max6675_2.cpp

00001 
00002 #include <mbed.h>
00003 #include "max6675_2.h"
00004 
00005 max6675_2::max6675_2(SPI& _spi_2, PinName _ncs_2) : spi_2(_spi_2), ncs_2(_ncs_2) {
00006 
00007 }
00008 
00009 float max6675_2::read_temp_2() {
00010     short value_2 = 0;
00011     float temp_2 = 0;
00012     
00013     uint8_t highByte_2=0;
00014     uint8_t lowByte_2=0;
00015     
00016     select_2();
00017     wait(.25); //This delay is needed else it does'nt seem to update the temp
00018 
00019     highByte_2 = spi_2.write(0);
00020     lowByte_2 = spi_2.write(0);
00021     deselect_2();
00022 
00023 
00024     if (lowByte_2 & (1<<2)) {
00025         error("No Probe");
00026     } else {
00027         value_2 = (highByte_2 << 5 | lowByte_2>>3);
00028     }
00029 
00030     temp_2 = (value_2*0.25); // Multiply the value by 0.25 to get temp in ˚C or
00031                          //  * (9.0/5.0)) + 32.0;   // Convert value to ˚F (ensure proper floats!)
00032 
00033 return temp_2;
00034 }
00035 
00036 void max6675_2::select_2() {
00037     ncs_2 = 0;
00038 }
00039 
00040 void max6675_2::deselect_2() {
00041     ncs_2 = 1;
00042 }