From e47498b8bd1c232f45f28f2af3cbf59b0b66b46a Mon Sep 17 00:00:00 2001
From: Anatole SCHRAMM <schramma@ldlcxl0013.ldl.st.com>
Date: Thu, 11 Jan 2024 13:41:43 +0100
Subject: [PATCH] Improved pressure computation function by reading the
 pressure and temperature registers in one shot

---
 .../app/app_drivers/i2c/BMP280.c              | 56 +++++++++++--------
 1 file changed, 33 insertions(+), 23 deletions(-)

diff --git a/src/W800_SDK_v1.00.10/app/app_drivers/i2c/BMP280.c b/src/W800_SDK_v1.00.10/app/app_drivers/i2c/BMP280.c
index 2fb83cd..e2b9c38 100644
--- a/src/W800_SDK_v1.00.10/app/app_drivers/i2c/BMP280.c
+++ b/src/W800_SDK_v1.00.10/app/app_drivers/i2c/BMP280.c
@@ -117,6 +117,28 @@ static bool _BMP280_read_calibration_data(void)
     return true;
 }
 
+static float _BMP280_compute_temperature(uint8_t *data)
+{
+    int32_t var1, var2;
+    int32_t adc_T = data[0] << 16 | data[1] << 8 | data[2];
+    adc_T >>= 4;
+
+    var1 = ((((adc_T >> 3) - ((int32_t)_calibration_data.dig_T1 << 1))) *
+            ((int32_t)_calibration_data.dig_T2)) >>
+           11;
+
+    var2 = (((((adc_T >> 4) - ((int32_t)_calibration_data.dig_T1)) *
+              ((adc_T >> 4) - ((int32_t)_calibration_data.dig_T1))) >>
+             12) *
+            ((int32_t)_calibration_data.dig_T3)) >>
+           14;
+
+    t_fine = var1 + var2;
+
+    float T = (t_fine * 5 + 128) >> 8;
+    return T / 100.0;
+}
+
 bool BMP280_init(void)
 {
     uint8_t data;
@@ -162,39 +184,27 @@ bool BMP280_is_measuring(void)
 
 float BMP280_get_temperature(void)
 {
-    int32_t var1, var2;
     uint8_t data[3];
 
     if(!i2c_read(BMP280_I2C_ADDR, BMP280_TEMP_MSB, data, sizeof data)) return 0.0f;
 
-    int32_t adc_T = data[0] << 16 | data[1] << 8 | data[2];
-    adc_T >>= 4;
-
-    var1 = ((((adc_T >> 3) - ((int32_t)_calibration_data.dig_T1 << 1))) *
-            ((int32_t)_calibration_data.dig_T2)) >>
-           11;
-
-    var2 = (((((adc_T >> 4) - ((int32_t)_calibration_data.dig_T1)) *
-              ((adc_T >> 4) - ((int32_t)_calibration_data.dig_T1))) >>
-             12) *
-            ((int32_t)_calibration_data.dig_T3)) >>
-           14;
-
-    t_fine = var1 + var2;
-
-    float T = (t_fine * 5 + 128) >> 8;
-    return T / 100;
+    return _BMP280_compute_temperature(data);
 }
 
 float BMP280_get_pressure(float * const temperature)
 {
     int64_t var1, var2, p;
-    uint8_t data[3];
-
-    float temp = BMP280_get_temperature();
-    if(temperature) *temperature = temp;
+    uint8_t data[6];
     
-    if(!i2c_read(BMP280_I2C_ADDR, BMP280_PRESS_MSB, data, sizeof data)) return 0.0f;
+    /* When reading the pressure, we also need to get the associated temperature, so let's read everything at once */
+    if(!i2c_read(BMP280_I2C_ADDR, BMP280_PRESS_MSB, data, sizeof data))
+    {
+        if(temperature) *temperature = 0.0f;
+        return 0.0f;
+    }
+
+    float temp = _BMP280_compute_temperature(&data[3]);
+    if(temperature) *temperature = temp;
 
     int32_t adc_P = data[0] << 16 | data[1] << 8 | data[2];
     adc_P >>= 4;