What Tx Rx pins for Mega and HC05?

Projects General Guidance
1

I am installing a HC05 Bluetooth module on to an Arduino Mega and was wonder which Rx and Tx pins I should be using. Obviously pins 0 and 1 and 14 through 19 are marked as such. Can any pin be used for Rx and Tx?

I am using the SoftwareSerial library in which you can define which pins they are, as in

SoftwareSerial BTserial(4, 6); // RX , TX

Is there a preferred set of pins? I am using the voltage resistor divider to make sure the Rx on the HC05 receives only 3.3V.

2

There´s no need to use SoftwareSerial if your board has more than one hardware serial ports. Arduino MEGA has 4 of them:

Serial: 0 (RX) and 1 (TX);
Serial1: 19 (RX) and 18 (TX);
Serial2: 17 (RX) and 16 (TX);
Serial3: 15 (RX) and 14 (TX).

You can choose one of those pairs and connect the HC-05 module.

Sounds good!

3

Yes, and the Mega pins are documented on the product page on this site.

4

Don't use pin 0, 1, because they are already used by the Serial<>USB chip.
Don't use SoftwareSerial on a Mega.

There is a multiSerial example for a Mega in the IDE.
Leo..

5

Thank you everyone. It's working now. I am using Serial1 (pins 19 and 18).