Driver for the LM75 and TMP1075 temperature sensors. More...

Detailed Description

Driver for the LM75 and TMP1075 temperature sensors.

Author: Vitor Batista vitor.nosp@m..bat.nosp@m.ista@.nosp@m.ml-p.nosp@m.a.com

Definition in file lm75.h.

#include <errno.h>
#include <stdbool.h>
#include "periph/gpio.h"
#include "periph/i2c.h"

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Go to the source code of this file.

Data Structures
struct	lm75_properties
	Temperature reading properties/resolutions struct of the LM75 sensors. More...

struct	lm75_params
	Parameters required for initialization. More...

struct	lm75
	LM75 device descriptor. More...

Typedefs
typedef struct lm75_properties	lm75_properties_t
	Temperature reading properties/resolutions struct of the LM75 sensors.

typedef struct lm75_params	lm75_params_t
	Parameters required for initialization.

typedef struct lm75	lm75_t
	LM75 device descriptor.

Functions
int	lm75_init (lm75_t dev, const lm75_params_t params)
	Initialization of the LM75 sensor.

int	lm75_get_temperature_raw (const lm75_t dev, int32_t temperature)
	Temperature values of LM75 sensor.

int	lm75_get_temperature (const lm75_t dev, int32_t temperature)
	Temperature values of LM75 sensor.

int	lm75_set_temp_limits (const lm75_t dev, int32_t temp_hyst, int32_t temp_os, gpio_cb_t cb, void arg)
	Sets the values for Overtemperature Shutdown (OS) and Hysteresis Temperature (HYST).

int	lm75_get_os_temp (const lm75_t dev, int32_t temperature)
	Overtemperature Shutdown (OS) value of the LM75 sensor.

int	lm75_get_hyst_temp (const lm75_t dev, int32_t temperature)
	Hysteresis Temperature (HYST) value of the LM75 sensor.

int	lm75_get_os_pin (const lm75_t dev, bool os_pin_state)
	Read the current state of the OS pin to see if it's active.

int	lm75_poweroff (const lm75_t *dev)
	Activate the LM75 sensor shutdown mode.

int	lm75_poweron (const lm75_t *dev)
	Deactivate the LM75 sensor shutdown mode.

int	tmp1075_one_shot (const lm75_t *dev)
	Activates one shot conversion mode.

int	lm75_low_power_mode (const lm75_t *dev, uint16_t interval)
	Activates low power mode operation.

Variables
lm75_properties_t	lm75a_properties
	declaration present in lm75.c

lm75_properties_t	tmp1075_properties
	declaration present in lm75.c

Backwards compatible LM75 return values
Deprecated Use `errno` directly instead
#define	LM75_SUCCESS 0
	Success.

#define	LM75_ERROR_I2C (-EIO)
	I2C communication error.

#define	LM75_ERROR (-EINVAL)
	Other error.

Macro Definition Documentation

◆ LM75_ERROR

#define LM75_ERROR (-EINVAL)

Other error.

Definition at line 42 of file lm75.h.

◆ LM75_ERROR_I2C

#define LM75_ERROR_I2C (-EIO)

I2C communication error.

Definition at line 41 of file lm75.h.

◆ LM75_SUCCESS

#define LM75_SUCCESS 0

Success.

Definition at line 40 of file lm75.h.

Function Documentation

◆ lm75_get_hyst_temp()

int lm75_get_hyst_temp	(	const lm75_t *	dev,
		int32_t *	temperature )

Hysteresis Temperature (HYST) value of the LM75 sensor.

Reads the sensor hysteresis temperature value from THYST_REG in ºC.

Parameters

[in]	dev	device structure
[out]	temperature	buffer that the HYST temperature value will be written to

Return values

0	success
<0	Error from I2C, see i2c_read_reg

◆ lm75_get_os_pin()

int lm75_get_os_pin	(	const lm75_t *	dev,
		bool *	os_pin_state )

Read the current state of the OS pin to see if it's active.

Reads the configuration register to see the OS pin's polarity and then reads its state. Then outputs if the pin is active and whether it's in the low and active or high and active.

Parameters

[in]	dev	device structure
[out]	os_pin_state	pointer to the state of the OS pin - 0 for inactive and 1 for active

Return values

0	success
<0	Error from I2C, see i2c_read_reg

◆ lm75_get_os_temp()

int lm75_get_os_temp	(	const lm75_t *	dev,
		int32_t *	temperature )

Overtemperature Shutdown (OS) value of the LM75 sensor.

Reads the sensor OS temperature value from TOS_REG in ºC.

Parameters

[in]	dev	device structure
[out]	temperature	buffer that the OS temperature value will be written to

Return values

0	success
<0	Error from I2C, see i2c_read_reg

◆ lm75_get_temperature()

int lm75_get_temperature	(	const lm75_t *	dev,
		int32_t *	temperature )

Temperature values of LM75 sensor.

Gets the device's temperature register with the lm75_get_temperature_raw function and then returns the values in mºC, truncating values smaller than this, if available.

Parameters

[in]	dev	device structure
[out]	temperature	that the temperature value will be written to in mºC

Return values

0	success
<0	Error from I2C, see i2c_read_reg

◆ lm75_get_temperature_raw()

int lm75_get_temperature_raw	(	const lm75_t *	dev,
		int32_t *	temperature )

Temperature values of LM75 sensor.

Reads the sensor temperature values from TEMP_REG. The value is given with the full precision the device is capable of. If divided by the device's temp_mult property, the result will be the temperature in ºC and the remainder of that division will be the decimal part of the temperature, at the maximum resolution the device is capable of.

Parameters

[in]	dev	device structure
[out]	temperature	buffer that the temperature value will be written to

Return values

0	success
<0	Error from I2C, see i2c_read_reg

◆ lm75_init()

int lm75_init	(	lm75_t *	dev,
		const lm75_params_t *	params )

Initialization of the LM75 sensor.

Initializes the sensor according to the specified input parameters.

Parameters

[out]	dev	device structure to initialize
[in]	params	initialization parameters

Return values

0	success
-EINVAL	Not an LM75 or TMP1075 sensor (value in ID register does not match)
<0	Error from I2C, see i2c_read_reg

◆ lm75_low_power_mode()

int lm75_low_power_mode	(	const lm75_t *	dev,
		uint16_t	interval )

Activates low power mode operation.

This function makes the device measure temperatures in a strictly discrete way at a user definable rate, as opposed to performing continuous measurements at the device's conversion rate.

It allows the device to stay in shutdown mode for the most part, therefore consuming less power. In the TMP1075 and other devices which have the one shot feature this is done automatically. In the LM75A sensor and other sensors which lack the one shot mode feature this is done manually by switching the device to and from shutdown mode and staying awake at least long enough to perform one measurement.

Parameters

[in]	dev	device structure
[in]	interval	time interval in ms between measurements

Return values

0	success
<0	Error from I2C, see i2c_read_reg

◆ lm75_poweroff()

int lm75_poweroff ( const lm75_t * dev )

Activate the LM75 sensor shutdown mode.

Parameters

[in] dev device structure to set into shutdown mode

Return values

0	success
<0	Error from I2C, see i2c_read_reg

◆ lm75_poweron()

int lm75_poweron ( const lm75_t * dev )

Deactivate the LM75 sensor shutdown mode.

Parameters

[in] dev device structure to wake up from shutdown mode

Return values

0	success
<0	Error from I2C, see i2c_read_reg

◆ lm75_set_temp_limits()

int lm75_set_temp_limits	(	const lm75_t *	dev,
		int32_t	temp_hyst,
		int32_t	temp_os,
		gpio_cb_t	cb,
		void *	arg )

Sets the values for Overtemperature Shutdown (OS) and Hysteresis Temperature (HYST).

OS gives the temperature's upper bound and HYST the lower bound. The values are rounded to the lowest value that the device supports.

Parameters

[in]	dev	device structure
[in]	temp_hyst	desired HYST temperature in mºC
[in]	temp_os	desired OS temperature in mºC
[in]	cb	callback that is called from interrupt context
[in]	arg	optional arguments for the gpio_init_int function

Return values

0	success
-EINVAL	Invalid hysteresis or invalid GPIO config
<0	Error from I2C, see i2c_read_reg

◆ tmp1075_one_shot()

int tmp1075_one_shot ( const lm75_t * dev )

Activates one shot conversion mode.

Wakes from shutdown mode, does a single temperature conversion and writes in into the temperature register and then goes back into shutdown.

Parameters

[in] dev device structure

Return values

0	success
-ENOTSUP	feature not supported by hardware variant used
<0	Error from I2C, see i2c_read_reg

Detailed Description

Data Structures

Typedefs

Functions

Variables

Backwards compatible LM75 return values

Macro Definition Documentation

◆ LM75_ERROR

◆ LM75_ERROR_I2C

◆ LM75_SUCCESS

Function Documentation

◆ lm75_get_hyst_temp()

◆ lm75_get_os_pin()

◆ lm75_get_os_temp()

◆ lm75_get_temperature()

◆ lm75_get_temperature_raw()

◆ lm75_init()

◆ lm75_low_power_mode()

◆ lm75_poweroff()

◆ lm75_poweron()

◆ lm75_set_temp_limits()

◆ tmp1075_one_shot()