DS18 temperature sensor driver

Driver interface for the DS18 temperature sensors More...

Detailed Description

Driver interface for the DS18 temperature sensors

This driver provides [S]ensor [A]ctuator [U]ber [L]ayer capabilities. Currently the driver has the following limitations:

• Does not allow addressing devices, only supports a single device on the bus.
• The 1-Wire bus handling is hardcoded to the driver.

• Does not allow configuration of sampling width.

  Note

  Due to timing issues present on some boards this drivers features two ways of reading information from the sensor. The optimized uses accurate delays to handle this, while the second way polls the line for changes. If you know that your board can handle ~3us resolution with the xtimer module, then the optimized way is recommended. To used the optimized way add the ds18_optimized module. Also this driver test application has a whitelist of the boards this driver has been tested on and known to work.

Files
file	ds18_internal.h
	Internal addresses, registers, constants for DS1822 and DS18B20 temperature sensors.
file	ds18_params.h
	Default configuration for DS1822 and DS18B20 temperature sensors.
file	ds18.h
	Driver for Maxim Integrated DS1822 and DS18B20 temperature sensors.

Data Structures
struct	ds18_params_t
	Device initialization parameters. More...
struct	ds18_t
	Device descriptor for a ds18 device. More...

Functions
int	ds18_init (ds18_t *dev, const ds18_params_t *params)
	Initialize a ds18 device.
int	ds18_trigger (const ds18_t *dev)
	Triggers a temperature conversion.
int	ds18_read (const ds18_t *dev, int16_t *temperature)
	Reads the scratchpad for the last conversion.
int	ds18_get_temperature (const ds18_t *dev, int16_t *temperature)
	convenience function for triggering a conversion and reading the value

ds18 status return codes
#define	DS18_OK   (0)
#define	DS18_ERROR   (-1)

Macro Definition Documentation

DS18_ERROR

#define DS18_ERROR   (-1)

Definition at line 54 of file ds18.h.

DS18_OK

#define DS18_OK   (0)

Definition at line 53 of file ds18.h.

Function Documentation

ds18_get_temperature()

int ds18_get_temperature	(	const ds18_t *	dev,
		int16_t *	temperature )

convenience function for triggering a conversion and reading the value

Note

This function will block for the conversion time. The current implementation of the driver uses 12-bit resolution, so this time is 750 ms.

Parameters

[in]	dev	device descriptor
[out]	temperature	buffer to write the temperature in centi-degrees

Returns

0 on success

-1 on error

ds18_init()

int ds18_init	(	ds18_t *	dev,
		const ds18_params_t *	params )

Initialize a ds18 device.

Parameters

[out]	dev	device descriptor
[in]	params	ds18 initialization struct

Returns

0 on success

-1 on error

ds18_read()

int ds18_read	(	const ds18_t *	dev,
		int16_t *	temperature )

Reads the scratchpad for the last conversion.

Parameters

[in]	dev	device descriptor
[out]	temperature	buffer to write the temperature in centi-degrees

Returns

0 on success

-1 on error

ds18_trigger()

int ds18_trigger

(

const ds18_t *

dev

)

Triggers a temperature conversion.

Note

This also triggers a conversion on all devices connected to the bus

Parameters

[in]

dev

device descriptor

Returns

0 on success

-1 on error