From 8be1b4bdb4a678e9eced4022cbc792e403111edd Mon Sep 17 00:00:00 2001
From: Michael Keller <github@ike.ch>
Date: Sun, 17 Jan 2021 00:16:06 +1300
Subject: [PATCH] Fixed incorrect parameter value for barometer sample count.

---
 src/main/cli/settings.c      |  2 +-
 src/main/sensors/barometer.c | 18 ++++++++----------
 2 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/src/main/cli/settings.c b/src/main/cli/settings.c
index 07aa97b34e..41f3e78e89 100644
--- a/src/main/cli/settings.c
+++ b/src/main/cli/settings.c
@@ -726,7 +726,7 @@ const clivalue_t valueTable[] = {
     { "baro_i2c_device",            VAR_UINT8  | HARDWARE_VALUE, .config.minmaxUnsigned = { 0, 5 }, PG_BAROMETER_CONFIG, offsetof(barometerConfig_t, baro_i2c_device) },
     { "baro_i2c_address",           VAR_UINT8  | HARDWARE_VALUE, .config.minmaxUnsigned = { 0, I2C_ADDR7_MAX }, PG_BAROMETER_CONFIG, offsetof(barometerConfig_t, baro_i2c_address) },
     { "baro_hardware",              VAR_UINT8  | MASTER_VALUE | MODE_LOOKUP, .config.lookup = { TABLE_BARO_HARDWARE }, PG_BAROMETER_CONFIG, offsetof(barometerConfig_t, baro_hardware) },
-    { "baro_tab_size",              VAR_UINT8  | MASTER_VALUE, .config.minmaxUnsigned = { 2, BARO_SAMPLE_COUNT_MAX }, PG_BAROMETER_CONFIG, offsetof(barometerConfig_t, baro_sample_count) },
+    { "baro_tab_size",              VAR_UINT8  | MASTER_VALUE, .config.minmaxUnsigned = { 1, BARO_SAMPLE_COUNT_MAX }, PG_BAROMETER_CONFIG, offsetof(barometerConfig_t, baro_sample_count) },
     { "baro_noise_lpf",             VAR_UINT16  | MASTER_VALUE, .config.minmaxUnsigned = { 0, 1000 }, PG_BAROMETER_CONFIG, offsetof(barometerConfig_t, baro_noise_lpf) },
     { "baro_cf_vel",                VAR_UINT16  | MASTER_VALUE, .config.minmaxUnsigned = { 0, 1000 }, PG_BAROMETER_CONFIG, offsetof(barometerConfig_t, baro_cf_vel) },
 #endif
diff --git a/src/main/sensors/barometer.c b/src/main/sensors/barometer.c
index d774ea27c4..f31a30c93c 100644
--- a/src/main/sensors/barometer.c
+++ b/src/main/sensors/barometer.c
@@ -338,24 +338,22 @@ static int32_t applyBarometerMedianFilter(int32_t newPressureReading)
         return newPressureReading;
 }
 
-#define PRESSURE_SAMPLE_COUNT (barometerConfig()->baro_sample_count - 1)
-
-static uint32_t recalculateBarometerTotal(uint8_t baroSampleCount, uint32_t pressureTotal, int32_t newPressureReading)
+static uint32_t recalculateBarometerTotal(uint32_t pressureTotal, int32_t newPressureReading)
 {
-    static int32_t barometerSamples[BARO_SAMPLE_COUNT_MAX];
+    static int32_t barometerSamples[BARO_SAMPLE_COUNT_MAX + 1];
     static int currentSampleIndex = 0;
     int nextSampleIndex;
 
     // store current pressure in barometerSamples
-    nextSampleIndex = (currentSampleIndex + 1);
-    if (nextSampleIndex == baroSampleCount) {
+    if (currentSampleIndex >= barometerConfig()->baro_sample_count) {
         nextSampleIndex = 0;
         baroReady = true;
+    } else {
+	    nextSampleIndex = (currentSampleIndex + 1);
     }
     barometerSamples[currentSampleIndex] = applyBarometerMedianFilter(newPressureReading);
 
     // recalculate pressure total
-    // Note, the pressure total is made up of baroSampleCount - 1 samples - See PRESSURE_SAMPLE_COUNT
     pressureTotal += barometerSamples[currentSampleIndex];
     pressureTotal -= barometerSamples[nextSampleIndex];
 
@@ -427,7 +425,7 @@ uint32_t baroUpdate(void)
             baro.dev.calculate(&baroPressure, &baroTemperature);
             baro.baroPressure = baroPressure;
             baro.baroTemperature = baroTemperature;
-            baroPressureSum = recalculateBarometerTotal(barometerConfig()->baro_sample_count, baroPressureSum, baroPressure);
+            baroPressureSum = recalculateBarometerTotal(baroPressureSum, baroPressure);
             if (baro.dev.combined_read) {
                 state = BAROMETER_NEEDS_PRESSURE_START;
             } else {
@@ -458,7 +456,7 @@ int32_t baroCalculateAltitude(void)
 
     // calculates height from ground via baro readings
     if (baroIsCalibrationComplete()) {
-        BaroAlt_tmp = lrintf(pressureToAltitude((float)(baroPressureSum / PRESSURE_SAMPLE_COUNT)));
+        BaroAlt_tmp = lrintf(pressureToAltitude((float)(baroPressureSum / barometerConfig()->baro_sample_count)));
         BaroAlt_tmp -= baroGroundAltitude;
         baro.BaroAlt = lrintf((float)baro.BaroAlt * CONVERT_PARAMETER_TO_FLOAT(barometerConfig()->baro_noise_lpf) + (float)BaroAlt_tmp * (1.0f - CONVERT_PARAMETER_TO_FLOAT(barometerConfig()->baro_noise_lpf))); // additional LPF to reduce baro noise
     }
@@ -473,7 +471,7 @@ void performBaroCalibrationCycle(void)
     static int32_t savedGroundPressure = 0;
 
     baroGroundPressure -= baroGroundPressure / 8;
-    baroGroundPressure += baroPressureSum / PRESSURE_SAMPLE_COUNT;
+    baroGroundPressure += baroPressureSum / barometerConfig()->baro_sample_count;
     baroGroundAltitude = (1.0f - pow_approx((baroGroundPressure / 8) / 101325.0f, 0.190259f)) * 4433000.0f;
 
     if (baroGroundPressure == savedGroundPressure) {