Thermometer on MAX6675

[Vladimir]

Hello!
I want to share a small example of working with a thermocouple on the MAX6675. I used hardware SPI and dynamic indication on a seven-segment indicator. I assembled a device for measuring the temperature in the oven.

'Chip settings
  #chip 16LF1829, 16
  #config Osc = Int

  SPIMode MasterSlow

  DIM Temperature as Word ' Temperature value from thermocouple
  DIM SegmentsBuffer(3) as Byte ' Symbol buffer for display on the indicator
  DIM Symbols(13) ' Character values ​​from 0 to 9, empty, E, r
  Symbols = 111, 40, 31, 62, 120, 118, 119, 44, 127, 126, 0, 87, 17
  #define SymbolE 11 
  #define SymbolR 12 
  #define Clear 10   
  #define delay 5    ' Time to display one character
  DIM L_byte as Byte
  DIM Timer as Byte

  ' SPI
  #define CS  PortA.5
  #define SCK PortB.6
  #define SO  PortB.4
  Dir SO in
  Dir SCK out
  Dir CS out
  ' 7 Segments
  #define SEG1 PORTA.4
  #define SEG2 PORTA.2
  #define SEG3 PORTB.5
  Dir PORTC out
  Dir SEG1 out
  Dir SEG2 out
  Dir SEG3 out

  Wait 1 s

  Timer = 100

  do Forever

    if Timer = 100 then
      call GetTemperature
      Timer = 0
    end if
    call ShowSegments
    Timer = Timer + 1

  Loop


  Sub GetTemperature

    CS = 0
    SPITransfer 0, Temperature
    Temperature = FnLSL(Temperature, 8)
    SPITransfer 0, L_byte
    Temperature = Temperature or L_byte
    Temperature = FnLSR(Temperature, 5)
    CS = 1

  End Sub

  Sub ShowSegments
    if Temperature = 1023 then
      SegmentsBuffer(1) = SymbolE
      SegmentsBuffer(2) = SymbolR
      SegmentsBuffer(3) = SymbolR
    else if Temperature > 99 then
      SegmentsBuffer(1) = Temperature / 100
      SegmentsBuffer(2) = Temperature % 100
      SegmentsBuffer(2) = SegmentsBuffer(2) / 10
      SegmentsBuffer(3) = Temperature % 10
    else if Temperature > 9 then
      SegmentsBuffer(1) = Clear
      SegmentsBuffer(2) = Temperature / 10
      SegmentsBuffer(3) = Temperature % 10
    else
      SegmentsBuffer(1) = Clear
      SegmentsBuffer(2) = Clear
      SegmentsBuffer(3) = Temperature
    end if
    PORTC = Symbols(SegmentsBuffer(1)+1)
    Set SEG1 Off
    Set SEG3 On
    Wait delay ms
    PORTC = Symbols(SegmentsBuffer(2)+1)
    Set SEG3 Off
    Set SEG2 On
    Wait delay ms
    PORTC = Symbols(SegmentsBuffer(3)+1)
    Set SEG2 Off
    Set SEG1 On
    Wait delay ms

  End Sub

[Anobium]

A very nice implementation. I really like the use of the symbols array.

Can I lift from the forum and include in the demo folders?

[Anobium]

See https://github.com/GreatCowBASIC/Demonstration_Sources/tree/main/Temperature_Sensor_Solutions/MAX6675_Thermometer_Solutions

:-)

[Vladimir]

I'll be glad if it's useful to someone :)

[Anobium]

I am sure it will be. Your methods are worth it!