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#![allow(dead_code)]
extern crate i2cdev;
extern crate i2csensors;
extern crate byteorder;
use i2csensors::{Barometer,Thermometer};
use std::thread;
use std::time::Duration;
use std::error::Error;
use i2cdev::core::I2CDevice;
use byteorder::{ByteOrder, BigEndian};
pub const BMP180_I2C_ADDR: u16 = 0x77;
pub const BMP180_REGISTER_CTL: u8 = 0xF4;
pub const BMP180_CMD_TEMP: u8 = 0x2E;
pub const BMP180_REGISTER_TEMP_MSB: u8 = 0xF6;
pub const BMP180_CMD_PRESSURE: u8 = 0x34;
pub const BMP180_REGISTER_PRESSURE_MSB: u8 = 0xF6;
pub const BMP180_REGISTER_AC1MSB: u8 = 0xaa;
#[derive(Copy,Clone)]
pub enum BMP180PressureMode {
BMP180UltraLowPower,
BMP180Standard,
BMP180HighResolution,
BMP180UltraHighResolution,
}
impl BMP180PressureMode {
pub fn get_mode_value(self) -> u8 {
match self {
BMP180PressureMode::BMP180UltraLowPower => 0,
BMP180PressureMode::BMP180Standard => 1,
BMP180PressureMode::BMP180HighResolution => 2,
BMP180PressureMode::BMP180UltraHighResolution => 3,
}
}
pub fn mode_delay(self) -> Duration {
match self {
BMP180PressureMode::BMP180UltraLowPower => Duration::from_millis(5),
BMP180PressureMode::BMP180Standard => Duration::from_millis(8),
BMP180PressureMode::BMP180HighResolution => Duration::from_millis(14),
BMP180PressureMode::BMP180UltraHighResolution => Duration::from_millis(26),
}
}
}
#[derive(Copy,Clone)]
pub struct BMP180CalibrationCoefficients {
ac1: i16,
ac2: i16,
ac3: i16,
ac4: u16,
ac5: u16,
ac6: u16,
b1: i16,
b2: i16,
mb: i16,
mc: i16,
md: i16,
}
#[derive(Debug)]
pub struct BMP180RawReading {
padc: i32,
tadc: i16,
}
#[derive(Copy,Clone)]
pub struct BMP180BarometerThermometer<T: I2CDevice + Sized> {
pub i2cdev: T,
pub coeff: BMP180CalibrationCoefficients,
pub pressure_precision: BMP180PressureMode,
}
impl<T> BMP180BarometerThermometer<T>
where T: I2CDevice + Sized
{
pub fn new(mut i2cdev: T, pressure_precision: BMP180PressureMode) -> Result<BMP180BarometerThermometer<T>, T::Error> {
let coeff = try!(BMP180CalibrationCoefficients::new(&mut i2cdev));
Ok(BMP180BarometerThermometer {
i2cdev: i2cdev,
coeff: coeff,
pressure_precision: pressure_precision,
})
}
pub fn pressure_pa(&mut self) -> Result<f32, T::Error> {
let reading = try!(BMP180RawReading::new(&mut self.i2cdev, self.pressure_precision));
let b5 = self.coeff.calculate_b5(reading.tadc);
let real_pressure = calculate_real_pressure(reading.padc, b5, self.coeff, self.pressure_precision);
Ok(real_pressure as f32)
}
pub fn pressure_hpa(&mut self) -> Result<f32, T::Error> {
match self.pressure_pa() {
Ok(x) => Ok(x / 100_f32),
Err(e) => Err(e),
}
}
}
impl BMP180RawReading {
pub fn new<E: Error>(i2cdev: &mut I2CDevice<Error = E>, mode: BMP180PressureMode) -> Result<BMP180RawReading, E> {
try!(i2cdev.smbus_write_byte_data(BMP180_REGISTER_CTL, BMP180_CMD_TEMP));
thread::sleep(Duration::from_millis(5));
let mut buf = [0_u8; 2];
try!(i2cdev.write(&[BMP180_REGISTER_TEMP_MSB]));
try!(i2cdev.read(&mut buf));
let tadc: i16 = BigEndian::read_i16(&buf[..]);
let offset = mode.get_mode_value();
let delay = mode.mode_delay();
try!(i2cdev.smbus_write_byte_data(BMP180_REGISTER_CTL, BMP180_CMD_PRESSURE + (offset << 6)));
thread::sleep(delay);
let mut p_buf = [0_u8; 3];
try!(i2cdev.write(&[BMP180_REGISTER_PRESSURE_MSB]));
try!(i2cdev.read(&mut p_buf));
let padc: i32 = (((p_buf[0] as i32) << 16) + ((p_buf[1] as i32) << 8) + (p_buf[2] as i32)) >> (8 - (offset as u8));
Ok(BMP180RawReading {
padc: padc,
tadc: tadc,
})
}
}
impl BMP180CalibrationCoefficients {
pub fn new<E: Error>(i2cdev: &mut I2CDevice<Error = E>) -> Result<BMP180CalibrationCoefficients, E> {
let mut buf: [u8; 22] = [0; 22];
try!(i2cdev.write(&[BMP180_REGISTER_AC1MSB]));
try!(i2cdev.read(&mut buf));
Ok(BMP180CalibrationCoefficients {
ac1: BigEndian::read_i16(&buf[0..2]),
ac2: BigEndian::read_i16(&buf[2..4]),
ac3: BigEndian::read_i16(&buf[4..6]),
ac4: BigEndian::read_u16(&buf[6..8]),
ac5: BigEndian::read_u16(&buf[8..10]),
ac6: BigEndian::read_u16(&buf[10..12]),
b1: BigEndian::read_i16(&buf[12..14]),
b2: BigEndian::read_i16(&buf[14..16]),
mb: BigEndian::read_i16(&buf[16..18]),
mc: BigEndian::read_i16(&buf[18..20]),
md: BigEndian::read_i16(&buf[20..22]),
})
}
fn calculate_b5(self, raw_temp: i16) -> i32 {
let x1 = (((raw_temp as i32) - (self.ac6 as i32)) * (self.ac5 as i32)) >> 15;
let x2 = ((self.mc as i32) << 11) / (x1 + (self.md as i32));
x1 + x2
}
}
impl<T> Thermometer for BMP180BarometerThermometer<T>
where T: I2CDevice + Sized
{
type Error = T::Error;
fn temperature_celsius(&mut self) -> Result<f32, T::Error> {
let reading = try!(BMP180RawReading::new(&mut self.i2cdev, self.pressure_precision));
let b5 = self.coeff.calculate_b5(reading.tadc);
let t = (b5 + 8) >> 4;
Ok((t as f32) / 10_f32)
}
}
impl<T> Barometer for BMP180BarometerThermometer<T>
where T: I2CDevice + Sized
{
type Error = T::Error;
fn pressure_kpa(&mut self) -> Result<f32, T::Error> {
match self.pressure_pa() {
Ok(x) => Ok(x / 1000_f32),
Err(e) => Err(e),
}
}
}
fn calculate_real_pressure(padc: i32, b5: i32, coeff: BMP180CalibrationCoefficients, oss: BMP180PressureMode) -> f32 {
let b6: i32 = b5 - 4000;
let mut x1: i32 = ((coeff.b2 as i32) * ((b6 * b6) / (2 << 11))) / (2 << 10);
let mut x2: i32 = ((coeff.ac2 as i32) * b6) >> 11;
let mut x3: i32 = x1 + x2;
let b3 = ((((coeff.ac1 as u32) * 4 + x3 as u32) << oss.get_mode_value()) + 2) >> 2;
x1 = ((coeff.ac3 as i32) * b6) >> 13;
x2 = ((coeff.b1 as i32) * ((b6 * b6) >> 12)) >> 16;
x3 = ((x1 + x2) + 2) >> 2;
let b4 = ((coeff.ac4 as u32) * (x3 as u32 + 32768)) >> 15;
let b7 = ((padc as u32 - b3 as u32) as u32) * (50000 >> oss.get_mode_value());
let mut p: i32;
if b7 < 0x80000000 {
p = ((b7 * 2) / b4) as i32;
} else {
p = ((b7 / b4) * 2) as i32;
}
x1 = ((p >> 8) * (p >> 8)) as i32;
x1 = (x1 * 3038) >> 16;
x2 = (-7357_i32 * p) >> 16;
(p + ((x1 + x2 + 3791) >> 4) as i32) as f32
}
#[cfg(test)]
mod tests {
use super::*;
use mock::MockI2CDevice;
pub const BMP180_REGISTER_PRESSURE_MSB_TEST: usize = 0x90;
macro_rules! assert_almost_eq {
($left:expr, $right:expr) => ({
match (&($left), &($right)) {
(left_val, right_val) => {
if (*left_val - *right_val).abs() > 0.0001 {
panic!("assertion failed: ({:?} != {:?})", *left_val, *right_val);
}
}
}
})
}
fn make_dev(mut i2cdev: MockI2CDevice) -> BMP180BarometerThermometer<MockI2CDevice> {
(&mut i2cdev.regmap).write_regs(BMP180_REGISTER_TEMP_MSB as usize, &[0x6c, 0xfa]);
(&mut i2cdev.regmap).write_regs(BMP180_REGISTER_AC1MSB as usize,
&[0x1, 0x98 , 0xff, 0xb8 , 0xc7, 0xd1 , 0x7f, 0xe5 , 0x7f, 0xf5 , 0x5a, 0x71 , 0x18, 0x2e , 0x0,
0x04 , 0x80, 0x0 , 0xdd, 0xf9 , 0xb, 0x34 ]);
(&mut i2cdev.regmap).write_regs(BMP180_REGISTER_PRESSURE_MSB_TEST, &[0x5d, 0x23, 0x0]);
BMP180BarometerThermometer::new(i2cdev, BMP180PressureMode::BMP180UltraLowPower).unwrap()
}
#[test]
fn test_calculate_real_pressure() {
let raw = BMP180RawReading {
tadc: 27898,
padc: 23843,
};
let b5 = 2399;
let test_coeff = BMP180CalibrationCoefficients {
ac1: 408,
ac2: -72,
ac3: -14383,
ac4: 32741,
ac5: 32757,
ac6: 23153,
b1: 6190,
b2: 4,
mb: -32768,
mc: -8711,
md: 2868,
};
let pressure = calculate_real_pressure(raw.padc,
b5,
test_coeff,
BMP180PressureMode::BMP180UltraLowPower);
assert_almost_eq!(pressure, 69964_f32);
}
}