'**********************************************************************
'
'*****____MAX31855 type "K" T/C reader____******
'*****____Walt McDonald 1/13/15_CopyRight_________******
'-----____For use with the MAX31855 break-out board (Adafruit) with on board Voltage Reg. and Vin pin..This replaces the MAX6675
'!!!!!!!---NOTE---USE THE Vin PIN FOR USE WITH A 5volt STAMP, NOT THE 3.3Volt PIN!!!!!!---cs,so, and Clk pins are good for 6.3volts MAX.
'
' {$STAMP BS2p}        This code should run on any BS2xx stamp, Change directive to fit your stamp
' {$PBASIC 2.5}
'
'**********_This MAX81855/MAX6675(upgrade) works great from 0`C to 1025`C.,With a 1/4% accuracy full scale. <>(0.25%)_*******************************
'****************_______It does NOT READ below 0`C._****************************************************************************************
'*****___TESTED___Accuracy check with Fluke 724 Temp. Calibrator...Last Cal. 10/29/14, Good until 10/29/15_*********************************
'*****___Added T/C Fault_1/22/15__WMc___

CS              PIN     0                       ' chip select
so              PIN     1                       ' serial-out/data pin
Clk             PIN     2                       ' clock pin

MAX_T           VAR     Word                    ' MAX31855 C` result
F_temp          VAR     Word                    ' Buffer for C` to F` conversion.


Setup:
  HIGH CS                                       ' set to converion mode. MAX6675
  PAUSE 250                                     ' time to start first converion. (250 mS)

Main:
  DO
    LOW CS                                      ' set the MAX31855 to write mode, Stops all conversions
    SHIFTIN so, Clk, MSBPOST, [MAX_T\11]        ' shift in the data, MSB first on the falling clock pulse\16 bits of data only 11 are needed.
    HIGH CS                                     ' Restart conversion mode
    F_temp = (ABS MAX_T) * 9 / 5 + 32           ' Convert C` to F` This is far easier than using C * 1.8 + 32 !!!
    DEBUG CLS
    DEBUG BIN ? MAX_T                           ' Show BIN%
    DEBUG DEC ? MAX_T                           ' Show C`
    DEBUG DEC ? F_temp                          ' show conversion result
    PAUSE 1000                                  ' Allow a second for the MAX31855 to read the T/C and do the conversion.
                                                ' This PAUSE value could be less but the flash on the DEBUG screen is annoying.
    IF F_temp > 3000 THEN GOSUB Fault

  LOOP                                          ' repeat
  END

Fault:
   DEBUG CLS, "T/C fault "                      ' The MAX31855 has a fault bit(2) for this, But the simple "IF-Then" is so much easier to use.
   PAUSE 5000                                   ' The fault is either OPEN T/C, OVER TEMP (above 1025`C), or BELOW ZERO C`.
   RETURN