DS18B20

The DS18B20 is a 1-Wire digital temperature sensor from Maxim IC.

The sensor reports degrees C with 9 to 12-bit precision from -55C to 125C (+/- 0.5C).

Each sensor has a unique 64-Bit Serial number etched into it. This allows for a number of sensors to be used on one data bus. This sensor is used in many data-logging and temperature control projects.

Reading the temperature from a DS18B20 takes up to 750ms(max).

To use the DS18B20 driver the following is required to added to the GCBASIC source file.

    #include <DS18B20.h>

Note the GCBASIC commands do not work with the older DS1820 or DS18S20 as they have a different internal resolution.

These commands are not designed to be used with parasitically powered DS18B20 sensors.

Command Usage Returns

ReadDigitalTemp

Returns two global variables.  As follows:

DSint the integer value read from the sensors DSdec the string value read from the sensors

Byte variables: DSint

String variable: DSdec

ReadTemp

ReadTemp is a function that returns the raw value of the sensor.

The temperature is read back in whole degree steps, and the sensor operates from -55 to + 125 degrees Celsius.; &#160Note that bit 7 is 0 for positive temperature values and 1 for negative values (ie negative values will appear as 128 + numeric value).

Word variable via the ReadTemp() function

ReadTemp12

ReadTemp is a function that returns the raw 12bit value of the sensor.

The temperature is read back as the raw 12 bit data into a word variable (0.0625 degree resolution).; &#160The user must interpret the data through mathematical manipulation. See the DS18B20 datasheet for more information on the 12 bit temperature/data information construct.

Word variable via the ReadTemp12() function



For more help, see ReadDigitalTemp, ReadTemp or ReadTemp12

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