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bmx280: separate funcs for readings
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instead of one giant read func, use magnitude-specific ones
ref. datasheet, adc read failure should have a different constant,
and does not warrant re-init
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@mcspr
mcspr committed Mar 17, 2024
1 parent 37d2837 commit e9ab0a8
Showing 1 changed file with 136 additions and 67 deletions.
203 changes: 136 additions & 67 deletions code/espurna/sensors/BMX280Sensor.h
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Original file line number Diff line number Diff line change
Expand Up @@ -48,29 +48,31 @@
#define BMX280_REGISTER_TEMPDATA 0xFA
#define BMX280_REGISTER_HUMIDDATA 0xFD

#define BMX280_ADC_SKIPPED 0x8000

class BMX280Sensor : public I2CSensor<> {

public:
static constexpr Magnitude Bmp280Magnitudes[] {
#if BMX280_TEMPERATURE
MAGNITUDE_TEMPERATURE,
{MAGNITUDE_TEMPERATURE},
#endif
#if BMX280_PRESSURE
MAGNITUDE_PRESSURE,
{MAGNITUDE_PRESSURE},
#endif
};

static_assert(std::size(Bmp280Magnitudes) > 0, "");

static constexpr Magnitude Bme280Magnitudes[] {
#if BMX280_TEMPERATURE
MAGNITUDE_TEMPERATURE,
{MAGNITUDE_TEMPERATURE},
#endif
#if BMX280_HUMIDITY
MAGNITUDE_HUMIDITY,
{MAGNITUDE_HUMIDITY},
#endif
#if BMX280_PRESSURE
MAGNITUDE_PRESSURE,
{MAGNITUDE_PRESSURE},
#endif
};

Expand Down Expand Up @@ -98,6 +100,10 @@ class BMX280Sensor : public I2CSensor<> {
return String(buffer);
}

String description(unsigned char) const override {
return description();
}

// Type for slot # index
unsigned char type(unsigned char index) const override {
if (index < _count) {
Expand Down Expand Up @@ -146,32 +152,33 @@ class BMX280Sensor : public I2CSensor<> {

// Pre-read hook (usually to populate registers with up-to-date data)
void pre() override {
if (_run_init) {
i2cClearBus();
_init(lockedAddress());
}

if (_chip == 0) {
return;
}

_error = SENSOR_ERROR_OK;

const auto address = lockedAddress();
if (_force_init) {
_error = _forceInit(address);
_force_init = false;
}

if (_error != SENSOR_ERROR_OK) {
return;
}

#if BMX280_MODE == 1
_forceRead(address);
#endif

if (!_wait(address)) {
_error = SENSOR_ERROR_NOT_READY;
_force_init = true;
return;
}

_error = _read(address);
if (_error != SENSOR_ERROR_OK) {
_run_init = true;
}

_read(address);
}

// Current value for slot # index
Expand All @@ -181,10 +188,7 @@ class BMX280Sensor : public I2CSensor<> {
case MAGNITUDE_TEMPERATURE:
return _temperature;
case MAGNITUDE_HUMIDITY:
if (_chip == BMX280_CHIP_BME280) {
return _humidity;
}
break;
return _humidity;
case MAGNITUDE_PRESSURE:
return _pressure;
}
Expand All @@ -195,10 +199,19 @@ class BMX280Sensor : public I2CSensor<> {

// Initialization method, must be idempotent
void begin() override {
if (!_dirty) return;
if (!_find()) return;
_init(lockedAddress());
_dirty = !_ready;
if (!_dirty) {
return;
}

if (!_find()) {
return;
}

_error = _init(lockedAddress());
if (_error == SENSOR_ERROR_OK) {
_ready = true;
_dirty = false;
}
}

void suspend() override {
Expand All @@ -209,7 +222,7 @@ class BMX280Sensor : public I2CSensor<> {
}

void resume() override {
_run_init = true;
_force_init = true;
}

protected:
Expand Down Expand Up @@ -246,15 +259,14 @@ class BMX280Sensor : public I2CSensor<> {
return _chip != 0;
}

void _init(uint8_t address) {
int _init(uint8_t address) {
if (_chip == 0) {
return;
return SENSOR_ERROR_UNKNOWN_ID;
}

i2c_write_uint8(address, BMX280_REGISTER_SOFTRESET, 0xB6);
if (!_wait(address)) {
_error = SENSOR_ERROR_NOT_READY;
return;
return SENSOR_ERROR_NOT_READY;
}

_readCoefficients(address);
Expand All @@ -276,9 +288,12 @@ class BMX280Sensor : public I2CSensor<> {

_measurement_delay = _measurementTime();

_run_init = false;
_ready = true;
return SENSOR_ERROR_OK;
}

int _forceInit(unsigned char address) {
i2cClearBus();
return _init(address);
}

static bool _measurementsReady(uint8_t status) {
Expand Down Expand Up @@ -361,11 +376,13 @@ class BMX280Sensor : public I2CSensor<> {
espurna::time::blockingDelay(_measurement_delay);
}

unsigned char _read(unsigned char address) {

int _readTemperature(unsigned char address) {
#if BMX280_TEMPERATURE
int32_t adc_T = i2c_read_uint16(address, BMX280_REGISTER_TEMPDATA);
if (0xFFFF == adc_T) return SENSOR_ERROR_OUT_OF_RANGE;
if (BMX280_ADC_SKIPPED == adc_T) {
return SENSOR_ERROR_NOT_READY;
}

adc_T <<= 8;
adc_T |= i2c_read_uint8(address, BMX280_REGISTER_TEMPDATA+2);
adc_T >>= 4;
Expand All @@ -379,33 +396,42 @@ class BMX280Sensor : public I2CSensor<> {
((adc_T>>4) - ((int32_t)_bmx280_calib.dig_T1))) >> 12) *
((int32_t)_bmx280_calib.dig_T3)) >> 14;

int32_t t_fine = var1t + var2t;
_t_fine = var1t + var2t;

double T = (t_fine * 5 + 128) >> 8;
double T = (_t_fine * 5 + 128) >> 8;
_temperature = T / 100;

return SENSOR_ERROR_OK;
#else
int32_t t_fine = 102374; // ~20ºC
return SENSOR_ERROR_SUPPORT;
#endif
}

// -----------------------------------------------------------------

int _readPressure(unsigned char address) {
#if BMX280_PRESSURE
int64_t var1, var2, p;

int32_t adc_P = i2c_read_uint16(address, BMX280_REGISTER_PRESSUREDATA);
if (0xFFFF == adc_P) return SENSOR_ERROR_OUT_OF_RANGE;
if (BMX280_ADC_SKIPPED == adc_P) {
return SENSOR_ERROR_NOT_READY;
}

adc_P <<= 8;
adc_P |= i2c_read_uint8(address, BMX280_REGISTER_PRESSUREDATA+2);
adc_P >>= 4;

var1 = ((int64_t)t_fine) - 128000;
var1 = ((int64_t)_t_fine) - 128000;
var2 = var1 * var1 * (int64_t)_bmx280_calib.dig_P6;
var2 = var2 + ((var1*(int64_t)_bmx280_calib.dig_P5)<<17);
var2 = var2 + (((int64_t)_bmx280_calib.dig_P4)<<35);
var1 = ((var1 * var1 * (int64_t)_bmx280_calib.dig_P3)>>8) +
((var1 * (int64_t)_bmx280_calib.dig_P2)<<12);
var1 = (((((int64_t)1)<<47)+var1))*((int64_t)_bmx280_calib.dig_P1)>>33;
if (var1 == 0) return SENSOR_ERROR_OUT_OF_RANGE; // avoid exception caused by division by zero

// avoid exception caused by division by zero
if (var1 == 0) {
return SENSOR_ERROR_OUT_OF_RANGE;
}

p = 1048576 - adc_P;
p = (((p<<31) - var2)*3125) / var1;
Expand All @@ -414,37 +440,78 @@ class BMX280Sensor : public I2CSensor<> {

p = ((p + var1 + var2) >> 8) + (((int64_t)_bmx280_calib.dig_P7)<<4);
_pressure = ((double) p / 256) / 100;
#endif

// -----------------------------------------------------------------
return SENSOR_ERROR_OK;
#else
return SENSOR_ERROR_SUPPORT;
#endif
}

int _readHumidity(unsigned char address) {
#if BMX280_HUMIDITY
if (_chip == BMX280_CHIP_BME280) {
int32_t adc_H = i2c_read_uint16(address, BMX280_REGISTER_HUMIDDATA);
if (0xFFFF == adc_H) return SENSOR_ERROR_OUT_OF_RANGE;
if (_chip != BMX280_CHIP_BME280) {
return SENSOR_ERROR_SUPPORT;
}

int32_t v_x1_u32r;
int32_t adc_H = i2c_read_uint16(address, BMX280_REGISTER_HUMIDDATA);
if (BMX280_ADC_SKIPPED == adc_H) {
return SENSOR_ERROR_NOT_READY;
}

int32_t v_x1_u32r;

v_x1_u32r = (t_fine - ((int32_t)76800));
v_x1_u32r = (_t_fine - ((int32_t)76800));

v_x1_u32r = (((((adc_H << 14) - (((int32_t)_bmx280_calib.dig_H4) << 20) -
(((int32_t)_bmx280_calib.dig_H5) * v_x1_u32r)) + ((int32_t)16384)) >> 15) *
v_x1_u32r = (((((adc_H << 14) - (((int32_t)_bmx280_calib.dig_H4) << 20) -
(((int32_t)_bmx280_calib.dig_H5) * v_x1_u32r)) + ((int32_t)16384)) >> 15) *
(((((((v_x1_u32r * ((int32_t)_bmx280_calib.dig_H6)) >> 10) *
(((v_x1_u32r * ((int32_t)_bmx280_calib.dig_H3)) >> 11) + ((int32_t)32768))) >> 10) +
((int32_t)2097152)) * ((int32_t)_bmx280_calib.dig_H2) + 8192) >> 14));
(((v_x1_u32r * ((int32_t)_bmx280_calib.dig_H3)) >> 11) + ((int32_t)32768))) >> 10) +
((int32_t)2097152)) * ((int32_t)_bmx280_calib.dig_H2) + 8192) >> 14));

v_x1_u32r = (v_x1_u32r - (((((v_x1_u32r >> 15) * (v_x1_u32r >> 15)) >> 7) *
((int32_t)_bmx280_calib.dig_H1)) >> 4));
v_x1_u32r = (v_x1_u32r - (((((v_x1_u32r >> 15) * (v_x1_u32r >> 15)) >> 7) *
((int32_t)_bmx280_calib.dig_H1)) >> 4));

v_x1_u32r = (v_x1_u32r < 0) ? 0 : v_x1_u32r;
v_x1_u32r = (v_x1_u32r > 419430400) ? 419430400 : v_x1_u32r;
double h = (v_x1_u32r >> 12);
_humidity = h / 1024.0;
}
#endif
v_x1_u32r = (v_x1_u32r < 0) ? 0 : v_x1_u32r;
v_x1_u32r = (v_x1_u32r > 419430400) ? 419430400 : v_x1_u32r;

double h = (v_x1_u32r >> 12);
_humidity = h / 1024.0;

return SENSOR_ERROR_OK;
#else
return SENSOR_ERROR_SUPPORT;
#endif
}

// in case t_fine is not updated by temperature readings
void _preRead() {
static constexpr int32_t DefaultTFine{ 102374 }; // ~20ºC
_t_fine = DefaultTFine;
}

// ready every available register from the given address
void _read(unsigned char address) {
_preRead();

for (size_t index = 0; index < _count; ++index) {
switch (_magnitudes[index].type) {
case MAGNITUDE_TEMPERATURE:
_error = _readTemperature(address);
break;

case MAGNITUDE_HUMIDITY:
_error = _readHumidity(address);
break;

case MAGNITUDE_PRESSURE:
_error = _readPressure(address);
break;
}

if (_error != SENSOR_ERROR_OK) {
break;
}
}
}

// ---------------------------------------------------------------------
Expand All @@ -454,15 +521,17 @@ class BMX280Sensor : public I2CSensor<> {

espurna::duration::Milliseconds _measurement_delay;

bool _run_init = false;
double _temperature = 0;
double _humidity = 0;
double _pressure = 0;
double _temperature{};
double _humidity{};
double _pressure{};

uint8_t _chip { 0 };
bool _force_init { false };

uint8_t _chip = 0;
const Magnitude* _magnitudes { nullptr };
size_t _count { 0 };

const Magnitude* _magnitudes = nullptr;
size_t _count = 0;
int32_t _t_fine;

struct bmx280_calib_t {
uint16_t dig_T1;
Expand Down

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