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1  Topics / Science and Measurement / Data logging with Mega 2560 using Max3232 on: January 06, 2013, 05:55:14 am
Hi all,

I am trying to use the Serial1, Serial2 and Serial 3 (pin 14-19) of my arduino 2560 to read digital signal of my lab's instruments. I used a RS232 to TTL board (MAX3232) to convert the digital signals from the instruments, however there is no response.

I did some simple test.

i  sent out some letters through the MAX3232 and the used a rs232 to usb converter to convert the signal and my computer can receive the letters and displayed using the arduino software. however, when i send back some letters, the ardunio could not receive.

Here is the code:

void setup(){
  pinMode(13, OUTPUT);
  digitalWrite(13, LOW);

void loop(){
   // to display something in arduino software
    Serial1.write("Waiting Signal....");
    // to see if mega2560 recieve anything from the computer
    if (Serial1.available()){
      int aaa =;
      digitalWrite(13, HIGH);

actually i received some random number for the variable "aaa" and the LED always turned on.

Do you know how can I change the code so that I can receive digitial signal from rs232 using max3232 and the mega 2560 board.

Hope you can help!

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