fix(temperature_sensor): Fix temperature sensor value accurency in high range variation

Author: mythbuster5

components/esp_driver_tsens/src/temperature_sensor.c

@@ -65,9 +65,18 @@ static esp_err_t temperature_sensor_choose_best_range(temperature_sensor_handle_
     for (int i = 0 ; i < TEMPERATURE_SENSOR_ATTR_RANGE_NUM; i++) {
         if ((tsens_config->range_min >= s_tsens_attribute_copy[i].range_min) && (tsens_config->range_max <= s_tsens_attribute_copy[i].range_max)) {
             tsens->tsens_attribute = &s_tsens_attribute_copy[i];
+            int original_idx = -1;
+            for (int j = 0; j < TEMPERATURE_SENSOR_ATTR_RANGE_NUM; j++) {
+                if (temperature_sensor_attributes[j].reg_val == s_tsens_attribute_copy[i].reg_val) {
+                    original_idx = j;
+                    break;
+                }
+            }
+            if (original_idx != -1) {
+                temp_sensor_sync_tsens_idx(original_idx);
+            }
             break;
         }
-        temp_sensor_sync_tsens_idx(i);
     }
     ESP_RETURN_ON_FALSE(tsens->tsens_attribute != NULL, ESP_ERR_INVALID_ARG, TAG, "Out of testing range");
     return ESP_OK;
@@ -166,6 +175,8 @@ esp_err_t temperature_sensor_install(const temperature_sensor_config_t *tsens_co
              tsens->tsens_attribute->range_max,
              tsens->tsens_attribute->error_max);
 
+    printf("tsens->tsens_attribute->reg_val: %d\n", tsens->tsens_attribute->reg_val);
+
     temperature_sensor_ll_set_range(tsens->tsens_attribute->reg_val);
 
     tsens->fsm = TEMP_SENSOR_FSM_INIT;

components/esp_hw_support/sar_periph_ctrl_common.c

@@ -9,6 +9,7 @@
 #include "freertos/FreeRTOS.h"
 #include "esp_private/sar_periph_ctrl.h"
 #include "esp_log.h"
+#include "esp_timer.h"
 
 #if SOC_TEMP_SENSOR_SUPPORTED
 #include "hal/temperature_sensor_ll.h"
@@ -40,17 +41,22 @@ static const char *TAG_TSENS = "temperature_sensor";
 # define SAR_PERIPH_CTRL_COMMON_FN_ATTR
 #endif
 
+#define TSENS_LINE_REGRESSION_US (200)
+
 static int s_record_min = INT_NOT_USED;
 static int s_record_max = INT_NOT_USED;
 static int s_temperature_sensor_power_cnt;
+static bool s_first_temp_read = false;
 
 static uint8_t s_tsens_idx = 2; // Index for temperature attribute, set 2(middle) as default value
+static int64_t timer1 = 0;
 
 void temperature_sensor_power_acquire(void)
 {
     esp_os_enter_critical(&rtc_spinlock);
     s_temperature_sensor_power_cnt++;
     if (s_temperature_sensor_power_cnt == 1) {
+        s_first_temp_read = true;
         regi2c_saradc_enable();
 #if !SOC_TSENS_IS_INDEPENDENT_FROM_ADC
         adc_apb_periph_claim();
@@ -60,6 +66,9 @@ void temperature_sensor_power_acquire(void)
             temperature_sensor_ll_reset_module();
         }
         temperature_sensor_ll_enable(true);
+        // Set the range as recorded.
+        temperature_sensor_ll_set_range(temperature_sensor_attributes[s_tsens_idx].reg_val);
+        timer1 = esp_timer_get_time();
     }
     esp_os_exit_critical(&rtc_spinlock);
 }
@@ -101,6 +110,18 @@ int16_t temp_sensor_get_raw_value(bool *range_changed)
 {
     esp_os_enter_critical(&rtc_spinlock);
 
+    // When this is the first time reading a value, check whether the time here minus the
+    // initialization time is greater than 200 microseconds (the time for linear regression).
+    // If it is less than 200 microseconds, continue waiting here.
+    if (s_first_temp_read == true) {
+        int64_t timer2 = esp_timer_get_time();
+        int64_t diff = timer2 - timer1;
+        if (diff < TSENS_LINE_REGRESSION_US) {
+            esp_rom_delay_us(TSENS_LINE_REGRESSION_US - diff);
+        }
+        s_first_temp_read = false;
+    }
+
     int degree = temperature_sensor_get_raw_value();
     uint8_t temperature_dac;