#include <Wire.h>
#include "defines.h"

#define INA219_I2C_ADDRESS 0x40

bool is_device_available(uint8_t address)
{
  Wire.beginTransmission(address);
  uint8_t error = Wire.endTransmission();

  return (error == 0);
}

void wait_for_device(uint8_t i2c_device_address) {
  while (!is_device_available(i2c_device_address));
}

void eeprom_write_byte(uint8_t i2c_device_address, uint8_t eeprom_data_address, uint8_t data) {
  Wire.beginTransmission(i2c_device_address);
  Wire.write((uint8_t)(eeprom_data_address)); //writes the LSB
  Wire.write(data);
  Wire.endTransmission();
  wait_for_device(i2c_device_address);
}

byte eeprom_read_byte(uint8_t i2c_device_address, uint8_t eeprom_data_address) {
  uint8_t rdata = 0xFF;

  Wire.beginTransmission(i2c_device_address);
  Wire.write((uint8_t)(eeprom_data_address >> 8)); //writes the LSB
  Wire.endTransmission();
  Wire.requestFrom(i2c_device_address, (uint8_t)1);
  if (Wire.available()) {
    rdata = Wire.read();
  }
  return rdata;
}

void setup()
{
  Wire.begin(8, 10);

  Serial.begin(9600);
  while (!Serial);

  if (!is_device_available(INA219_I2C_ADDRESS))
  {
    Serial.println("No device was found");
    while (true);
  }
}

void loop()
{
  byte data[2];
  uint16_t value = 0;
  int16_t value_int = 0;

  eeprom_write_byte(INA219_I2C_ADDRESS, INA219_CALIBRATION_REG,0X10);
  eeprom_write_byte(INA219_I2C_ADDRESS, INA219_CALIBRATION_REG,0X60); 
  data[0] = eeprom_read_byte(INA219_I2C_ADDRESS, INA219_CALIBRATION_REG); 
  data[1] = eeprom_read_byte(INA219_I2C_ADDRESS, INA219_CALIBRATION_REG); 
  value = (uint16_t)((data[0] << 8) | data[1]); 
  printf("---------------------\n\r"); 
  printf("CALIBRATION REG = 0x%x\n\r",value); 

  data[0] = eeprom_read_byte(INA219_I2C_ADDRESS, INA219_BUSV_REG); 
  data[1] = eeprom_read_byte(INA219_I2C_ADDRESS, INA219_BUSV_REG); 
  value = (uint16_t)((data[0] << 8) | data[1]); 
  printf("Voltage = 0x%x ->> %i mV\n\r",value,value); 

  data[0] = eeprom_read_byte(INA219_I2C_ADDRESS, INA219_CURRENT_REG); 
  data[1] = eeprom_read_byte(INA219_I2C_ADDRESS, INA219_CURRENT_REG); 
  value = (uint16_t)((data[0] << 8) | data[1]); 
  printf("Current = 0x%x ->> %i mA\n\r",value,value); 

  data[0] = eeprom_read_byte(INA219_I2C_ADDRESS, INA219_POWER_REG); 
  data[1] = eeprom_read_byte(INA219_I2C_ADDRESS, INA219_POWER_REG); 
  value = (uint16_t)((data[0] << 8) | data[1]); 
  printf("Power = 0x%x ->> %i mW\n\r",value,value); 

  data[0] = eeprom_read_byte(INA219_I2C_ADDRESS, INA219_SHUNTV_REG); 
  data[1] = eeprom_read_byte(INA219_I2C_ADDRESS, INA219_SHUNTV_REG); 
  value = (uint16_t)((data[0] << 8) | data[1]); 
  printf("Shunt = 0x%x ->> %i mV\n\r",value,value); 

  delay(5000);
}