Tiit Rätsep / MAX31855

Library for MAX31855. Based on MAX6675 library. I have only implemented the temperature reading. The chip supports also the reading of internal reference temperature and faults for shorted thermocouple and shorts to vcc/gnd.

MAX31855.cpp@0:a07644a18427, 2012-03-10 (annotated)

Committer:
ratsept
Date:
Sat Mar 10 19:30:40 2012 +0000
Revision:
0:a07644a18427

        

        
Who changed what in which revision?

        

            
                
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#include <mbed.h>





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#include "MAX31855.h"





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 MAX31855::MAX31855(SPI& _spi, PinName _ncs) : spi(_spi), ncs(_ncs)





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{





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    deselect();





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}





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float MAX31855::read_temp()





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{





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    short value = 0;





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    float temp = 0;





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    int16_t response = 0;





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    uint8_t resp_byte = 0;





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    select();





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    resp_byte = spi.write(0);





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    response |= resp_byte << 8;





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    resp_byte = spi.write(0);





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    response |= resp_byte << 0;





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    deselect();





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    if (response & 0x0001)





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    {





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        error("Error");





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        return 2000.0;





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    }





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    response &= 0xfffc; // mask lower two bits





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    temp = response / 16.0;





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    return temp;





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}





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void MAX31855::select()





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{





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    ncs = 0;





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}





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void MAX31855::deselect()





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{





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    ncs = 1;





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}