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#![no_std]
mod reg;
use reg::*;
use core::fmt::Debug;
use embedded_hal as hal;
use hal::blocking::i2c::{Write, WriteRead};
use cast::f32;
#[derive(Debug)]
pub enum Error<E> {
I2c(E),
InvalidData,
UnsupportedChip,
}
#[derive(Copy,Clone,PartialEq)]
pub enum Mode {
Inactive,
Active,
TakingReading,
}
#[derive(Copy,Clone,PartialEq)]
pub enum PressureAlt {
Pressure,
Altitude,
}
pub struct MPL3115A2<I2C> {
i2c: I2C,
mode: Mode,
pa: PressureAlt,
}
impl<I2C, E> MPL3115A2<I2C>
where
I2C: WriteRead<Error = E> + Write<Error = E>,
E: Debug,
{
pub fn new(i2c: I2C, pa: PressureAlt) -> Result<Self, Error<E>> {
let mut dev = Self {
i2c,
mode: Mode::Inactive,
pa: pa,
};
if dev.get_device_id()? != DEVICE_ID {
return Err(Error::UnsupportedChip);
}
dev.write_reg(Register::PT_DATA_CFG,EVENT_FLAGS).map_err(Error::I2c)?;
dev.change_reading_type(pa)?;
Ok(dev)
}
pub fn destroy(self) -> I2C {
self.i2c
}
pub fn get_device_id(&mut self) -> Result<u8, Error<E>> {
self.read_reg(Register::WHO_AM_I).map_err(Error::I2c)
}
pub fn activate(&mut self) -> Result<(), Error<E>> {
self.reg_set_bits(Register::CTRL_REG1, DEVICE_EN).map_err(Error::I2c)?;
self.mode = Mode::Active;
Ok(())
}
pub fn deactivate(&mut self) -> Result<(), Error<E>> {
self.reg_reset_bits(Register::CTRL_REG1, DEVICE_EN).map_err(Error::I2c)?;
self.mode = Mode::Inactive;
Ok(())
}
pub fn change_reading_type(&mut self, pa: PressureAlt) -> Result<(), Error<E>> {
match pa {
PressureAlt::Altitude => {
self.reg_set_bits(Register::CTRL_REG1, ALT_EN).map_err(Error::I2c)?;
},
PressureAlt::Pressure => {
self.reg_reset_bits(Register::CTRL_REG1, ALT_EN).map_err(Error::I2c)?;
}
}
self.pa = pa;
Ok(())
}
pub fn take_one_pa_reading(&mut self) -> Result<f32, Error<E>> {
self.start_reading()?;
while ! self.check_pa_reading()? {
}
self.get_pa_reading()
}
pub fn take_one_temp_reading(&mut self) -> Result<f32, Error<E>> {
self.start_reading()?;
while ! self.check_temp_reading()? {
}
self.get_temp_reading()
}
pub fn start_reading(&mut self) -> Result<(), Error<E>> {
self.reg_reset_bits(Register::CTRL_REG1, ONE_SHOT).map_err(Error::I2c)?;
self.reg_set_bits(Register::CTRL_REG1, ONE_SHOT).map_err(Error::I2c)?;
self.mode = Mode::TakingReading;
Ok(())
}
pub fn check_pa_reading(&mut self) -> Result<bool, Error<E>> {
let status_reg = self.read_reg(Register::STATUS).map_err(Error::I2c)?;
Ok(status_reg & PDR != 0)
}
pub fn check_temp_reading(&mut self) -> Result<bool, Error<E>> {
let status_reg = self.read_reg(Register::STATUS).map_err(Error::I2c)?;
Ok(status_reg & TDR != 0)
}
pub fn get_pa_reading(&mut self) -> Result<f32, Error<E>> {
let mut buf = [0u8; 3];
self.read_regs(Register::OUT_P_MSB, &mut buf).map_err(Error::I2c)?;
self.mode = Mode::Active;
match self.pa {
PressureAlt::Altitude => {
let lsb = buf[2]>>4;
let tempcsb = f32(lsb)/16.0;
let int_buf = [buf[0], buf[1]];
let altitude = f32( i16::from_be_bytes(int_buf)) + tempcsb;
Ok(altitude)
},
PressureAlt::Pressure => {
let int_buf = [0u8, buf[0], buf[1], buf[2]];
let mut pressure_whole: u32 = u32::from_be_bytes(int_buf);
pressure_whole >>= 6;
buf[2] &= 0b0011_0000;
buf[2] >>= 4;
let pressure_decimal = f32(buf[2])/4.0;
let pressure = f32(pressure_whole) + pressure_decimal;
Ok(pressure)
}
}
}
pub fn get_temp_reading(&mut self) -> Result<f32, Error<E>> {
let mut buf = [0u8; 2];
self.read_regs(Register::OUT_T_MSB, &mut buf).map_err(Error::I2c)?;
self.mode = Mode::Active;
let mut neg_sign = false;
if buf[0] > 0x7F
{
let mut foo = u16::from_be_bytes(buf);
foo = !foo + 1;
buf = foo.to_be_bytes();
buf[1] = buf[1] & 0xF0;
neg_sign = true;
}
let templsb = f32(buf[1]>>4)/16.0;
let mut temperature = f32(buf[0]) + templsb;
if neg_sign {
temperature = 0.0 - temperature;
}
Ok(temperature)
}
pub fn set_oversample_rate(&mut self, mut sample_rate: u8) -> Result<(), Error<E>> {
if sample_rate > 7 {
sample_rate = 7;
}
sample_rate <<= 3;
let mut temp_setting = self.read_reg(Register::CTRL_REG1).map_err(Error::I2c)?;
temp_setting &= 0b1100_0111;
temp_setting |= sample_rate;
self.write_reg(Register::CTRL_REG1,temp_setting).map_err(Error::I2c)
}
#[inline]
fn read_reg(&mut self, reg: Register) -> Result<u8, E> {
let mut buf = [0u8];
self.i2c.write_read(I2C_SAD, &[reg.addr()], &mut buf)?;
Ok(buf[0])
}
#[inline]
fn read_regs(&mut self, reg: Register, buffer: &mut [u8]) -> Result<(), E> {
self.i2c
.write_read(I2C_SAD, &[reg.addr()], buffer)
}
#[inline]
fn write_reg(&mut self, reg: Register, val: u8) -> Result<(), E> {
self.i2c.write(I2C_SAD, &[reg.addr(), val])
}
#[inline]
fn modify_reg<F>(&mut self, reg: Register, f: F) -> Result<(), E>
where
F: FnOnce(u8) -> u8,
{
let r = self.read_reg(reg)?;
self.write_reg(reg, f(r))?;
Ok(())
}
#[inline]
fn reg_set_bits(&mut self, reg: Register, bits: u8) -> Result<(), E> {
self.modify_reg(reg, |v| v | bits)
}
#[inline]
fn reg_reset_bits(&mut self, reg: Register, bits: u8) -> Result<(), E> {
self.modify_reg(reg, |v| v & !bits)
}
#[inline]
fn reg_xset_bits(&mut self, reg: Register, bits: u8, set: bool) -> Result<(), E> {
if set {
self.reg_set_bits(reg, bits)
} else {
self.reg_reset_bits(reg, bits)
}
}
}