Library for BMP280 and BME280 sensor modules with emphasis on efficient single‑burst reading to minimize I²C/SPI bus usage, while maintaining full compatibility with both continuous and forced‑mode measurements.

The driver auto‑detects whether your sensor is BME280 (Temperature + Pressure + Humidity) or BMP280 (Temperature + Pressure only), then performs single‑burst reads starting at 0xF7 for minimal bus time. Works over I²C and 4‑wire SPI.

• BME280 detected (chipID = 0x60): returns T, P, H
• BMP280 detected (chipID = 0x58): returns T, P; humidity is not present

bool beginI2C(uint8_t addr=0x76, TwoWire *wire=&Wire);
bool beginSPI(uint8_t csPin, SPIClass* spi=&SPI, uint32_t spiHz=8000000UL);

void setSampling(uint8_t osrs_t=1, uint8_t osrs_p=1, uint8_t osrs_h=1,
                 uint8_t iir=0, uint8_t standby=0, uint8_t mode=MODE_NORMAL);

bool read280(float &T_c, float &P_hPa, float &H_rh);        // returns T,P,(H if present)
bool readForced280(float &T_c, float &P_hPa, float &H_rh);  // triggers one conversion then reads burst

float readAltitude(float seaLevel_hPa = 1013.25f);
uint8_t chipID() const;
bool hasHumidity() const;        // true on BME280, false on BMP280
uint8_t status() const; bool isMeasuring() const; bool isUpdatingNVM() const;

Note: On BMP280 (hasHumidity()==false), H_rh is set to NAN by read280() / readForced280().

• Mode: MODE_SLEEP (idle), MODE_FORCED (one conversion), MODE_NORMAL (continuous)
• Oversampling: 0=skip, 1=x1, 2=x2, 4=x4, 8=x8, 16=x16 (all three on BME; BMP ignores osrs_h)
• IIR filter: 0=off, 1=2, 2=4, 3=8, 4=16
• Standby (NORMAL mode only): 0=0.5ms, 1=62.5ms, 2=125ms, 3=250ms, 4=500ms, 5=1000ms, 6=10ms, 7=20ms

• VCC→3.3V, GND→GND, SDA→SDA, SCL→SCL
• Address: 0x76 (default) or 0x77 (SDO high on many boards)

• VCC→3.3V, GND→GND
• CS → your chosen digital pin (e.g., D10 on AVR)
• SCK→SCK, MOSI→MOSI (SDI), MISO→MISO (SDO)
• 3.3V logic only — level‑shift if your MCU is 5 V

Works on any Arduino‑compatible core with standard Wire/SPI and C++11 support.

Known‑good: AVR (Uno/Nano/Pro Mini/Mega/Leonardo), SAMD (Zero/MKR), RP2040 (Pico), ESP8266/ESP32, Teensy 3/4, STM32 (Arduino core), nRF52, etc.
Edge cases: very old cores lacking repeated‑start or SPI transactions; 3‑wire SPI only; 5 V logic without level shifting.

• I2C_Continuous — NORMAL mode, periodic read280()
• I2C_Forced — SLEEP + readForced280() (detailed setSampling comments)
• SPI_Continuous — NORMAL mode over SPI
• SPI_Forced — forced mode over SPI

MIT