ds18b20.h File Reference

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API Description

/*
 * Author: Jon Trulson <jtrulson@ics.com>
 * Copyright (c) 2016 Intel Corporation.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include <unistd.h>
#include <stdio.h>
#include <signal.h>

#include "ds18b20.h"
#include "upm_utilities.h"

bool shouldRun = true;

void sig_handler(int signo)
{
  if (signo == SIGINT)
    shouldRun = false;
}

int main(int argc, char **argv)
{
    signal(SIGINT, sig_handler);


    printf("Initializing...\n");

    // Instantiate an DS18B20 instance using the uart 0
    ds18b20_context sensor = ds18b20_init(0);

    if (!sensor)
    {
        printf("ds18b20_init() failed.\n");
        return(1);
    }

    printf("Found %d device(s)\n\n", ds18b20_devices_found(sensor));

    // update and print available values every 2 seconds
    while (shouldRun)
    {
        // update our values for all sensors
        ds18b20_update(sensor, -1);

        for (unsigned int i=0; i<ds18b20_devices_found(sensor); i++)
        {
            printf("Device %02d: Temperature: %f C\n",
                    i, ds18b20_get_temperature(sensor, i));
        }
        printf("\n");

        upm_delay(2);
    }

    printf("Exiting...\n");

    ds18b20_close(sensor);

    return 0;
}

Go to the source code of this file.

Data Structures
struct	_ds18b20_context

Functions
ds18b20_context	ds18b20_init (unsigned int uart)
void	ds18b20_close (ds18b20_context dev)
void	ds18b20_update (const ds18b20_context dev, int index)
float	ds18b20_get_temperature (const ds18b20_context dev, unsigned int index)
void	ds18b20_set_resolution (const ds18b20_context dev, unsigned int index, DS18B20_RESOLUTIONS_T res)
void	ds18b20_copy_scratchpad (const ds18b20_context dev, unsigned int index)
void	ds18b20_recall_eeprom (const ds18b20_context dev, unsigned int index)
unsigned int	ds18b20_devices_found (const ds18b20_context dev)
const uint8_t *	ds18b20_get_id (const ds18b20_context dev, unsigned int index)

Typedefs
typedef struct _ds18b20_info_t	ds18b20_info_t
typedef struct _ds18b20_context *	ds18b20_context

Function Documentation

ds18b20_context ds18b20_init

(

unsigned int

uart

)

This function will initilaize and search the 1-wire bus and store information on each DS18B20 device detected on the bus. If no devices are found, NULL is returned. Once this function completes successfully, you can use ds18b20_devices_found() to determine how many devices were detected.

Returns

device context, or NULL on error.

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void ds18b20_close

(

ds18b20_context

dev

)

Close the device and deallocate all resources.

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void ds18b20_update	(	const ds18b20_context	dev,
		int	index
	)

Update our stored temperature for a device. This method must be called prior to ds18b20_get_temperature().

Parameters

index

The device index to access (starts at 0). Specify -1 to query all detected devices. Default: -1

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float ds18b20_get_temperature	(	const ds18b20_context	dev,
		unsigned int	index
	)

Get the current temperature. ds18b20_update() must have been called prior to calling this method.

Parameters

index

The device index to access (starts at 0).

Returns

The last temperature reading in Celsius.

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void ds18b20_set_resolution	(	const ds18b20_context	dev,
		unsigned int	index,
		DS18B20_RESOLUTIONS_T	res
	)

Set the device resolution for a device. These devices support 9, 10, 11, and 12 bits of resolution, with the default from the factory at 12 bits.

Parameters

index	The device index to access (starts at 0).
res	One of the DS18B20_RESOLUTIONS_T values

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void ds18b20_copy_scratchpad	(	const ds18b20_context	dev,
		unsigned int	index
	)

Copy the device's scratchpad memory to the EEPROM. This includes the configuration byte (resolution).

Parameters

index

The device index to access (starts at 0).

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void ds18b20_recall_eeprom	(	const ds18b20_context	dev,
		unsigned int	index
	)

Copy the device's EEPROM memory to the scratchpad. This method will return when the copy completes. This operation is performed by the device automatically on power up, so it is rarely needed.

Parameters

index

The device index to access (starts at 0).

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unsigned int ds18b20_devices_found

(

const ds18b20_context

dev

)

This method will return the number of DS18B20 devices that were found on the bus by ds18b20_init().

Returns

number of DS18B20's that were found on the bus

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const uint8_t* ds18b20_get_id	(	const ds18b20_context	dev,
		unsigned int	index
	)

Return an 8 byte string representing the unique device ID (1-wire romcode) for a given device index. The pointer returned is statically allocated and will be overwritten on each call.

Parameters

index

The device index to access (starts at 0).

Returns

pointer to 8 byte DS18B20_ROMCODE_T representing the 1-wire device's unique romcode, or NULL on error.

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Typedef Documentation

typedef struct _ds18b20_context * ds18b20_context

Device context