diff --git a/include/sta/MS5607.hpp b/include/sta/MS5607.hpp index 32531e5..eaad14b 100644 --- a/include/sta/MS5607.hpp +++ b/include/sta/MS5607.hpp @@ -6,8 +6,10 @@ #include namespace sta { + // Class to represent a MS5607 pressure sensor which is used with SPI class MS5607 { public: + // Different OSR levels for the sensor enum OsrLevel { _256 = 0, _512 = 1, @@ -18,17 +20,25 @@ namespace sta { MS5607(SpiDevice* device, OsrLevel osr=OsrLevel::_1024); + // Getter for pressure int32_t getPressure(); + // Getter for temperature int32_t getTemperature(); - void changeOsrLevel(OsrLevel newOsr) { this->osr_ = newOsr; } + void changeOsrLevel(OsrLevel newOsr) { + // Don't I need to write this to the sensor? + this->osr_ = newOsr; + } private: + // STA internal object for SPi abstraction SpiDevice* device_; OsrLevel osr_; + // 6 Different constants; Includes Offsets, references etc. uint16_t sens, off, tcs, tco, t_ref, tempsens; + // All possible commands to send to the sensor enum Operations { RESET = 0x1E, READ_PROM = 0xA2, @@ -37,17 +47,18 @@ namespace sta { ADC_RESULT = 0x00 }; + // Request pure ADC converted values from the sensor + // Calculations with offset required uint32_t readPressure(); uint32_t readTemp(); + // Calculate pure ADC values to final pressure/temperature values int32_t calculatePressure(uint32_t d1, int32_t dT); int32_t calculateTemperature(uint32_t d2); void reset(); void readPROM(); - // Take first bytes from buffer, swap them and store those in uint16_t - static uint16_t uint_8BufferTouint16_t(uint8_t* buffer); - + // Constants for waiting const char RESET_DELAY = 2800; // in uS const char ADC_DELAY = 8220; // in uS; not sure if thats correct since the datasheet doesn't say anything explicitly }; diff --git a/src/MS5607.cpp b/src/MS5607.cpp index 46db2f9..c50f6ae 100644 --- a/src/MS5607.cpp +++ b/src/MS5607.cpp @@ -5,11 +5,14 @@ namespace sta { this->device_ = device; this->osr_ = level; + // Reset device on start-up this->reset(); + // Read the PROM e.g. constants this->readPROM(); } int32_t MS5607::getPressure() { + // Get pure ADC value from the sensor uint32_t d1 = readPressure(); // Since pressure is temp-dependant, temperature needs to be polled @@ -22,22 +25,29 @@ namespace sta { } uint32_t MS5607::readPressure() { + // Request pressure value conversion this->device_->beginTransmission(); this->device_->transfer(MS5607::Operations::D1_CONVERSION + 2*this->osr_); this->device_->endTransmission(); + // Wait for ADC to finish delayUs(MS5607::ADC_DELAY); - uint8_t d1Arr[3]; + // Request read of ADC value + uint8_t d1Arr[3]; this->device_->beginTransmission(); this->device_->receive(d1Arr, 3); this->device_->endTransmission(); + // Convert into best possible type uint32_t res = 0; res |= d1Arr[0] | (d1Arr[1] << 8) | (d1Arr[2] << 16); return res; } + // Calculations from the Datasheet + // Probably problems with type conversions + // If we used Rust... int32_t MS5607::calculatePressure(uint32_t d1, int32_t dT) { int64_t offset = (this->off << 17) + ((this->tco * dT) >> 6); int64_t sensitivity = (this->sens << 16) + ((this->tcs * dT) >> 7); @@ -46,28 +56,36 @@ namespace sta { } int32_t MS5607::getTemperature() { + // Get pure ADC value from the sensor uint32_t d2 = readTemp(); - calculateTemperature(d2); + return calculateTemperature(d2); } uint32_t MS5607::readTemp() { + // Request ADC conversion of temperature this->device_->beginTransmission(); this->device_->transfer(MS5607::Operations::D2_CONVERSION + 2*this->osr_); this->device_->endTransmission(); + // Wait for ADC to finish delayUs(MS5607::ADC_DELAY); - uint8_t d2Arr[3]; + // Request ADC readout + uint8_t d2Arr[3]; this->device_->beginTransmission(); this->device_->receive(d2Arr, 3); this->device_->endTransmission(); + // Convert into best possible type uint32_t res = 0; res |= d2Arr[0] | d2Arr[1] << 8 | d2Arr[2] << 16; return res; } + // Calculations from the Datasheet + // Probably problems with type conversions + // If we used Rust... int32_t MS5607::calculateTemperature(uint32_t d2) { int32_t dT = d2 - (this->t_ref << 8); int32_t temp = 2000 + ((dT * this->tempsens) >> 23); @@ -78,6 +96,7 @@ namespace sta { return temp; } + // Reset sequence as described in datasheet void MS5607::reset() { this->device_->beginTransmission(); this->device_->transfer(MS5607::Operations::RESET); @@ -85,6 +104,10 @@ namespace sta { delayUs(MS5607::RESET_DELAY); } + // Read all constants from the PROM + // May be moved to be called in reset() function in future + // Request value x -> Read value x; Then request value y etc. + // Could be optimized; Not as important since only needed once at start-up void MS5607::readPROM() { this->device_->beginTransmission(); @@ -121,7 +144,10 @@ namespace sta { this->device_->endTransmission(); } - uint16_t MS5607::uint_8BufferTouint16_t(uint8_t* buffer) { + // Helper function: + // Take first bytes from buffer, swap them and store those in uint16_t + // Swap may not be necessary + uint16_t uint_8BufferTouint16_t(uint8_t* buffer) { return (buffer[0] << 8) | buffer[1]; } } \ No newline at end of file