0 Replies Latest reply on Nov 26, 2018 4:40 AM by mik.mary

    Galileo board - Using two serial i/o interconnections - Arduino Serial2 through 3.5mm jack

    mik.mary

      I'm using the Galileo board with the Arduino-IDE. I'm using the board on 3.3V by setting IOREF.

       

      I need to have 2 serial ports available to connect to two devices working on 3.3V.
      I'm currently using:

      -Serial: USB communication to PC

      -Serial1: pin 0-1 connection to one device

       

      I need another serial port for the other device but:

      -Serial2 seems connected to the 3.5mm jack
      -Software serial Arduino library is not supported

       

      Following the first possibility, I connected a jack, opened the cable and connected the internal TX-RX wires to my second device, but it doesn't work.

       

      I checked the interconnections with a multimiter and they are ok, so the problem isn't in faulty cables.
      Still the jack works on 5V, so I put a voltage regulator on the interconnection to translate the 5V into 3.3V.

       

      I checked the serial communication with a logic analyzer (before and after the voltage regulator) and nothing is sent through the RX-TX lines of the jack.


      My program is simply something like:

       

      void setup() {

        Serial.begin(9600); //USB communication

        Serial1.begin(19200); //first device pin 0-1

        Serial2.begin(19200); //second device jack
        ...
      }

       

      void loop() {
           ...

           //take string str from USB Serial
           ...
           //send it to the 2 devices
          Serial1.print(str);
          Serial2.print(str);
          //if the string is received, the devices send and ACK acknowlegde on the serial line and I print it on the PC screen.

           ...

      }

       

      It compiles without any problem Serial1 works perfectly, but Serial2, which is the jack, remains silent.
      How can I solve the problem?