Merge pull request #7 from robamu-org/mueller/temp-sensor

added temperature sensor module

src/lib.rs

@@ -2,3 +2,4 @@
 
 pub mod button;
 pub mod leds;
+pub mod temp_sensor;

src/temp_sensor.rs

@@ -0,0 +1,81 @@
+//! # API for the On-Board Analog Devices ADT75 temperature sensor
+//!
+//! [Datasheet](https://www.analog.com/media/en/technical-documentation/data-sheets/ADT75.pdf)
+//!
+//! ## Examples
+//!
+//! - [Temperature Sensor example](https://github.com/robamu-org/vorago-reb1-rs/blob/main/examples/temp-sensor.rs)
+use cortex_m::prelude::_embedded_hal_blocking_i2c_Write;
+use embedded_hal::blocking::i2c::{Read, SevenBitAddress};
+use va108xx_hal::{
+    i2c::{Error, I2cMaster, I2cSpeed, MasterConfig},
+    pac::{I2CA, SYSCONFIG},
+    time::Hertz,
+};
+
+const ADT75_I2C_ADDR: u8 = 0b1001000;
+
+pub struct Adt75TempSensor {
+    sensor_if: I2cMaster<I2CA, SevenBitAddress>,
+    cmd_buf: [u8; 1],
+    current_reg: RegAddresses,
+}
+
+#[derive(PartialEq, Debug, Copy, Clone)]
+pub enum RegAddresses {
+    Temperature = 0x00,
+    Configuration = 0x01,
+    THystSetpoint = 0x02,
+    TOsSetPoint = 0x03,
+    OneShot = 0x04,
+}
+
+impl Adt75TempSensor {
+    pub fn new(
+        i2ca: I2CA,
+        sys_clk: impl Into<Hertz> + Copy,
+        sys_cfg: Option<&mut SYSCONFIG>,
+    ) -> Result<Self, Error> {
+        let mut sensor = Adt75TempSensor {
+            sensor_if: I2cMaster::i2ca(
+                i2ca,
+                MasterConfig::default(),
+                sys_clk,
+                I2cSpeed::Regular100khz,
+                sys_cfg,
+            ),
+            cmd_buf: [RegAddresses::Temperature as u8],
+            current_reg: RegAddresses::Temperature,
+        };
+        sensor.select_reg(RegAddresses::Temperature)?;
+        Ok(sensor)
+    }
+
+    pub fn select_reg(&mut self, reg: RegAddresses) -> Result<(), Error> {
+        if reg != self.current_reg {
+            self.cmd_buf[0] = reg as u8;
+            self.current_reg = reg;
+            self.sensor_if.write(ADT75_I2C_ADDR, &self.cmd_buf[0..1])?;
+        }
+        Ok(())
+    }
+
+    pub fn read_temperature(&mut self) -> Result<f32, Error> {
+        if self.current_reg != RegAddresses::Temperature {
+            self.select_reg(RegAddresses::Temperature)?;
+        }
+        let mut reply: [u8; 2] = [0; 2];
+        self.sensor_if.read(ADT75_I2C_ADDR, &mut reply)?;
+        let adc_code = (((reply[0] as u16) << 8) | reply[1] as u16) >> 4;
+        let temp_celcius: f32;
+        if ((adc_code >> 11) & 0x01) == 0 {
+            // Sign bit not set, positiv value
+            // Divide ADC code by 16 according to datasheet
+            temp_celcius = adc_code as f32 / 16.0;
+        } else {
+            // Calculation for negative values, assuming all 12 bits are used
+            temp_celcius = (adc_code - 4096) as f32 / 16.0;
+        }
+        Ok(temp_celcius)
+    }
+}