#include "i2c.h"

void init_i2c(void) {
  // Initialize the control A register
  TWI0.CTRLA = TWI_INPUTLVL_I2C_gc    // I2C voltage transition level
               | TWI_SDASETUP_4CYC_gc // Four clock cycles setup time
               | TWI_SDAHOLD_50NS_gc  // 50ns SDA hold time
               | TWI_FMPEN_OFF_gc     // Standard SPI timing
      ;

  // The device's slave address
  TWI0.SADDR = 0x42;

  // Enable acting as a slave
  TWI0.SCTRLA = TWI_DIEN_bm     // Enable data interrupt
                | TWI_PIEN_bm   // Enable stop flag interrupt
                | TWI_SMEN_bm   // Enable smart mode
                | TWI_ENABLE_bm // Enable acting as a slave
      ;
}

// TODO: Figure out which interrupt does what

// Interrupt vector
ISR(TWI0_TWIS_vect) {
    asm('nop');
}

// Interrupt vector
ISR(TWI0_TWIM_vect) {
    asm('nop');
}