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enable IIR filtering for BME280 #1048

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enable IIR filtering for BME280 #1048

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3 changes: 2 additions & 1 deletion airrohr-firmware/airrohr-firmware.ino
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Original file line number Diff line number Diff line change
Expand Up @@ -5408,7 +5408,8 @@ static bool initBMX280(char addr)
BMX280::MODE_FORCED,
BMX280::SAMPLING_X1,
BMX280::SAMPLING_X1,
BMX280::SAMPLING_X1);
BMX280::SAMPLING_X1,
BMX280::IIR_16);
return true;
}
else
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2 changes: 2 additions & 0 deletions airrohr-firmware/bmx280_i2c.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -129,6 +129,7 @@ void BMX280::setSampling(sensor_mode mode,
sensor_sampling tempSampling,
sensor_sampling pressSampling,
sensor_sampling humSampling,
iir_filter iirFilter,
standby_duration duration) {

_measReg.mode = mode;
Expand All @@ -140,6 +141,7 @@ void BMX280::setSampling(sensor_mode mode,

config _configReg;
_configReg.t_sb = duration;
_configReg.filter = iirFilter;

// making sure sensor is in sleep mode before setting configuration
// as it otherwise may be ignored
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30 changes: 24 additions & 6 deletions airrohr-firmware/bmx280_i2c.h
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Expand Up @@ -50,6 +50,19 @@ class BMX280 {
SAMPLING_X16 = 0b101
};

/**************************************************************************/
/*!
@brief IIR filter
*/
/**************************************************************************/
enum iir_filter {
IIR_NONE = 0b000,
IIR_2 = 0b001,
IIR_4 = 0b010,
IIR_8 = 0b011,
IIR_16 = 0b100
};

/**************************************************************************/
/*!
@brief power modes
Expand Down Expand Up @@ -82,6 +95,7 @@ class BMX280 {
sensor_sampling tempSampling = SAMPLING_X16,
sensor_sampling pressSampling = SAMPLING_X16,
sensor_sampling humSampling = SAMPLING_X16,
iir_filter iirFilter = IIR_NONE,
standby_duration duration = STANDBY_MS_0_5);

void takeForcedMeasurement();
Expand Down Expand Up @@ -146,14 +160,18 @@ class BMX280 {
// 111 = 20 ms
uint8_t t_sb : 3; ///< inactive duration (standby time) in normal mode

// unused - don't set
uint8_t none : 1; ///< unused - don't set
// Controls the time constant of the IIR filter
// 000 = off
// 001 = 2
// 010 = 4
// 011 = 8
// 100, others = 16
uint8_t filter : 3; ///< Controls the time constant of the IIR filter
uint8_t none : 1; ///< unused - don't set
uint8_t spi3w_en : 1; ///< unused - don't set

uint8_t _unused : 3;


/// @return combined config register
uint8_t get() { return (t_sb << 5); }
uint8_t get() { return (t_sb << 5) | (filter << 2); }
};

/**************************************************************************/
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