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extern crate byteorder;
extern crate i2cdev;
use byteorder::{ByteOrder, BigEndian};
use i2cdev::core::{I2CDevice};
pub const INA219_ADDR: u8 = 0x41;
enum Register {
ShuntVoltage = 0x01,
BusVoltage = 0x02,
Power = 0x03,
Current = 0x04,
Calibration = 0x05
}
pub struct INA219<T: I2CDevice> {
device: T
}
impl<T> INA219<T> where T: I2CDevice {
pub fn new(device: T) -> INA219<T> {
INA219 { device: device }
}
pub fn calibrate(&mut self, values: &[u8]) -> Result<(), T::Error> {
let mut data = vec![Register::Calibration as u8];
data.extend(values.iter().cloned());
self.device.write(&mut data)?;
Ok(())
}
pub fn shunt_voltage(&mut self) -> Result<i16, T::Error> {
let value = self.read(Register::ShuntVoltage)?;
Ok(value as i16)
}
pub fn voltage(&mut self) -> Result<u16, T::Error> {
let value = self.read(Register::BusVoltage)?;
Ok((value >> 3) * 4)
}
pub fn power(&mut self) -> Result<i16, T::Error> {
let value = self.read(Register::Power)?;
Ok(value as i16)
}
pub fn current(&mut self) -> Result<i16, T::Error> {
let value = self.read(Register::Current)?;
Ok(value as i16)
}
fn read(&mut self, register: Register) -> Result<u16, T::Error> {
let mut buf: [u8; 2] = [0x00; 2];
self.device.smbus_write_byte(register as u8)?;
self.device.read(&mut buf)?;
Ok(BigEndian::read_u16(&buf))
}
}