From 7505f04558d353bb89556e29e63f98864839615c Mon Sep 17 00:00:00 2001
From: dario <dario.vandenboom@arcor.de>
Date: Sun, 28 Apr 2024 10:56:42 +0200
Subject: [PATCH] Changes to make use of previous temperature measurements

---
 include/sta/drivers/MS56xx.hpp |  9 ++++--
 src/MS56xx.cpp                 | 54 ++++++++++++----------------------
 2 files changed, 25 insertions(+), 38 deletions(-)

diff --git a/include/sta/drivers/MS56xx.hpp b/include/sta/drivers/MS56xx.hpp
index 651ff73..e90dffe 100644
--- a/include/sta/drivers/MS56xx.hpp
+++ b/include/sta/drivers/MS56xx.hpp
@@ -119,9 +119,10 @@ namespace sta
          * @brief Reads the current pressure value from the sensor. Obtains the temperature value from the interal sensor.
          * 
          * @param unit Specifies the unit for the pressure measurement. Default is hPa.
+         * @param cachedTemp Specifies if a cached temperature value should be used.
          * @return int32_t The measured value in the specified unit.
          */
-        float getPressure(Unit unit = Unit::hPa);
+        float getPressure(Unit unit = Unit::hPa, bool cachedTemp = false);
 
         /**
          * @brief Reads the current temperature value from the sensor.
@@ -129,7 +130,7 @@ namespace sta
          * @return int32_t The measured temperature.
          * @note There are better sensors for temperature measurements than the MS56xx.
          */
-        int32_t getTemperature();
+        float getTemperature();
 
         /**
          * @brief Provide a reference pressure value at a reference altitude in order to estimate the sealevel pressure.
@@ -216,6 +217,8 @@ namespace sta
         OsrLevel osr_;
         Intf intf_;
 
+        float dT_;
+
         // Pressure at sealevel. Use the standard atmosphere per default.
         float sealevel_ = 1013.25;
 
@@ -227,4 +230,4 @@ namespace sta
     };
 }
 
-#endif // ifndef STA_SENSORS_MS5607_HPP
\ No newline at end of file
+#endif // ifndef STA_SENSORS_MS5607_HPP
diff --git a/src/MS56xx.cpp b/src/MS56xx.cpp
index 0222708..0868e26 100644
--- a/src/MS56xx.cpp
+++ b/src/MS56xx.cpp
@@ -53,7 +53,7 @@ namespace sta
         delay_(MS56xx::RESET_DELAY);
     }
 
-    float MS56xx::getPressure(Unit unit /* = Unit::hPa */)
+    float MS56xx::getPressure(Unit unit /* = Unit::hPa */, bool cachedTemp /* = false */)
     {
         // Request the ADC to read pressure values.
         busCommand(MS56xx::Operations::D1_CONVERSION + 2*this->osr_);
@@ -66,39 +66,23 @@ namespace sta
 
         uint32_t D1 = 0x00 | buffer[0] << 16 | buffer[1] << 8 | buffer[2];
 
-        // Request the ADC to read temperature values.
-        busCommand(MS56xx::Operations::D2_CONVERSION + 2*this->osr_);
-
-        // 8.22 ms conversion according to the datasheet.
-        delay_(osrDelay());
-
-        busRead(MS56xx::Operations::ADC_RESULT, buffer, 3);
-
-        uint32_t D2 = buffer[0] << 16 | buffer[1] << 8 | buffer[2];
-
-        float dT = D2 - C_[5];
-        float offset =  C_[2] + dT * C_[4];
-        float sens = C_[1] + dT * C_[3];
-
-        /*
-        if (temperature < 2000)
+        if (!cachedTemp)
         {
-            float T2 = dT * dT * 4.6566128731E-10;
-            float t = (temperature - 2000) * (temperature - 2000);
-            float offset2 = 2.5 * t;
-            float sens2 = 1.25 * t;
-            //  COMMENT OUT < -1500 CORRECTION IF NOT NEEDED
-            if (temperature < -1500)
-            {
-                t = (temperature + 1500) * (temperature + 1500);
-                offset2 += 7 * t;
-                sens2 += 5.5 * t;
-            }
-            temperature -= T2;
-            offset -= offset2;
-            sens -= sens2;
+        	// Request the ADC to read temperature values.
+			busCommand(MS56xx::Operations::D2_CONVERSION + 2*this->osr_);
+
+			// 8.22 ms conversion according to the datasheet.
+			delay_(osrDelay());
+
+			busRead(MS56xx::Operations::ADC_RESULT, buffer, 3);
+
+			uint32_t D2 = buffer[0] << 16 | buffer[1] << 8 | buffer[2];
+
+			dT_ = D2 - C_[5];
         }
-        */
+
+        float offset =  C_[2] + dT_ * C_[4];
+        float sens = C_[1] + dT_ * C_[3];
 
         // The pressure in Pa.
         float pressure = (D1 * sens * 4.76837158205E-7 - offset) * 3.051757813E-5;
@@ -107,7 +91,7 @@ namespace sta
         return pressure * 0.01;
     }
 
-    int32_t MS56xx::getTemperature()
+    float MS56xx::getTemperature()
     {
     	// Request the ADC to read temperature values.
 		busCommand(MS56xx::Operations::D2_CONVERSION + 2*this->osr_);
@@ -120,8 +104,8 @@ namespace sta
 
 		uint32_t D2 = buffer[0] << 16 | buffer[1] << 8 | buffer[2];
 
-    	float dT = D2 - C_[5];
-    	float temperature = 2000 + dT * C_[6];
+    	dT_ = D2 - C_[5];
+    	float temperature = 2000 + dT_ * C_[6];
 
     	return temperature * 0.01;
     }