller.

Pin 1: En/Key has to be connected to ground for data mode.
--- Updated ---

I have found the mistake. I did not swap the Tx and Rx pins. Now it is working. I have connected Tx and Rx in the following way.

Pin 4: Tx : Connected to Rx of Microcontroller
Pin 5: Rx : Connected to Tx of Microcontroller
 
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