Merge pull request #13 from Sensirion/add-read-measurement

Add read measurement

Author: LeonieFierz

CHANGELOG.md

@@ -5,18 +5,56 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased] 
 
+
+## [1.0.1] - 2025-2-1
+
+- add convenience method to read out measurements again
+
 ## [1.0.0] - 2025-1-30
 
 ### Added
 
 - All commands according to data sheet
-## [0.1.0] - 2021-2-1
+
+
+### Changed
+
+Note that there are breaking changes:
+- You need to call scd4x_init(SCD41_I2C_ADDR_62); before sending any command t
+- all methods that have been named xxxTicks are now named xxxRaw
+- getDataReadyFlag has been renamed to getDataReadyStatus
+- data type for parameter count in HAL implementation has been changed from uint16_t to uint8_t 
+- scd4x_set_ambient_pressure takes now a uint32_t in Pa and scd4x_set_ambient_pressure_raw takes a uint16_t in hPa
+- scd4x_get_ambient_pressure returns now a uint32_t in Pa and scd4x_get_ambient_pressure_raw returns a uint16_t in hPa
+- scd4x_get_automatic_self_calibration/scd4x_set_automatic_self_calibration has been renamed to scd4x_get_automatic_self_calibration_enabled/scd4x_set_automatic_self_calibration_enabled
+- signature of scd4x_get_serial_number has changed
+- removed read_measurement convenience method - see bugfix 1.0.1 where it is added again
+
+
+## [0.2.1] - 2021-04-30
+
+### Changed
+
+* Increase timing for single shot from 1350ms to 5000ms
+* Increase timing for self test from 5500ms to 10000ms
+
+
+## [0.2.0] - 2021-03-01
 
 ### Added
+- Convenience interfaces taking care of unit conversion to and from ticks.
+
+### Fixed
+- wake-up interface handles missing ACK from sensor on wake up.
+
+
+## [0.1.0] - 2021-01-28
+
+Initial release
 
-- Initial version
-- Check latest 0.x.x version for changelog prior to version 1.0.0
 
 [Unreleased]: https://github.com/Sensirion/embedded-i2c-scd4x/compare/1.0.0...HEAD
-[1.0.0]: https://github.com/Sensirion/embedded-i2c-scd4x/compare/0.1.0...1.0.0
-[0.1.0]: https://github.com/Sensirion/embedded-i2c-scd4x/releases/tag/0.1.0
+[1.0.0]: https://github.com/Sensirion/embedded-i2c-scd4x/compare/0.2.1...1.0.0
+[0.2.1]: https://github.com/Sensirion/embedded-i2c-scd4x/compare/0.2.0...0.2.1
+[0.2.0]: https://github.com/Sensirion/embedded-i2c-scd4x/compare/0.1.0...0.2.0
+[0.1.0]: https://github.com/Sensirion/embedded-i2c-scd4x/releases/tag/0.1.0

example-usage/scd4x_i2c_example_usage.c

@@ -99,8 +99,8 @@ int main(void) {
     //
     bool data_ready = false;
     uint16_t co2_concentration = 0;
-    uint16_t temperature = 0;
-    uint16_t relative_humidity = 0;
+    int32_t temperature = 0;
+    int32_t relative_humidity = 0;
     uint16_t repetition = 0;
     for (repetition = 0; repetition < 50; repetition++) {
         //
@@ -124,17 +124,17 @@ int main(void) {
                 continue;
             }
         }
-        error = scd4x_read_measurement_raw(&co2_concentration, &temperature,
-                                           &relative_humidity);
+        error = scd4x_read_measurement(&co2_concentration, &temperature,
+                                       &relative_humidity);
         if (error != NO_ERROR) {
-            printf("error executing read_measurement_raw(): %i\n", error);
+            printf("error executing read_measurement(): %i\n", error);
             continue;
         }
         //
         // Print results in physical units.
         printf("CO2 concentration [ppm]: %u\n", co2_concentration);
-        printf("Temperature ticks: %u\n", temperature);
-        printf("Humidity ticks: %u\n", relative_humidity);
+        printf("Temperature [m°C] : %i\n", temperature);
+        printf("Humidity [mRH]: %i\n", relative_humidity);
     }
 
     return NO_ERROR;

scd4x_i2c.c

@@ -159,6 +159,20 @@ int16_t scd4x_read_measurement_raw(uint16_t* co2_concentration,
     return local_error;
 }
 
+int16_t scd4x_read_measurement(uint16_t* co2, int32_t* temperature_m_deg_c,
+                               int32_t* humidity_m_percent_rh) {
+    int16_t error;
+    uint16_t temperature;
+    uint16_t humidity;
+    error = scd4x_read_measurement_raw(co2, &temperature, &humidity);
+    if (error) {
+        return error;
+    }
+    *temperature_m_deg_c = ((21875 * (int32_t)temperature) >> 13) - 45000;
+    *humidity_m_percent_rh = ((12500 * (int32_t)humidity) >> 13);
+    return NO_ERROR;
+}
+
 int16_t scd4x_stop_periodic_measurement() {
     int16_t local_error = NO_ERROR;
     uint8_t* buffer_ptr = communication_buffer;

scd4x_i2c.h

@@ -195,6 +195,21 @@ int16_t scd4x_read_measurement_raw(uint16_t* co2_concentration,
                                    uint16_t* temperature,
                                    uint16_t* relative_humidity);
 
+/**
+ * @brief Read sensor output and convert to pyhsical unit.
+ *
+ * See @ref scd4x_read_measurement_raw() for more details.
+ *
+ * @param[out] co2 CO₂ concentration in ppm
+ * @param[out] temperature_m_deg_c Temperature in milli degrees celsius (°C *
+ * 1000)
+ * @param[out] humidity_m_percent_rh Relative humidity in milli percent RH
+ * (%RH * 1000)
+ * @return 0 on success, an error code otherwise
+ */
+int16_t scd4x_read_measurement(uint16_t* co2, int32_t* temperature_m_deg_c,
+                               int32_t* humidity_m_percent_rh);
+
 /**
  * @brief Stop periodic measurement to change the sensor configuration or to
  * save power.