update lookup table example

Chapter11/compile_time/.clang-tidy

@@ -9,6 +9,7 @@ Checks: >
   -performance-no-int-to-ptr,
   portability-*,
   readability-*,
+  -readability-identifier-length
   readability-identifier-naming
 
 CheckOptions:

Chapter11/compile_time/CMakeLists.txt

@@ -86,7 +86,9 @@ include_directories(
   ${CMAKE_SOURCE_DIR}/hal/uart/inc
   ${CMAKE_SOURCE_DIR}/hal/inc
   ${CMAKE_SOURCE_DIR}/hal/gpio/inc
+  ${CMAKE_SOURCE_DIR}/hal/adc/inc
   ${CMAKE_SOURCE_DIR}/cstdlib_support
+  ${CMAKE_SOURCE_DIR}/util/inc
   )
 
 set(EXECUTABLE ${PROJECT_NAME}.elf)
@@ -108,7 +110,9 @@ add_executable(
   hal/uart/src/uart_stm32.cpp
   hal/gpio/src/gpio.cpp
   hal/gpio/src/gpio_interrupt_manager.cpp
+  hal/adc/src/adc_stm32.cpp
   cstdlib_support/retarget.cpp
+  util/src/units.cpp
   ${MAIN_CPP_PATH}/${MAIN_CPP_FILE_NAME}
   )
 

Chapter11/compile_time/app/src/main_lookup_table.cpp

@@ -4,69 +4,31 @@
 #include <stm32f072xb.h>
 
 #include <hal.hpp>
+#include <units.hpp>
 #include <uart_stm32.hpp>
+#include <adc_stm32.hpp>
 
 #include <retarget.hpp>
+#include <signal.hpp>
 
 #include <algorithm>
 #include <array>
 
-#include <gpio_stm32.hpp>
-
-ADC_HandleTypeDef hadc;
-
-static void MX_ADC_Init(void)
-{
-
-  /* USER CODE BEGIN ADC_Init 0 */
-
-  /* USER CODE END ADC_Init 0 */
-
-  ADC_ChannelConfTypeDef sConfig = {0};
-
-  /* USER CODE BEGIN ADC_Init 1 */
-
-  /* USER CODE END ADC_Init 1 */
-
-  /** Configure the global features of the ADC (Clock, Resolution, Data Alignment and number of conversion)
-  */
-  hadc.Instance = ADC1;
-  hadc.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV1;
-  hadc.Init.Resolution = ADC_RESOLUTION_12B;
-  hadc.Init.DataAlign = ADC_DATAALIGN_RIGHT;
-  hadc.Init.ScanConvMode = ADC_SCAN_DIRECTION_FORWARD;
-  hadc.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
-  hadc.Init.LowPowerAutoWait = DISABLE;
-  hadc.Init.LowPowerAutoPowerOff = DISABLE;
-  hadc.Init.ContinuousConvMode = DISABLE;
-  hadc.Init.DiscontinuousConvMode = DISABLE;
-  hadc.Init.ExternalTrigConv = ADC_SOFTWARE_START;
-  hadc.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
-  hadc.Init.DMAContinuousRequests = DISABLE;
-  hadc.Init.Overrun = ADC_OVR_DATA_PRESERVED;
-  if (HAL_ADC_Init(&hadc) != HAL_OK)
-  {
-    //Error_Handler();
-  }
-
-  /** Configure for the selected ADC regular channel to be converted.
-  */
-  sConfig.Channel = ADC_CHANNEL_0;
-  sConfig.Rank = ADC_RANK_CHANNEL_NUMBER;
-  sConfig.SamplingTime = ADC_SAMPLETIME_1CYCLE_5;
-  if (HAL_ADC_ConfigChannel(&hadc, &sConfig) != HAL_OK)
-  {
-    //Error_Handler();
-  }
-  /* USER CODE BEGIN ADC_Init 2 */
-
-  /* USER CODE END ADC_Init 2 */
-
-}
+namespace {
+    struct voltage_divider {
+        units::resistance r2; 
+        units::voltage vcc;
 
+        units::resistance get_r1(units::voltage vadc) {
+            return r2 * (vcc/vadc - 1);
+        }
+    };
+};
 
 int main()
 {
+    using namespace units;
+
     hal::init();
 
     hal::uart_stm32 uart(USART2);
@@ -74,28 +36,58 @@ int main()
 
     retarget::set_stdio_uart(&uart);
 
-    MX_ADC_Init();
+    hal::adc_stm32 adc(3.3_V);
+    adc.init();
+
+    constexpr float A = 1.18090254918130e-3;
+    constexpr float B = 2.16884014794388e-4;
+    constexpr float C = 1.90058756197216e-6;
+    constexpr float D = 1.83161892641824e-8;
+
+    constexpr int c_lut_points = 50;
+
+    constexpr signal<float, c_lut_points> resistance(1e3, 10e3);
+
+    constexpr auto temperature_k = 1 / (A +
+                                        B * signal(resistance, [](float x)
+                                                 { return std::log(x); }) +
+                                        C * signal(resistance, [](float x)
+                                                 { return std::pow(std::log(x), 2); }) +
+                                        D * signal(resistance, [](float x)
+                                                 { return std::pow(std::log(x), 3); }));
+
+    constexpr auto temperature_celsius = temperature_k - 273.15;
+
+    voltage_divider divider{10e3_Ohm, 3.3_V};
     
-
-    const hal::gpio_stm32<hal::port_a> button1(hal::pin::p4, [](){
-        printf("Button1 pressed!\r\n");
-    });
-
-    const hal::gpio_stm32<hal::port_a> button2(hal::pin::p5, [](){
-        printf("Button2 pressed!\r\n");
-    });
-    
-
     while(true)
     {
-        HAL_ADC_Start(&hadc);
-        HAL_ADC_PollForConversion(&hadc, 1000);
+        auto adc_val = adc.get_reading();
+        if(adc_val) {
+            auto adc_val_voltage = *adc_val;
+            auto thermistor_r = divider.get_r1(adc_val_voltage);
 
-        auto adc_val = HAL_ADC_GetValue(&hadc);
-        float mv = 3.3f * static_cast<float>(adc_val) / 4096.f;
-        printf("%d, %.2f\r\n", adc_val, mv);
-        hal::time::delay_ms(1000);
+            auto it = std::lower_bound(resistance.begin(), resistance.end(), thermistor_r.get());
+            
+            if(it != resistance.end()) {
+
+              std::size_t pos = std::distance(resistance.begin(), it);
+              float temperature = temperature_celsius.at(pos);
+
+              printf("%d mV, %d Ohm, %d.%d C\r\n", static_cast<int>(adc_val_voltage.get_mili()),
+                                        static_cast<int>(thermistor_r.get()),
+                                        static_cast<int>(temperature),
+                                        static_cast<int>(10*(temperature-std::floor(temperature)))
+                                        ); 
+            }
+        }
+        hal::time::delay_ms(200);
     }
 }
 
-// adc FeedVoltageSampleToChannel 0 3100 10
+// adc FeedVoltageSampleToChannel 0 3000 3 -> 1001 Ohm
+// adc FeedVoltageSampleToChannel 0 2800 3 -> 1787 Ohm
+// adc FeedVoltageSampleToChannel 0 2400 3 -> 3754 Ohm
+// adc FeedVoltageSampleToChannel 0 2200 3 -> 5003 Ohm
+// adc FeedVoltageSampleToChannel 0 2000 3 -> 6502 Ohm
+// adc FeedVoltageSampleToChannel 0 1700 3 -> 9412 Ohm

Chapter11/compile_time/hal/adc/inc/adc.hpp

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <expected>
+
+#include <units.hpp>
+
+namespace hal
+{
+    class adc {
+    public:
+        enum class error {
+            timeout
+        };
+
+        virtual void init() = 0;
+        virtual std::expected<units::voltage, adc::error> get_reading() = 0;
+    };
+};

Chapter11/compile_time/hal/adc/inc/adc_stm32.hpp

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <adc.hpp>
+#include <units.hpp>
+
+#include <stm32f0xx_hal.h>
+#include <stm32f072xb.h>
+
+namespace hal 
+{
+
+    class adc_stm32 : public adc{
+    public:
+        adc_stm32(units::voltage ref_voltage) : ref_voltage_(ref_voltage) {}
+
+        void init() override;
+        std::expected<units::voltage, adc::error> get_reading() override;
+    private:
+        ADC_HandleTypeDef adc_handle_;
+        units::voltage ref_voltage_;
+    };
+};

Chapter11/compile_time/hal/adc/src/adc_stm32.cpp

@@ -0,0 +1,47 @@
+#include <adc_stm32.hpp>
+
+void hal::adc_stm32::init() {
+    ADC_ChannelConfTypeDef sConfig = {0};
+
+    /** Configure the global features of the ADC (Clock, Resolution, Data Alignment and number of conversion)
+    */
+    adc_handle_.Instance = ADC1;
+    adc_handle_.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV1;
+    adc_handle_.Init.Resolution = ADC_RESOLUTION_12B;
+    adc_handle_.Init.DataAlign = ADC_DATAALIGN_RIGHT;
+    adc_handle_.Init.ScanConvMode = ADC_SCAN_DIRECTION_FORWARD;
+    adc_handle_.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
+    adc_handle_.Init.LowPowerAutoWait = DISABLE;
+    adc_handle_.Init.LowPowerAutoPowerOff = DISABLE;
+    adc_handle_.Init.ContinuousConvMode = DISABLE;
+    adc_handle_.Init.DiscontinuousConvMode = DISABLE;
+    adc_handle_.Init.ExternalTrigConv = ADC_SOFTWARE_START;
+    adc_handle_.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
+    adc_handle_.Init.DMAContinuousRequests = DISABLE;
+    adc_handle_.Init.Overrun = ADC_OVR_DATA_PRESERVED;
+    if (HAL_ADC_Init(&adc_handle_) != HAL_OK)
+    {
+        //Error_Handler();
+    }
+
+    /** Configure for the selected ADC regular channel to be converted.
+    */
+    sConfig.Channel = ADC_CHANNEL_0;
+    sConfig.Rank = ADC_RANK_CHANNEL_NUMBER;
+    sConfig.SamplingTime = ADC_SAMPLETIME_1CYCLE_5;
+    if (HAL_ADC_ConfigChannel(&adc_handle_, &sConfig) != HAL_OK)
+    {
+        //Error_Handler();
+    }
+}
+        
+std::expected<units::voltage, hal::adc::error> hal::adc_stm32::get_reading() {
+    HAL_ADC_Start(&adc_handle_);
+    if(HAL_ADC_PollForConversion(&adc_handle_, 1000) != HAL_OK) {
+        return std::unexpected(hal::adc::error::timeout);
+    }
+
+    auto adc_val = HAL_ADC_GetValue(&adc_handle_);
+
+    return ref_voltage_ * adc_val / 4096.f;
+}

Chapter11/compile_time/hal/gpio/inc/gpio.hpp

@@ -3,8 +3,6 @@
 #include <cstdint>
 #include <functional>
 
-//#include <gpio_interrupt_handler.hpp>
-
 namespace hal
 {
 class gpio

Chapter11/compile_time/util/inc/signal.hpp

@@ -0,0 +1,102 @@
+#pragma once
+
+#include <array>
+#include <cmath>
+
+template <typename T, std::size_t N>
+struct signal : public std::array<T, N>
+{
+
+  constexpr signal() {}
+
+  constexpr signal(T begin, T end)
+  {
+    static_assert(N > 1, "N must be bigger than 1");	  
+    float step = (end - begin) / (N - 1);
+
+    for (std::size_t i = 0; i < N; i++)
+    {
+      this->at(i) = begin + i * step;
+    }
+  }
+
+  constexpr signal(const std::array<T, N> &x, auto fun)
+  {
+    for (std::size_t i = 0; i < N; i++)
+    {
+      this->at(i) = fun(x.at(i));
+    }
+  }
+
+  constexpr signal(const signal &sig, auto fun)
+  {
+    for (std::size_t i = 0; i < N; i++)
+    {
+      this->at(i) = fun(sig.at(i));
+    }
+  }
+
+  constexpr signal operator+(const T &t) const
+  {
+    return signal(*this, [&](T elem)
+                  { return elem + t; });
+  };
+
+  constexpr signal operator-(const T &t) const
+  {
+    return signal(*this, [&](T elem)
+                  { return elem - t; });
+  };
+
+  constexpr signal operator*(const T &t) const
+  {
+    return signal(*this, [&](T elem)
+                  { return elem * t; });
+  };
+
+  constexpr signal operator/(const T &t) const
+  {
+    return signal(*this, [&](T elem)
+                  { return elem / t; });
+  };
+
+  constexpr signal operator+(const signal &sig) const
+  {
+    signal ret;
+    for (std::size_t i = 0; i < N; i++)
+    {
+      ret.at(i) = this->at(i) + sig.at(i);
+    }
+    return ret;
+  };
+
+  constexpr signal operator-(const signal &sig) const
+  {
+    signal ret;
+    for (std::size_t i = 0; i < N; i++)
+    {
+      ret.at(i) = this->at(i) - sig.at(i);
+    }
+    return ret;
+  };
+
+  friend constexpr signal operator+(const T &t, const signal &sig)
+  {
+    return sig + t;
+  }
+
+  friend constexpr signal operator*(const T &t, const signal &sig)
+  {
+    return sig * t;
+  }
+
+  friend constexpr signal operator/(const T &t, const signal &sig)
+  {
+    signal ret;
+    for (std::size_t i = 0; i < N; i++)
+    {
+      ret.at(i) = t / sig.at(i);
+    }
+    return ret;
+  }
+};

Chapter11/compile_time/util/inc/units.hpp

@@ -0,0 +1,33 @@
+#pragma once
+
+namespace units 
+{
+    template<typename T, typename ST>
+    class unit {
+    private:
+	    T val_; 
+    public:
+	    explicit unit(T val) : val_(val){}
+	    [[nodiscard]] T get() const {return val_;}
+        [[nodiscard]] T get_mili() const {return 1e3 * val_;}
+
+        constexpr T operator/(const unit& second) const{
+            return val_ / second.get();
+        }
+
+        constexpr unit operator*(const T& second) const{
+            return unit(val_ * second);
+        }
+
+        constexpr unit operator/(const T& second) const{
+            return unit(val_ / second);
+        }
+    };
+
+    using voltage = unit<float, struct the_voltage>;
+    using resistance = unit<float, struct the_resistance>;
+
+    voltage operator""_V(long double volts);
+
+    resistance operator""_Ohm(long double ohms);
+};

Chapter11/compile_time/util/src/units.cpp

@@ -0,0 +1,11 @@
+#include <units.hpp>
+
+namespace units {
+voltage operator""_V(long double volts) {
+    return voltage(static_cast<float>(volts));
+}
+
+resistance operator""_Ohm(long double ohms) {
+    return resistance(static_cast<float>(ohms));
+}
+};