bmp280.h File Reference

BMP280 calibration and explicit forced-conversion driver. More...

#include "nexus/core/time.h"

Go to the source code of this file.

Data Structures
struct	nx_bmp280_transport_port_t
	Synchronous settled SPI transaction port. More...
struct	nx_bmp280_calibration_t
	Register calibration, owned by one device instance. More...
struct	nx_bmp280_sample_t
	Output is valid only on successful conversion/compensation. More...
struct	nx_bmp280_t
	Explicit device context, no Board pins or automatic sampling task. More...

Functions
nx_result_t	nx_bmp280_parse_calibration (const uint8_t *bytes, size_t length, nx_bmp280_calibration_t *calibration)
	Parse the exact 24-byte little-endian calibration block.
nx_result_t	nx_bmp280_compensate (const nx_bmp280_calibration_t *calibration, uint32_t raw_temperature, uint32_t raw_pressure, nx_bmp280_sample_t *sample)
	Compensate one raw sample using checked integer arithmetic.
nx_result_t	nx_bmp280_init (nx_bmp280_t *device, nx_bmp280_transport_port_t transport, nx_time_us_t deadline)
	Validate chip ID and load calibration, without scanning.
nx_result_t	nx_bmp280_begin (nx_bmp280_t *device, nx_time_us_t deadline)
	Start one forced temperature/pressure conversion.
nx_result_t	nx_bmp280_poll (nx_bmp280_t *device, nx_bmp280_sample_t *sample)
	Poll conversion without an implicit worker or blocking delay.
void	nx_bmp280_stop (nx_bmp280_t *device)
	Stop software use after all synchronous calls have exited.

Detailed Description

BMP280 calibration and explicit forced-conversion driver.

Author

Nexus Team

Definition in file bmp280.h.

Function Documentation

nx_bmp280_begin()

nx_result_t nx_bmp280_begin	(	nx_bmp280_t *	device,
		nx_time_us_t	deadline )

Start one forced temperature/pressure conversion.

Parameters

[in,out]	device	Initialized non-measuring instance
[in]	deadline	Absolute deadline covering conversion and reads

Returns

SUCCESS, BUSY, TIMEOUT or transport error

Note

Task-only serialized driver owner; oversampling x1/x1.

nx_bmp280_compensate()

nx_result_t nx_bmp280_compensate	(	const nx_bmp280_calibration_t *	calibration,
		uint32_t	raw_temperature,
		uint32_t	raw_pressure,
		nx_bmp280_sample_t *	sample )

Compensate one raw sample using checked integer arithmetic.

Parameters

[in]	calibration	Parsed calibration
[in]	raw_temperature	Unsigned 20-bit ADC value
[in]	raw_pressure	Unsigned 20-bit ADC value
[out]	sample	Written only on success

Returns

SUCCESS, INVALID for malformed/overflow calibration or IO for disabled ADC sentinel/out-of-datasheet-range physical output

nx_bmp280_init()

nx_result_t nx_bmp280_init	(	nx_bmp280_t *	device,
		nx_bmp280_transport_port_t	transport,
		nx_time_us_t	deadline )

Validate chip ID and load calibration, without scanning.

Parameters

[out]	device	Zero-initialized unused instance
[in]	transport	Synchronous settled port and live monotonic clock
[in]	deadline	Absolute deadline for all initialization accesses

Returns

SUCCESS, BUSY for NVM update, or transport/identity error

Note

Task context; failure leaves initialized false and no borrow. Does not soft-reset the part or create a wait loop/task. Retry BUSY explicitly.

nx_bmp280_parse_calibration()

nx_result_t nx_bmp280_parse_calibration	(	const uint8_t *	bytes,
		size_t	length,
		nx_bmp280_calibration_t *	calibration )

Parse the exact 24-byte little-endian calibration block.

Parameters

[in]	bytes	Register block beginning at 0x88
[in]	length	Must be exactly 24
[out]	calibration	Written only on success

Returns

SUCCESS or INVALID for length/zero pressure divisor

nx_bmp280_poll()

nx_result_t nx_bmp280_poll	(	nx_bmp280_t *	device,
		nx_bmp280_sample_t *	sample )

Poll conversion without an implicit worker or blocking delay.

Parameters

[in,out]	device	Instance with a previously started conversion
[out]	sample	Written only on SUCCESS

Returns

SUCCESS, BUSY while converting, TIMEOUT or transport error

Note

Task-only. Every port call releases temporary buffers before return. BUSY retains device conversion state, never stack or caller buffers. After terminal failure, begin may retry; the external owner chooses policy.

nx_bmp280_stop()

void nx_bmp280_stop

(

nx_bmp280_t *

device

)

Stop software use after all synchronous calls have exited.

Parameters

[in,out]

device

Quiesced driver instance

Note

Does not power off or reset a physical part. Sensor-internal conversion can finish without accessing MCU storage. No MCU borrow remains.