Colony

/* I2C.c

    I2C Communication

    Problem switching into slave mode. So never run as a slave otherwise you will never be able

        to speak again (unless a master tells you to).

*/

#include "i2c.h"

/*

int main(void) {

        i2c_test();

}

*/

//Call this to start I2C up

void i2c_init(void) {

  //Start off in slave mode so you can catch any data that comes your way

  //USI_TWI_Slave_Initialise(0x02);

  //Can't ever be a slave otherwise you will die. Stay as master and never give it up.

    USI_TWI_Master_Initialise();

}

//Call this to send a packet. *data is a char array of data_size. Make sure you put in data_size or we won't send

//everything.

//Note, mainboard is addr = 0x01.

void i2c_putpacket(char addr, char *data, char data_size) {

  //The packet that we will transmit over I2C

  unsigned char packet[data_size + 1];

  //First byte is the destination address + R/W (R = 1, W = 0)

  packet[0] = addr << 1;    //Shift the address over 1 bit, LSB is 0 which means write

  //Put data into packet

  for (int i = 0; i < data_size; i++) {

    packet[i+1] = data[i];

  }

  PORTB&=~_BV(PB4);

  //Send packet. Will open line, transmit, and close line.

  USI_TWI_Start_Transceiver_With_Data(packet, (data_size + 1));

  PORTB&=~_BV(PB5);

}

int i2c_getpacket(char *c) {

  if (USI_TWI_Data_In_Receive_Buffer()) {

    *c =  USI_TWI_Receive_Byte();

    return 0;

  } else{

      return -1;

  }

}

void delay_ms(int ms) 

{

        for(; ms > 15; ms-=15)

                _delay_ms(15);

        _delay_ms(ms);

}

// Note this will fail. You need to fix the switch from slave -> master before it will succeed.

void i2c_test(void) {

    char datatx[] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};

   char datarx;

  DDRA = _BV(PA3) | _BV(PA4) | _BV(PA5) | _BV(PA6) | _BV(PA7);

  PORTA = 0;

  PORTA |= _BV(PA3);

  //delay_ms(1000);

  sei();

  i2c_init();

    while(1) {

        delay_ms(1000);

    i2c_putpacket(0x01, datatx, 26);

        }

  /*

    while(1) {

      i2c_getpacket(&datarx);

      switch (datarx) {

        case 'a':

            PORTA |= _BV(PA4);

            break;

        case 'b':

            PORTA |= _BV(PA5);

            break;

        case 'c':

            PORTA |= _BV(PA6);

            break;

        case 'd':

            PORTA |= _BV(PA7);

            break;

      }

      if (datarx == 'd')

        break;

  }

   PORTA = 0;

  //PORTA |= _BV(PA5);

  delay_ms(1000);

  i2c_putpacket(0x01, datatx, 26);

  */

}