Prototyping/f4projects/f4discovery_tests/inc/bmp180.h

/*
 * bmp_180.h
 *
 *  Created on: 2 îêò. 2016 ã.
 *      Author: l-pro
 */

#ifndef BMP180_H_
#define BMP180_H_

#include "stm32f4xx_hal.h"
#include <cstdint>
#include <cmath>

extern I2C_HandleTypeDef hi2c3;

namespace Bmp180Registers {
	static constexpr uint8_t Control = 0xF4;
	static constexpr uint8_t TempData = 0xF6;
	static constexpr uint8_t PressureData = 0xF6;
	static constexpr uint8_t SoftReset = 0xE0;
	static constexpr uint8_t ChipID = 0xD0;

	static constexpr uint8_t Ac1 = 0xAA;
	static constexpr uint8_t Ac2 = 0xAC;
	static constexpr uint8_t Ac3 = 0xAE;
	static constexpr uint8_t Ac4 = 0xB0;
	static constexpr uint8_t Ac5 = 0xB2;
	static constexpr uint8_t Ac6 = 0xB4;
	static constexpr uint8_t B1 = 0xB6;
	static constexpr uint8_t B2 = 0xB8;
	static constexpr uint8_t Mb = 0xBA;
	static constexpr uint8_t Mc = 0xBC;
	static constexpr uint8_t Md = 0xBE;
}

namespace Bmp180Commands {
	static constexpr uint8_t ReadTempCmd = 0x2E;
	static constexpr uint8_t ReadPressureCmd = 0x34;
}

enum class Bmp180Oversampling : uint8_t {
	UltraLowPower = 0,
	Standard = 1,
	Highres = 2,
	UltraHighRes = 3
};

struct Bmp180CalibrationData {
	int16_t ac1;
	int16_t ac2;
	int16_t ac3;
	uint16_t ac4;
	uint16_t ac5;
	uint16_t ac6;
	int16_t b1;
	int16_t b2;
	int16_t mb;
	int16_t mc;
	int16_t md;
};

class Bmp180 {
public:
	static constexpr uint8_t I2CAddress = 0x77 << 1;
	static constexpr uint8_t ChipID = 0x55;

	uint8_t read8(uint8_t address);
	void read16(uint8_t address, uint16_t* data);
	void write8(uint8_t address, uint8_t data);
	static void delayUs(uint32_t us);

	static int32_t calcB5(uint16_t rawTemperature,const Bmp180CalibrationData& data){
		int32_t UT = (int32_t)rawTemperature;
		int32_t x1 = ((UT - (int32_t)data.ac6) * (int32_t)data.ac5) / (int32_t)(1 << 15);
		int32_t x2 = ((int32_t)data.mc * (int32_t)(1 << 11)) / (x1+(int32_t)data.md);
		return x1 + x2;
	}

	static int32_t rawToTrueTemperature(uint16_t rawTemperature, const Bmp180CalibrationData& data){
		return (calcB5(rawTemperature, data) + 8) / (int32_t)(1 << 4);
	}

	static int32_t rawToTruePressure(uint16_t rawTemperature, uint32_t rawPressure, Bmp180Oversampling oversampling, const Bmp180CalibrationData& data){
		auto b5 = calcB5(rawTemperature, data);

		int32_t b6 = b5 - 4000;
		int32_t x1 = ((int32_t)data.b2 * ((b6 * b6) / (1 << 12))) / (1 << 11);
		int32_t x2 = ((int32_t)data.ac2 * b6) / (1 << 11);
		int32_t x3 = x1 + x2;
		int32_t b3 = ((((int32_t)data.ac1*4 + x3) << (uint8_t)oversampling) + 2) / 4;
		x1 = ((int32_t)data.ac3 * b6) / (1 << 13);
		x2 = (data.b1 *((b6*b6)/ (1 << 12))) / (1 << 16);
		x3 = ((x1 + x2) + 2) / (1 << 2);
		uint32_t b4 = ((uint32_t)data.ac4 * (uint32_t)(x3 + 32768)) / (1 << 15);
		uint32_t b7 = (rawPressure - b3)*(uint32_t)(50000 >> (uint8_t)oversampling);

		int32_t p = 0;
		if(b7 < 0x80000000){
			p = (b7 * 2) / b4;
		}else{
			p = (b7 / b4) * 2;
		}

		x1 = (p / (1 << 8)) * (p / (1 << 8));
		x1 = (x1 * 3038) / (1 << 16);
		x2 = ((int32_t)-7357 * p) / (1 << 16);
		return p + (x1 + x2 + (int32_t)3791) / (1 << 4);
	}

	static float pressureToAltitude(int32_t pressure, float seaLevelPressure){
		return 44330.0f * (1.0f - std::pow((float)pressure / seaLevelPressure, 1.0f / 5.255f));
	}

	bool init();
	uint16_t readRawTemperature();
	uint32_t readRawPressure(Bmp180Oversampling oversampling);

	void readCalibrationData(Bmp180CalibrationData& data);
};

void Bmp180::delayUs(uint32_t us){
	HAL_Delay((us + 999) / 1000);
}

bool Bmp180::init(){
	if (read8(Bmp180Registers::ChipID) != ChipID) {
		return false;
	}

	return true;
}

uint16_t Bmp180::readRawTemperature(){
	write8(Bmp180Registers::Control, Bmp180Commands::ReadTempCmd);
	delayUs(4500);
	uint16_t result;
	read16(Bmp180Registers::TempData, &result);
	return result;
}

uint32_t Bmp180::readRawPressure(Bmp180Oversampling oversampling){
	write8(Bmp180Registers::Control, Bmp180Commands::ReadPressureCmd | ((uint8_t)oversampling << 6));

	if(oversampling == Bmp180Oversampling::UltraLowPower){
		delayUs(4500);
	}else if(oversampling == Bmp180Oversampling::Standard){
		delayUs(8000);
	}else if(oversampling == Bmp180Oversampling::Highres){
		delayUs(14000);
	}else{
		delayUs(26000);
	}

	uint32_t pressure = 0;
	read16(Bmp180Registers::PressureData, reinterpret_cast<uint16_t*>(&pressure));
	pressure = (pressure << 8) | read8(Bmp180Registers::PressureData + 2);
	pressure >>= (8 - (uint8_t)(oversampling));
	return pressure;
}

void Bmp180::readCalibrationData(Bmp180CalibrationData& data){
	read16(Bmp180Registers::Ac1, reinterpret_cast<uint16_t*>(&data.ac1));
	read16(Bmp180Registers::Ac2, reinterpret_cast<uint16_t*>(&data.ac2));
	read16(Bmp180Registers::Ac3, reinterpret_cast<uint16_t*>(&data.ac3));
	read16(Bmp180Registers::Ac4, &data.ac4);
	read16(Bmp180Registers::Ac5, &data.ac5);
	read16(Bmp180Registers::Ac6, &data.ac6);
	read16(Bmp180Registers::B1, reinterpret_cast<uint16_t*>(&data.b1));
	read16(Bmp180Registers::B2, reinterpret_cast<uint16_t*>(&data.b2));
	read16(Bmp180Registers::Mb, reinterpret_cast<uint16_t*>(&data.mb));
	read16(Bmp180Registers::Mc, reinterpret_cast<uint16_t*>(&data.mc));
	read16(Bmp180Registers::Md, reinterpret_cast<uint16_t*>(&data.md));
}

uint8_t Bmp180::read8(uint8_t address) {
	uint8_t result = 0;
	HAL_I2C_Master_Transmit(&hi2c3, I2CAddress, &address, 1, HAL_MAX_DELAY);
	HAL_I2C_Master_Receive(&hi2c3, I2CAddress, &result, 1, HAL_MAX_DELAY);
	return result;
}

void Bmp180::read16(uint8_t address, uint16_t* data) {
	HAL_I2C_Master_Transmit(&hi2c3, I2CAddress, &address, 1, HAL_MAX_DELAY);
	HAL_I2C_Master_Receive(&hi2c3, I2CAddress, reinterpret_cast<uint8_t*>(data), 2, HAL_MAX_DELAY);

	//swap bytes
	*data = (((*data) & 0xff) << 8) | (((*data) & 0xff00) >> 8);
}

void Bmp180::write8(uint8_t address, uint8_t data){
	uint8_t bytes[] = {address, data};
	HAL_I2C_Master_Transmit(&hi2c3, I2CAddress, &bytes[0], 2, HAL_MAX_DELAY);
}

#endif /* BMP180_H_ */