Rune Harlyk
130 lines
3.7 KiB
C++
130 lines
3.7 KiB
C++
#pragma once
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#include <peripherals/i2c_bus.h>
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#include <cmath>
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class BMP180Driver {
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public:
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static constexpr uint8_t DEFAULT_ADDR = 0x77;
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static constexpr float SEA_LEVEL_HPA = 1013.25f;
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BMP180Driver(uint8_t addr = DEFAULT_ADDR) : _addr(addr) {}
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bool begin() {
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if (!I2CBus::instance().probe(_addr)) return false;
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uint8_t id = readReg8(REG_CHIP_ID);
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if (id != 0x55) return false;
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_ac1 = readReg16(0xAA);
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_ac2 = readReg16(0xAC);
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_ac3 = readReg16(0xAE);
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_ac4 = readReg16U(0xB0);
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_ac5 = readReg16U(0xB2);
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_ac6 = readReg16U(0xB4);
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_b1 = readReg16(0xB6);
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_b2 = readReg16(0xB8);
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_mb = readReg16(0xBA);
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_mc = readReg16(0xBC);
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_md = readReg16(0xBE);
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_initialized = true;
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return true;
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}
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bool update() {
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if (!_initialized) return false;
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writeReg(REG_CONTROL, CMD_TEMP);
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vTaskDelay(pdMS_TO_TICKS(5));
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int32_t ut = readReg16(REG_OUT_MSB);
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writeReg(REG_CONTROL, CMD_PRESSURE + (_oss << 6));
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vTaskDelay(pdMS_TO_TICKS(2 + (3 << _oss)));
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int32_t up = readReg24(REG_OUT_MSB) >> (8 - _oss);
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int32_t x1 = ((ut - _ac6) * _ac5) >> 15;
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int32_t x2 = (_mc << 11) / (x1 + _md);
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int32_t b5 = x1 + x2;
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_temperature = ((b5 + 8) >> 4) / 10.0f;
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int32_t b6 = b5 - 4000;
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x1 = (_b2 * ((b6 * b6) >> 12)) >> 11;
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x2 = (_ac2 * b6) >> 11;
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int32_t x3 = x1 + x2;
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int32_t b3 = (((_ac1 * 4 + x3) << _oss) + 2) >> 2;
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x1 = (_ac3 * b6) >> 13;
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x2 = (_b1 * ((b6 * b6) >> 12)) >> 16;
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x3 = ((x1 + x2) + 2) >> 2;
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uint32_t b4 = (_ac4 * (uint32_t)(x3 + 32768)) >> 15;
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uint32_t b7 = ((uint32_t)up - b3) * (50000 >> _oss);
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int32_t p;
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if (b7 < 0x80000000) {
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p = (b7 << 1) / b4;
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} else {
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p = (b7 / b4) << 1;
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}
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x1 = (p >> 8) * (p >> 8);
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x1 = (x1 * 3038) >> 16;
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x2 = (-7357 * p) >> 16;
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p = p + ((x1 + x2 + 3791) >> 4);
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_pressure = p / 100.0f;
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_altitude = 44330.0f * (1.0f - powf(_pressure / SEA_LEVEL_HPA, 0.1903f));
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return true;
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}
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float getPressure() const { return _pressure; }
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float getAltitude() const { return _altitude; }
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float getTemperature() const { return _temperature; }
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bool isInitialized() const { return _initialized; }
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private:
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static constexpr uint8_t REG_CHIP_ID = 0xD0;
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static constexpr uint8_t REG_CONTROL = 0xF4;
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static constexpr uint8_t REG_OUT_MSB = 0xF6;
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static constexpr uint8_t CMD_TEMP = 0x2E;
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static constexpr uint8_t CMD_PRESSURE = 0x34;
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void writeReg(uint8_t reg, uint8_t val) { I2CBus::instance().writeReg(_addr, reg, &val, 1); }
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uint8_t readReg8(uint8_t reg) {
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uint8_t val = 0;
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I2CBus::instance().readReg(_addr, reg, &val, 1);
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return val;
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}
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int16_t readReg16(uint8_t reg) {
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uint8_t buf[2];
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I2CBus::instance().readReg(_addr, reg, buf, 2);
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return (int16_t)((buf[0] << 8) | buf[1]);
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}
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uint16_t readReg16U(uint8_t reg) {
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uint8_t buf[2];
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I2CBus::instance().readReg(_addr, reg, buf, 2);
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return (uint16_t)((buf[0] << 8) | buf[1]);
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}
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int32_t readReg24(uint8_t reg) {
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uint8_t buf[3];
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I2CBus::instance().readReg(_addr, reg, buf, 3);
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return ((int32_t)buf[0] << 16) | ((int32_t)buf[1] << 8) | buf[2];
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}
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uint8_t _addr;
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bool _initialized = false;
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uint8_t _oss = 0;
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int16_t _ac1, _ac2, _ac3;
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uint16_t _ac4, _ac5, _ac6;
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int16_t _b1, _b2;
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int16_t _mb, _mc, _md;
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float _temperature = 0;
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float _pressure = 0;
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float _altitude = 0;
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};
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