I bought Arduino Mega in order to use additional Serial ports. I wrote the following code:
void setup() {
// initialize serial ports:
Serial.begin(9600);
Serial1.begin(9600);
Serial2.begin(9600);
Serial3.begin(9600);
}
void loop() {
Serial.write("Testing Serial 0\n");
delay(1000);
Serial1.write("Testing Serial 1\n");
delay(1000);
Serial2.write("Testing Serial 2\n");
delay(1000);
Serial3.write("Testing Serial 3\n");
delay(1000);
}
However, I am getting the following output. What happens to Serial1, Serial2, and Serial3. Is there any magic to activate the other ports? Again this is Arduino MEGA board. ( I searched the web and did not find anything pertaining to this topic. I assume it must be something very obvious that I have missed).
Testing Serial 0
Testing Serial 0
Testing Serial 0
Testing Serial 0
The serial ports all go to the pin headers along the side (see the silkscreen markings for RX0 and TX0 through RX3 and TX3). Additionally, Serial0 gets routed through to the USB port. The Serial Monitor will only ever see one serial port at a time (Serial0). The other 3 serial ports (actually more properly called UART ports) are there for connecting to other devices who communicate via UART/serial communication. If you want to communicate to a computer with those serials, you will need to add a chip that does the conversion from UART to either RS323 or USB for you.
FTDI does have a nifty chip that takes 4 UARTs and puts them on a single USB. I think it's SMT only though, but they do have a development/breakout board available from them for £21.50 or from Mouser for $29.90. With that board (or similar) you could communicate with up to all 4 Mega UARTs, or monitor both RX and TX of up to 2 UARTs with just one more USB port (in addition to the USB port being used for programming your Mega).