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I2C communication between PIC16F877a and Raspberry pi 3

alexvarghese

hi,

Can any one help me to start a communication with PIC 16f877a controller and raspberry pi  through I2C protocol .i am new to both Raspberry pi and Pic controller .i know only the basics in Pic and raspberry pi . PIC will sense the data from a ultrasonic sensor. the sensed data has to be transfer to the Rpi .

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  • 0

    Hi,

     

    This is a bit of an ambitious first project. i2c communications is not very easy: Although the protocol allows the slave (your PIC in this case) to slow down communications from the master (the PI in this case), the hardware on the PI has a bug that makes this unreliable.

     

    So in practice, the pic will have to be VERY fast, to be sure that it won't slow down communication with the pi to work around the bug.

     

    I would recommend that you use the UART to communicate with the PIC.

    It is reasonably easy to have something like:

    if (character_available () ) {

       character = get_character ();

       if (character == '\n') { 

          process_command (buffer);

          pos = 0;

       }  else {

         print_character (character);

         buffer[pos++] = character;

       }

     

    So now your PIC can accept commands from the pi. You can use a terminal program like minicom to communicate with your PIC. This allows for easy debugging as well.

     

    Just like i2c, this requires you to hook up two data-wires between the pi and the PIC. (besides power and ground).

     

    I worked with PIC microcontrollers early this century, but I've switched to other microcontrollers since then. So I'm not familiar with the PIC specific details. But I do know stuff about PI, I2C and microcontrollers in general.

     

    (The example code above is slightly too simple: For example, you'll quickly appreciate adding something like:

     

    if ((pos > 0) && (character == DELETE)) {     pos--;

         print_string ("\b \b");

      }

Reply
  • 0

    Hi,

     

    This is a bit of an ambitious first project. i2c communications is not very easy: Although the protocol allows the slave (your PIC in this case) to slow down communications from the master (the PI in this case), the hardware on the PI has a bug that makes this unreliable.

     

    So in practice, the pic will have to be VERY fast, to be sure that it won't slow down communication with the pi to work around the bug.

     

    I would recommend that you use the UART to communicate with the PIC.

    It is reasonably easy to have something like:

    if (character_available () ) {

       character = get_character ();

       if (character == '\n') { 

          process_command (buffer);

          pos = 0;

       }  else {

         print_character (character);

         buffer[pos++] = character;

       }

     

    So now your PIC can accept commands from the pi. You can use a terminal program like minicom to communicate with your PIC. This allows for easy debugging as well.

     

    Just like i2c, this requires you to hook up two data-wires between the pi and the PIC. (besides power and ground).

     

    I worked with PIC microcontrollers early this century, but I've switched to other microcontrollers since then. So I'm not familiar with the PIC specific details. But I do know stuff about PI, I2C and microcontrollers in general.

     

    (The example code above is slightly too simple: For example, you'll quickly appreciate adding something like:

     

    if ((pos > 0) && (character == DELETE)) {     pos--;

         print_string ("\b \b");

      }

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