Sandro Sole / max6675

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Fork of max6675 by Jason Engelman

max6675.cpp@4:b674a4cf4584, 2017-10-16 (annotated)

Committer:
sandrosole
Date:
Mon Oct 16 19:43:20 2017 +0000
Revision:
4:b674a4cf4584
Parent:
2:661ac326e3b3 
compatibility change

Who changed what in which revision?

UserRevisionLine numberNew contents of line
tecnosys 2:661ac326e3b3 1
tecnosys 2:661ac326e3b3 2 #include <mbed.h>
tecnosys 2:661ac326e3b3 3 #include "max6675.h"
tecnosys 2:661ac326e3b3 4
tecnosys 2:661ac326e3b3 5 max6675::max6675(SPI& _spi, PinName _ncs) : spi(_spi), ncs(_ncs) {
tecnosys 2:661ac326e3b3 6
tecnosys 2:661ac326e3b3 7 }
tecnosys 2:661ac326e3b3 8
tecnosys 2:661ac326e3b3 9 float max6675::read_temp() {
tecnosys 2:661ac326e3b3 10 short value = 0;
tecnosys 2:661ac326e3b3 11 float temp = 0;
tecnosys 2:661ac326e3b3 12
tecnosys 2:661ac326e3b3 13 uint8_t highByte=0;
tecnosys 2:661ac326e3b3 14 uint8_t lowByte=0;
tecnosys 2:661ac326e3b3 15
tecnosys 2:661ac326e3b3 16 select();
tecnosys 2:661ac326e3b3 17 wait(.25); //This delay is needed else it does'nt seem to update the temp
tecnosys 2:661ac326e3b3 18
tecnosys 2:661ac326e3b3 19 highByte = spi.write(0);
tecnosys 2:661ac326e3b3 20 lowByte = spi.write(0);
tecnosys 2:661ac326e3b3 21 deselect();
tecnosys 2:661ac326e3b3 22
tecnosys 2:661ac326e3b3 23
tecnosys 2:661ac326e3b3 24 if (lowByte & (1<<2)) {
tecnosys 2:661ac326e3b3 25 error("No Probe");
tecnosys 2:661ac326e3b3 26 } else {
tecnosys 2:661ac326e3b3 27 value = (highByte << 5 | lowByte>>3);
tecnosys 2:661ac326e3b3 28 }
tecnosys 2:661ac326e3b3 29
tecnosys 2:661ac326e3b3 30 temp = (value*0.25); // Multiply the value by 0.25 to get temp in ˚C or
tecnosys 2:661ac326e3b3 31 // * (9.0/5.0)) + 32.0; // Convert value to ˚F (ensure proper floats!)
tecnosys 2:661ac326e3b3 32
tecnosys 2:661ac326e3b3 33 return temp;
tecnosys 2:661ac326e3b3 34 }
tecnosys 2:661ac326e3b3 35
tecnosys 2:661ac326e3b3 36 void max6675::select() {
tecnosys 2:661ac326e3b3 37 ncs = 0;
tecnosys 2:661ac326e3b3 38 }
tecnosys 2:661ac326e3b3 39
tecnosys 2:661ac326e3b3 40 void max6675::deselect() {
tecnosys 2:661ac326e3b3 41 ncs = 1;
tecnosys 2:661ac326e3b3 42 }