feat: add support for internal temperature sensor (tsens) for esp32c6 and esp32c3 (#2875)

* feat: add basic support for temperature sensor (tsens) for esp32c6

* feat: add basic support for temperature sensor (tsens) for esp32c3

* feat: add configurable clock source for temperature sensor

* feat: add Temperature struct to avoid enforcing usage of floats

- Also add misc derives to multiple structs
- Add power_up / power_down methods to TemperatureSensor
- Enable ApbSarAdc via PeripheralGuard

* fix: move tsens module to unstable module list

esp-hal/CHANGELOG.md

@@ -54,6 +54,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added `AnyPin::steal(pin_number)` (#2854)
 - `adc::{AdcCalSource, Attenuation, Resolution}` now implement `Hash` and `defmt::Format` (#2840)
 - `rtc_cntl::{RtcFastClock, RtcSlowClock, RtcCalSel}` now implement `PartialEq`, `Eq`, `Hash` and `defmt::Format` (#2840)
+- Added `tsens::TemperatureSensor` peripheral for ESP32C6 and ESP32C3 (#2875)
 
 ### Changed
 

esp-hal/src/lib.rs

@@ -267,6 +267,8 @@ unstable_module! {
     pub mod touch;
     #[cfg(trace0)]
     pub mod trace;
+    #[cfg(tsens)]
+    pub mod tsens;
     #[cfg(any(twai0, twai1))]
     pub mod twai;
     #[cfg(usb_device)]

esp-hal/src/soc/esp32c3/peripherals.rs

@@ -52,6 +52,7 @@ crate::peripherals! {
         SW_INTERRUPT <= virtual,
         TIMG0 <= TIMG0,
         TIMG1 <= TIMG1,
+        TSENS <= virtual,
         TWAI0 <= TWAI0,
         UART0 <= UART0,
         UART1 <= UART1,

esp-hal/src/soc/esp32c6/peripherals.rs

@@ -80,6 +80,7 @@ crate::peripherals! {
         TIMG0 <= TIMG0,
         TIMG1 <= TIMG1,
         TRACE0 <= TRACE,
+        TSENS <= virtual,
         TWAI0 <= TWAI0,
         TWAI1 <= TWAI1,
         UART0 <= UART0,

esp-hal/src/system.rs

@@ -132,6 +132,9 @@ pub enum Peripheral {
     /// Systimer peripheral.
     #[cfg(systimer)]
     Systimer,
+    /// Temperature sensor peripheral.
+    #[cfg(tsens)]
+    Tsens,
 }
 
 impl Peripheral {
@@ -398,6 +401,10 @@ impl PeripheralClockControl {
             Peripheral::Systimer => {
                 perip_clk_en0.modify(|_, w| w.systimer_clk_en().bit(enable));
             }
+            #[cfg(tsens)]
+            Peripheral::Tsens => {
+                perip_clk_en1.modify(|_, w| w.tsens_clk_en().bit(enable));
+            }
         }
     }
 
@@ -610,6 +617,16 @@ impl PeripheralClockControl {
                 perip_rst_en0.modify(|_, w| w.systimer_rst().set_bit());
                 perip_rst_en0.modify(|_, w| w.systimer_rst().clear_bit());
             }
+            #[cfg(all(tsens, esp32c6))]
+            Peripheral::Tsens => {
+                perip_rst_en0.modify(|_, w| w.tsens_rst().set_bit());
+                perip_rst_en0.modify(|_, w| w.tsens_rst().clear_bit());
+            }
+            #[cfg(all(tsens, esp32c3))]
+            Peripheral::Tsens => {
+                perip_rst_en1.modify(|_, w| w.tsens_rst().set_bit());
+                perip_rst_en1.modify(|_, w| w.tsens_rst().clear_bit());
+            }
         });
     }
 }
@@ -778,6 +795,16 @@ impl PeripheralClockControl {
                     .systimer_conf()
                     .modify(|_, w| w.systimer_clk_en().bit(enable));
             }
+            #[cfg(tsens)]
+            Peripheral::Tsens => {
+                system
+                    .tsens_clk_conf()
+                    .modify(|_, w| w.tsens_clk_en().bit(enable));
+
+                system
+                    .tsens_clk_conf()
+                    .modify(|_, w| w.tsens_clk_sel().bit(enable));
+            }
         }
     }
 
@@ -977,6 +1004,15 @@ impl PeripheralClockControl {
                     .systimer_conf()
                     .modify(|_, w| w.systimer_rst_en().clear_bit());
             }
+            #[cfg(tsens)]
+            Peripheral::Tsens => {
+                system
+                    .tsens_clk_conf()
+                    .modify(|_, w| w.tsens_rst_en().set_bit());
+                system
+                    .tsens_clk_conf()
+                    .modify(|_, w| w.tsens_rst_en().clear_bit());
+            }
         }
     }
 }

esp-hal/src/tsens.rs

@@ -0,0 +1,189 @@
+//! # Temperature Sensor (tsens)
+//!
+//! ## Overview
+//!
+//! The Temperature Sensor peripheral is used to measure the internal
+//! temperature inside the chip. The voltage is internally converted via an ADC
+//! into a digital value, and has a measuring range of –40 °C to 125 °C.
+//! The temperature value depends on factors like microcontroller clock
+//! frequency or I/O load. Generally, the chip’s internal temperature is higher
+//! than the operating ambient temperature.
+//!
+//! It is recommended to wait a few hundred microseconds after turning it on
+//! before measuring, in order to allow the sensor to stabilize.
+//!
+//! ## Configuration
+//!
+//! The temperature sensor can be configured with different clock sources.
+//!
+//! ## Examples
+//!
+//! The following example will measure the internal chip temperature every
+//! second, and print it
+//!
+//! ```rust, no_run
+#![doc = crate::before_snippet!()]
+//! # use esp_hal::tsens::{TemperatureSensor, Config};
+//! # use esp_hal::delay::Delay;
+//!
+//! let temperature_sensor = TemperatureSensor::new(
+//!         peripherals.TSENS,
+//!         Config::default()
+//!     ).unwrap();
+//! let delay = Delay::new();
+//! delay.delay_micros(200);
+//! loop {
+//!   let temp = temperature_sensor.get_temperature();
+//!   println!("Temperature: {:.2}°C", temp.to_celcius());
+//!   delay.delay_millis(1_000);
+//! }
+//! # }
+//! ```
+//! 
+//! ## Implementation State
+//!
+//! - Temperature calibration range is not supported
+//! - Interrupts are not supported
+
+use crate::{
+    peripheral::{Peripheral, PeripheralRef},
+    peripherals::TSENS,
+    system::GenericPeripheralGuard,
+};
+
+/// Clock source for the temperature sensor
+#[derive(Debug, Clone, Default, PartialEq, Eq, Copy, Hash)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub enum ClockSource {
+    /// Use RC_FAST clock source
+    RcFast,
+    /// Use XTAL clock source
+    #[default]
+    Xtal,
+}
+
+/// Temperature sensor configuration
+#[derive(Debug, Clone, Default, PartialEq, Eq, Copy, Hash, procmacros::BuilderLite)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[non_exhaustive]
+pub struct Config {
+    clock_source: ClockSource,
+}
+
+/// Temperature sensor configuration error
+#[derive(Debug, Clone, PartialEq, Eq, Copy, Hash)]
+#[non_exhaustive]
+pub enum ConfigError {}
+
+/// Temperature value
+/// This struct stores the raw ADC value, and can be used to calculate the
+/// temperature in Celsius using the formula:
+/// `(raw_value * 0.4386) - (offset * 27.88) - 20.52`
+#[derive(Debug)]
+pub struct Temperature {
+    /// Raw ADC value
+    pub raw_value: u8,
+
+    /// Offset value - depends on the temperature range configured
+    pub offset: i8,
+}
+
+impl Temperature {
+    /// Create a new temperature value
+    #[inline]
+    pub fn new(raw_value: u8, offset: i8) -> Self {
+        Self { raw_value, offset }
+    }
+
+    /// Get the temperature in Celsius
+    #[inline]
+    pub fn to_celsius(&self) -> f32 {
+        (self.raw_value as f32) * 0.4386 - (self.offset as f32) * 27.88 - 20.52
+    }
+
+    /// Get the temperature in Fahrenheit
+    #[inline]
+    pub fn to_fahrenheit(&self) -> f32 {
+        let celsius = self.to_celsius();
+        (celsius * 1.8) + 32.0
+    }
+
+    /// Get the temperature in Kelvin
+    #[inline]
+    pub fn to_kelvin(&self) -> f32 {
+        let celsius = self.to_celsius();
+        celsius + 273.15
+    }
+}
+
+/// Temperature sensor driver
+#[derive(Debug)]
+pub struct TemperatureSensor<'d> {
+    _peripheral: PeripheralRef<'d, TSENS>,
+    _tsens_guard: GenericPeripheralGuard<{ crate::system::Peripheral::Tsens as u8 }>,
+    _abp_saradc_guard: GenericPeripheralGuard<{ crate::system::Peripheral::ApbSarAdc as u8 }>,
+}
+
+impl<'d> TemperatureSensor<'d> {
+    /// Create a new temperature sensor instance with configuration
+    /// The sensor will be automatically powered up
+    pub fn new(
+        peripheral: impl Peripheral<P = TSENS> + 'd,
+        config: Config,
+    ) -> Result<Self, ConfigError> {
+        crate::into_ref!(peripheral);
+        // NOTE: We need enable ApbSarAdc before enabling Tsens
+        let apb_saradc_guard = GenericPeripheralGuard::new();
+        let tsens_guard = GenericPeripheralGuard::new();
+
+        let mut tsens = Self {
+            _peripheral: peripheral,
+            _tsens_guard: tsens_guard,
+            _abp_saradc_guard: apb_saradc_guard,
+        };
+        tsens.apply_config(&config)?;
+
+        tsens.power_up();
+
+        Ok(tsens)
+    }
+
+    /// Power up the temperature sensor
+    pub fn power_up(&self) {
+        debug!("Power up");
+        let abp_saradc = unsafe { &*crate::peripherals::APB_SARADC::PTR };
+        abp_saradc.tsens_ctrl().modify(|_, w| w.pu().set_bit());
+    }
+
+    /// Power down the temperature sensor - useful if you want to save power
+    pub fn power_down(&self) {
+        let abp_saradc = unsafe { &*crate::peripherals::APB_SARADC::PTR };
+        abp_saradc.tsens_ctrl().modify(|_, w| w.pu().clear_bit());
+    }
+
+    /// Change the temperature sensor configuration
+    pub fn apply_config(&mut self, config: &Config) -> Result<(), ConfigError> {
+        let apb_saradc = unsafe { &*crate::peripherals::APB_SARADC::PTR };
+
+        // Set clock source
+        apb_saradc.tsens_ctrl2().write(|w| {
+            w.clk_sel()
+                .bit(matches!(config.clock_source, ClockSource::Xtal))
+        });
+
+        Ok(())
+    }
+
+    /// Get the raw temperature value
+    #[inline]
+    pub fn get_temperature(&self) -> Temperature {
+        let abp_saradc = unsafe { &*crate::peripherals::APB_SARADC::PTR };
+
+        let raw_value = abp_saradc.tsens_ctrl().read().out().bits();
+
+        // TODO Address multiple temperature ranges and offsets
+        let offset = -1i8;
+
+        Temperature::new(raw_value, offset)
+    }
+}

esp-metadata/devices/esp32c3.toml

@@ -52,6 +52,7 @@ symbols = [
     "phy",
     "bt",
     "wifi",
+    "tsens",
 
     # ROM capabilities
     "rom_crc_le",

esp-metadata/devices/esp32c6.toml

@@ -83,6 +83,7 @@ symbols = [
     "wifi6",
     "ieee802154",
     "lp_core",
+    "tsens",
 
     # ROM capabilities
     "rom_crc_le",

qa-test/src/bin/temperature_sensor.rs

@@ -0,0 +1,33 @@
+//! This example uses the internal temperature sensor to measure the chip's
+//! temperature
+
+//% CHIPS: esp32c6 esp32c3
+
+#![no_std]
+#![no_main]
+
+use esp_backtrace as _;
+use esp_hal::{
+    delay::Delay,
+    entry,
+    tsens::{Config, TemperatureSensor},
+};
+use esp_println::println;
+
+#[entry]
+fn main() -> ! {
+    esp_println::logger::init_logger_from_env();
+    let peripherals = esp_hal::init(esp_hal::Config::default());
+
+    let temperature_sensor = TemperatureSensor::new(peripherals.TSENS, Config::default()).unwrap();
+    let delay = Delay::new();
+
+    // Wait for the sensor to stabilize
+    delay.delay_micros(200);
+
+    loop {
+        let temp = temperature_sensor.get_temperature();
+        println!("Temperature: {:.2}°C", temp.to_celsius());
+        delay.delay_millis(1_000);
+    }
+}