Arduino serial communication with PC (TeraTerm)

Using Arduino Programming Questions
1

I wrote a simple serial program using Arduino Mega 2560, it is connected to COMPORT 10. Here is the program I Wrote,

void setup() 
{           
  Serial.begin(9600);
}

void loop() 
{
  Serial.println("HELLO"); 
  delay(1000); //Send every one second           
}

Now, I tried to send this message "Hello" directly to TeraTerm (COMPORT 1, for this I just hooked up Tx and Rx to the Arduino's Rx0 and Tx0. I have also connected the GND of arduino to the pin no 5 of the serial connector. Doing this I do receive message in my TeraTerm screen but the received message doesn't make sense, its receiving garbage. Its not the case of mismatch of baud rate I am using 9600 on both sides.

However I do receive message "HELLO" in the serial monitor. Is there something I am doing wrong that I am not receiving message on TeraTerm, OR can i not connect the TX0 and RX0 of Arduino directly to my PC?

2

You cannot connect Tx and Rx to modern PCs that only have USB connectors. But the normal USB connection between the Arduino and the PC effectively connects Tx and Rx to the PC.

If Terra Term is a PC program it will need to open the appropriate COM port to talk to the Arduino.

If Terra Term is not a PC program please post a link to its datasheet.

...R

3

Now, I tried to send this message "Hello" directly to TeraTerm (COMPORT 1, for this I just hooked up Tx and Rx to the Arduino's Rx0 and Tx0.

If you mean via a 9 or 25 way D-type, be prepared to say bye-bye to your Arduino.
(you're missing an inverter and level-shifter)

4

Now, I tried to send this message "Hello" directly to TeraTerm (COMPORT 1,

I don't know anything about TeraTerm, but you probably should use the virtual comport established on the pc that the serial monitor uses. Directly wiring your arduino to a serial port jack on your pc might damage your arduino as the hardware port may be operating at +-12v instead of 5v.

5

thanks everyone I solved the problem. Arduino serial port cannot be directly connected to the PC serial port. The Voltage level is not same in Arduino and PC, so i added the level shifter MAX232 in between and connected both the devices, now it works fine.

Thanks for your suggestions.