80 lines
2.5 KiB
Rust
80 lines
2.5 KiB
Rust
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//! # API for the On-Board Analog Devices ADT75 temperature sensor
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//!
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//! [Datasheet](https://www.analog.com/media/en/technical-documentation/data-sheets/ADT75.pdf)
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//!
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//! ## Examples
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//!
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//! - [Temperature Sensor example](https://egit.irs.uni-stuttgart.de/rust/vorago-reb1/src/branch/main/examples/adt75-temp-sensor.rs)
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use embedded_hal::i2c::{I2c, SevenBitAddress};
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use va108xx_hal::{
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i2c::{Error, I2cMaster, I2cSpeed, MasterConfig},
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pac,
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time::Hertz,
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};
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const ADT75_I2C_ADDR: u8 = 0b1001000;
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pub struct Adt75TempSensor {
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sensor_if: I2cMaster<pac::I2ca, SevenBitAddress>,
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cmd_buf: [u8; 1],
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current_reg: RegAddresses,
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}
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#[derive(PartialEq, Eq, Debug, Copy, Clone)]
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pub enum RegAddresses {
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Temperature = 0x00,
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Configuration = 0x01,
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THystSetpoint = 0x02,
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TOsSetPoint = 0x03,
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OneShot = 0x04,
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}
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impl Adt75TempSensor {
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pub fn new(
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i2ca: pac::I2ca,
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sys_clk: impl Into<Hertz> + Copy,
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sys_cfg: Option<&mut pac::Sysconfig>,
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) -> Result<Self, Error> {
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let mut sensor = Adt75TempSensor {
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sensor_if: I2cMaster::i2ca(
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i2ca,
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MasterConfig::default(),
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sys_clk,
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I2cSpeed::Regular100khz,
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sys_cfg,
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),
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cmd_buf: [RegAddresses::Temperature as u8],
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current_reg: RegAddresses::Temperature,
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};
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sensor.select_reg(RegAddresses::Temperature)?;
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Ok(sensor)
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}
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pub fn select_reg(&mut self, reg: RegAddresses) -> Result<(), Error> {
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if reg != self.current_reg {
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self.cmd_buf[0] = reg as u8;
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self.current_reg = reg;
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self.sensor_if.write(ADT75_I2C_ADDR, &self.cmd_buf[0..1])?;
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}
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Ok(())
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}
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pub fn read_temperature(&mut self) -> Result<f32, Error> {
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if self.current_reg != RegAddresses::Temperature {
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self.select_reg(RegAddresses::Temperature)?;
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}
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let mut reply: [u8; 2] = [0; 2];
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self.sensor_if.read(ADT75_I2C_ADDR, &mut reply)?;
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let adc_code = (((reply[0] as u16) << 8) | reply[1] as u16) >> 4;
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let temp_celcius: f32 = if ((adc_code >> 11) & 0x01) == 0 {
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// Sign bit not set, positiv value
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// Divide ADC code by 16 according to datasheet
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adc_code as f32 / 16.0
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} else {
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// Calculation for negative values, assuming all 12 bits are used
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(adc_code - 4096) as f32 / 16.0
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};
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Ok(temp_celcius)
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}
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}
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