BME280 register map

Combined humidity, pressure and temperature sensor — Bosch Sensortec

14 registers I2C, SPI I²C 0x76, 0x77 8-bit reg addresses 62% bit coverage not yet human-verified

I²C address conflict. On its default address(es) this part collides with BMP280 (0x76, 0x77); PCA9685 (0x76, 0x77). You cannot put them on the same bus without changing a strap pin, using an I²C multiplexer, or moving one to a second bus. See the full address map.

Get it as a C header

pip install regforge
regforge gen BME280 --out ./src --driver --tests

Writes bme280_regs.h with every address, mask and shift below, a bus-agnostic driver skeleton, and a file of compile-time assertions that make your compiler check the bit arithmetic. No API key needed — this part ships inside the package.

Not yet human-verified. Transcribed and mechanically validated — no overlapping fields, no out-of-range bits, reset values consistent with their fields — but not yet checked line-by-line against the datasheet. Verifying it is a useful half hour.

Registers

Addr	Register	Access	Width	Reset	Description
0xD0	CHIP_ID	RO	8	0x60	Chip identification number. Reads 0x60 on a BME280 (0x58 on a BMP280).
0xE0	RESET	WO	8	0x00	Write 0xB6 to trigger a soft reset. Any other value is ignored. Reads return 0x00.
0xF2	CTRL_HUM	RW	8	0x00	Humidity acquisition options. Changes take effect only after a write to CTRL_MEAS.
0xF3	STATUS	RO	8	0x00	Device status
0xF4	CTRL_MEAS	RW	8	0x00	Pressure and temperature acquisition options, and the sensor mode
0xF5	CONFIG	RW	8	0x00	Rate, filter and interface options. Writes are ignored in normal mode.
0xF7	PRESS_MSB	RO	8	0x80	Raw pressure, bits [19:12]
0xF8	PRESS_LSB	RO	8	0x00	Raw pressure, bits [11:4]
0xF9	PRESS_XLSB	RO	8	0x00	Raw pressure, bits [3:0] in bits [7:4]
0xFA	TEMP_MSB	RO	8	0x80	Raw temperature, bits [19:12]
0xFB	TEMP_LSB	RO	8	0x00	Raw temperature, bits [11:4]
0xFC	TEMP_XLSB	RO	8	0x00	Raw temperature, bits [3:0] in bits [7:4]
0xFD	HUM_MSB	RO	8	0x80	Raw humidity, bits [15:8]
0xFE	HUM_LSB	RO	8	0x00	Raw humidity, bits [7:0]

Bit layouts

Drawn MSB-first, the way the datasheet draws them. [7:5] means shift 5, width 3, mask 0xE0 — this is the notation that costs people a day when they read it backwards.

CTRL_HUM @ 0xF2 — 1 fields

—7

—6

—5

—4

—3

OSRS_H[2:0]

Bits	Field	Access	Mask	Reset	Description
[2:0]	OSRS_H	RW	0x07	0x00	Oversampling setting for humidity

CTRL_HUM.OSRS_H values

Value	Name	Meaning
0x00	SKIPPED	Measurement skipped, output set to 0x80000
0x01	X1	Oversampling x1
0x02	X2	Oversampling x2
0x03	X4	Oversampling x4
0x04	X8	Oversampling x8
0x05	X16	Oversampling x16

STATUS @ 0xF3 — 2 fields

—7

—6

—5

—4

MEASURING[3]

—2

—1

IM_UPDATE[0]

Bits	Field	Access	Mask	Reset	Description
[3]	MEASURING	RO	0x08	0x00	Set while a conversion is running
[0]	IM_UPDATE	RO	0x01	0x00	Set while NVM data is being copied to image registers

CTRL_MEAS @ 0xF4 — 3 fields

OSRS_T[7:5]

OSRS_P[4:2]

MODE[1:0]

Bits	Field	Access	Mask	Reset	Description
[7:5]	OSRS_T	RW	0xE0	0x00	Oversampling setting for temperature
[4:2]	OSRS_P	RW	0x1C	0x00	Oversampling setting for pressure
[1:0]	MODE	RW	0x03	0x00	Sensor operating mode

CTRL_MEAS.OSRS_T values

Value	Name	Meaning
0x00	SKIPPED	Measurement skipped, output set to 0x80000
0x01	X1	Oversampling x1
0x02	X2	Oversampling x2
0x03	X4	Oversampling x4
0x04	X8	Oversampling x8
0x05	X16	Oversampling x16

CTRL_MEAS.OSRS_P values

Value	Name	Meaning
0x00	SKIPPED	Measurement skipped, output set to 0x80000
0x01	X1	Oversampling x1
0x02	X2	Oversampling x2
0x03	X4	Oversampling x4
0x04	X8	Oversampling x8
0x05	X16	Oversampling x16

CTRL_MEAS.MODE values

Value	Name	Meaning
0x00	SLEEP	No measurements, minimum power
0x01	FORCED	One measurement, then return to sleep
0x02	FORCED_ALT	Alternate encoding of forced mode
0x03	NORMAL	Cycles between measuring and standby

CONFIG @ 0xF5 — 3 fields

T_SB[7:5]

FILTER[4:2]

—1

SPI3W_EN[0]

Bits	Field	Access	Mask	Reset	Description
[7:5]	T_SB	RW	0xE0	0x00	Inactive duration in normal mode
[4:2]	FILTER	RW	0x1C	0x00	IIR filter time constant
[0]	SPI3W_EN	RW	0x01	0x00	Enable 3-wire SPI interface

CONFIG.T_SB values

Value	Name	Meaning
0x00	0_5_MS	0.5 ms
0x01	62_5_MS	62.5 ms
0x02	125_MS	125 ms
0x03	250_MS	250 ms
0x04	500_MS	500 ms
0x05	1000_MS	1000 ms
0x06	10_MS	10 ms -- differs from the BMP280
0x07	20_MS	20 ms -- differs from the BMP280

CONFIG.FILTER values

Value	Name	Meaning
0x00	OFF	Filter off
0x01	COEFF_2	Coefficient 2
0x02	COEFF_4	Coefficient 4
0x03	COEFF_8	Coefficient 8
0x04	COEFF_16	Coefficient 16

Generated C header

What regforge gen BME280 writes for CTRL_MEAS:

/* ------------------------------------------------------------------------ */
/* CTRL_MEAS @ 0xF4u  rw  8-bit  reset 0x00u */
/* Pressure and temperature acquisition options, and the sensor mode */
/* ------------------------------------------------------------------------ */

#define BME280_CTRL_MEAS                               0xF4u
#define BME280_CTRL_MEAS_WIDTH                         8u
#define BME280_CTRL_MEAS_RESET                         0x00u

/*   OSRS_T bits [7:5] rw reset 0x00u -- Oversampling setting for temperature */
#define BME280_CTRL_MEAS_OSRS_T_SHIFT                  5u
#define BME280_CTRL_MEAS_OSRS_T_WIDTH                  3u
#define BME280_CTRL_MEAS_OSRS_T_MASK                   0xE0u
#define BME280_CTRL_MEAS_OSRS_T_GET(reg)               (((uint8_t)(reg) & 0xE0u) >> 5u)
#define BME280_CTRL_MEAS_OSRS_T_SET(reg, val)          (((uint8_t)(reg) & (uint8_t)~0xE0u) | (((uint8_t)(val) << 5u) & 0xE0u))
#define BME280_CTRL_MEAS_OSRS_T_SKIPPED                0x00u  /* Measurement skipped, output set to 0x80000 */
#define BME280_CTRL_MEAS_OSRS_T_X1                     0x01u  /* Oversampling x1 */
#define BME280_CTRL_MEAS_OSRS_T_X2                     0x02u  /* Oversampling x2 */
#define BME280_CTRL_MEAS_OSRS_T_X4                     0x03u  /* Oversampling x4 */
#define BME280_CTRL_MEAS_OSRS_T_X8                     0x04u  /* Oversampling x8 */
#define BME280_CTRL_MEAS_OSRS_T_X16                    0x05u  /* Oversampling x16 */

/*   OSRS_P bits [4:2] rw reset 0x00u -- Oversampling setting for pressure */
#define BME280_CTRL_MEAS_OSRS_P_SHIFT                  2u
#define BME280_CTRL_MEAS_OSRS_P_WIDTH                  3u
#define BME280_CTRL_MEAS_OSRS_P_MASK                   0x1Cu
#define BME280_CTRL_MEAS_OSRS_P_GET(reg)               (((uint8_t)(reg) & 0x1Cu) >> 2u)
#define BME280_CTRL_MEAS_OSRS_P_SET(reg, val)          (((uint8_t)(reg) & (uint8_t)~0x1Cu) | (((uint8_t)(val) << 2u) & 0x1Cu))
#define BME280_CTRL_MEAS_OSRS_P_SKIPPED                0x00u  /* Measurement skipped, output set to 0x80000 */
#define BME280_CTRL_MEAS_OSRS_P_X1                     0x01u  /* Oversampling x1 */
#define BME280_CTRL_MEAS_OSRS_P_X2                     0x02u  /* Oversampling x2 */
#define BME280_CTRL_MEAS_OSRS_P_X4                     0x03u  /* Oversampling x4 */
#define BME280_CTRL_MEAS_OSRS_P_X8                     0x04u  /* Oversampling x8 */
#define BME280_CTRL_MEAS_OSRS_P_X16                    0x05u  /* Oversampling x16 */

/*   MODE bits [1:0] rw reset 0x00u -- Sensor operating mode */
#define BME280_CTRL_MEAS_MODE_SHIFT                    0u
#define BME280_CTRL_MEAS_MODE_WIDTH                    2u
#define BME280_CTRL_MEAS_MODE_MASK                     0x03u
#define BME280_CTRL_MEAS_MODE_GET(reg)                 (((uint8_t)(reg) & 0x03u) >> 0u)
#define BME280_CTRL_MEAS_MODE_SET(reg, val)            (((uint8_t)(reg) & (uint8_t)~0x03u) | (((uint8_t)(val) << 0u) & 0x03u))
#define BME280_CTRL_MEAS_MODE_SLEEP                    0x00u  /* No measurements, minimum power */
#define BME280_CTRL_MEAS_MODE_FORCED                   0x01u  /* One measurement, then return to sleep */
#define BME280_CTRL_MEAS_MODE_FORCED_ALT               0x02u  /* Alternate encoding of forced mode */

Compared with

BME280 vs BMP280

Related parts

Source

Transcribed from BST-BME280-DS002 (hand-transcribed) (hand-transcribed). Hand-authored seed entry, not machine-extracted. Check against BST-BME280-DS002 before trusting it, then mark it verified.

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