fix #21 move constructor code to begin() - breaking change (#22)

* fix #21 breaking change
* move constructor code to begin()
* fix examples
* removed "premature" return from read() so internal and temperature are always converted from raw data.

LICENSE

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2014-2021 Rob Tillaart
+Copyright (c) 2014-2022 Rob Tillaart
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

MAX31855.cpp

@@ -1,12 +1,15 @@
 //
 //    FILE: MAX31855.cpp
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.3.0
+// VERSION: 0.4.0
 // PURPOSE: Arduino library for MAX31855 chip for K type thermocouple
 //    DATE: 2014-01-01
 //     URL: https://github.com/RobTillaart/MAX31855_RT
 //
 //  HISTORY:
+//  0.4.0   2021-12-09  fix #21 breaking change for HW SPI
+//                      move constructor code to begin()
+//                      read() removed "premature" return on status.
 //  0.3.0   2021-08-11  VSPI / HSPI support for ESP32
 //                      add setGIOpins - ESP32 specific
 //                      add get/setSPIspeed() - all
@@ -33,18 +36,23 @@
 #include "MAX31855.h"
 
 
-MAX31855::MAX31855(const uint8_t select)
+MAX31855::MAX31855()
 {
-  MAX31855(255, select, 255);
 }
 
 
-MAX31855::MAX31855(const uint8_t clock, const uint8_t select, const uint8_t miso)
+void MAX31855::begin(const uint8_t select)
 {
-  _clock       = clock;
-  _select      = select;
-  _miso        = miso;
-  _hwSPI       = (clock == 255);
+  begin(255, select, 255);
+}
+
+
+void MAX31855::begin(const uint8_t clock, const uint8_t select, const uint8_t miso)
+{
+  _clock        = clock;
+  _miso         = miso;
+  _select       = select;
+  _hwSPI        = (_clock == 255);
 
   _lastTimeRead = 0;
   _offset       = 0;
@@ -53,16 +61,11 @@ MAX31855::MAX31855(const uint8_t clock, const uint8_t select, const uint8_t miso
   _temperature  = MAX31855_NO_TEMPERATURE;
   _internal     = MAX31855_NO_TEMPERATURE;
   _rawData      = 0;
-}
-
+  setSPIspeed(1000000);
 
-void MAX31855::begin()
-{
   pinMode(_select, OUTPUT);
   digitalWrite(_select, HIGH);
 
-  _spi_settings = SPISettings(_SPIspeed, MSBFIRST, SPI_MODE0);
-
   if (_hwSPI)
   {
     #if defined(ESP32)
@@ -110,7 +113,8 @@ void MAX31855::setGPIOpins(uint8_t clock, uint8_t miso, uint8_t mosi, uint8_t se
   pinMode(_select, OUTPUT);
   digitalWrite(_select, HIGH);
 
-  mySPI->end();  // disable SPI
+  //  disable SPI and enable again
+  mySPI->end();
   mySPI->begin(clock, miso, mosi, select);
 }
 #endif
@@ -130,7 +134,7 @@ uint8_t MAX31855::read()
   //      31  SIGN
   uint32_t value = _read();
 
-  if (value == 0xFFFFFFFF)  // needs a pull up on miso pin to work properly!
+  if (value == 0xFFFFFFFF)  // needs a pull up on MISO pin to work properly!
   {
     // bit 3 and bit 17 should always be 0 - P10 datasheet
     _status = STATUS_NO_COMMUNICATION;
@@ -139,12 +143,12 @@ uint8_t MAX31855::read()
 
   _lastTimeRead = millis();
 
-  // process status bit 0-2
+  //  process status bit 0-2
   _status = value & 0x0007;
-  if (_status != STATUS_OK)
-  {
-    return _status;
-  }
+  // if (_status != STATUS_OK)  // removed in 0.4.0 as internal can be valid.
+  // {
+  //   return _status;
+  // }
 
   value >>= 3;
 
@@ -233,3 +237,4 @@ float MAX31855::getTemperature()
 
 
 // -- END OF FILE --
+

MAX31855.h

@@ -2,7 +2,7 @@
 //
 //    FILE: MAX31855.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.3.0
+// VERSION: 0.4.0
 // PURPOSE: Arduino library for MAX31855 chip for K type thermocouple
 //    DATE: 2014-01-01
 //     URL: https://github.com/RobTillaart/MAX31855_RT
@@ -25,7 +25,7 @@
 #include "SPI.h"
 
 
-#define MAX31855_VERSION              (F("0.3.0"))
+#define MAX31855_VERSION              (F("0.4.0"))
 
 #define MAX31855_NO_TEMPERATURE       -999
 
@@ -63,12 +63,13 @@
 class MAX31855
 {
 public:
-  // HW SPI
-  MAX31855(uint8_t select);
-  // SW SPI
-  MAX31855(uint8_t clock, uint8_t select, uint8_t miso);
 
-  void     begin();
+  MAX31855();
+
+  //  HW SPI
+  void     begin(uint8_t select);
+  //  SW SPI
+  void     begin(uint8_t clock, uint8_t select, uint8_t miso);
 
   // returns state - bit field: 0 = STATUS_OK
   uint8_t  read();
@@ -128,7 +129,7 @@ class MAX31855
   uint8_t  _miso;
   uint8_t  _select;
 
-  uint32_t    _SPIspeed = 1000000;
+  uint32_t    _SPIspeed;
   SPIClass    * mySPI;
   SPISettings _spi_settings;
   #if defined(ESP32)

README.md

@@ -5,11 +5,12 @@
 [![License: MIT](https://img.shields.io/badge/license-MIT-green.svg)](https://github.com/RobTillaart/MAX31855_RT/blob/master/LICENSE)
 [![GitHub release](https://img.shields.io/github/release/RobTillaart/MAX31855_RT.svg?maxAge=3600)](https://github.com/RobTillaart/MAX31855_RT/releases)
 
+
 # MAX31855_RT
 
 Arduino library for MAX31855 chip for K type thermocouple.
 
-The library has experimental support for other types of thermocouples E, J, N, R, S, T
+The library has experimental support for other types of thermocouples E, J, N, R, S, T.
 
 
 ## Description
@@ -42,11 +43,11 @@ Library tested with breakout board
 Default pin connections. ESP32 can overrule with **setGPIOpins()**.
 
  | HW SPI   |  UNO  |  ESP32 VSPI |  ESP32 HSPI | Notes
- |:---------|:-----:|:-------:|:-------:|:----------|
- | CLOCKPIN |   13  |   18    |   14    |
- | MISO     |   12  |   19    |   12    |
- | MOSI     |   11  |   23    |   13    |  *not used...*
- | SELECT   | eg. 4 |    5    |   15    |  *can be others too.*
+ |:---------|:-----:|:-----------:|:-----------:|:----------|
+ | CLOCKPIN |   13  |   18        |   14        |
+ | MISO     |   12  |   19        |   12        |
+ | MOSI     |   11  |   23        |   13        |  *not used...*
+ | SELECT   | eg. 4 |    5        |   15        |  *can be others too.*
 
 
 Performance read() function, timing in us.  (ESP32 @240MHz)
@@ -67,16 +68,17 @@ Performance read() function, timing in us.  (ESP32 @240MHz)
 
 ### Constructor
 
-- **MAX31855(const uint8_t select)** create object and set select pin => hardware SPI
-- **MAX31855(const uint8_t sclk, const uint8_t select, const uint8_t miso)** create object, set clock, select and miso pin => software SPI
+- **MAX31855()** create object.
+- **void begin(const uint8_t select)** set select pin => hardware SPI
+- **void begin(const uint8_t sclk, const uint8_t select, const uint8_t miso)** set clock, select and miso pin => software SPI
 
 
 ### Hardware SPI
 
 To be used only if one needs a specific speed.
 
-- **void setSPIspeed(uint32_t speed)** set SPI transfer rate
-- **uint32_t getSPIspeed()** returns SPI transfer rate
+- **void setSPIspeed(uint32_t speed)** set SPI transfer rate.
+- **uint32_t getSPIspeed()** returns SPI transfer rate.
 
 
 ### ESP32 specific
@@ -228,6 +230,11 @@ or
 
 See examples
 
+#### breaking change 0.4.0 
+
+In issue #21 it became clear that the code in the constructor is not always executed correctly.
+Therefore this code + parameters is moved to the **Begin()** function.
+
 
 ## Experimental part (to be tested)
 

examples/Demo_getRawData/Demo_getRawData.ino

@@ -1,27 +1,30 @@
 //
 //    FILE: Demo_getRawData.ino
 //  AUTHOR: FabioBrondo
-// VERSION: 0.1.1
+// VERSION: 0.4.0
 // PURPOSE: thermocouple lib demo application
 //    DATE: 2020-08-24
 //     URL: https://github.com/RobTillaart/MAX31855_RT
 //
 
+
 #include <SPI.h>
 #include <MAX31855.h>
 
+
 #define MAXDO     7 // Defining the MISO pin
 #define MAXCS     6 // Defining the CS pin
 #define MAXCLK    5 // Defining the SCK pin
 
 
-MAX31855 thermocouple(MAXCLK, MAXCS, MAXDO);
+MAX31855 thermocouple;
+
 
 void setup ()
 {
   Serial.begin(115200);
   delay(250);
-  thermocouple.begin();
+  thermocouple.begin(MAXCLK, MAXCS, MAXDO);
 }
 
 
@@ -52,4 +55,6 @@ void loop ()
   delay(100);
 }
 
+
 // -- END OF FILE --
+

examples/max31855_ESP32_HSPI/.arduino-ci.yml

@@ -5,3 +5,4 @@ compile:
     # - leonardo
     # - due
     # - zero
+    - esp32

examples/max31855_ESP32_HSPI/max31855_ESP32_HSPI.ino

@@ -11,6 +11,7 @@
 // one might to need to disconnect pin 12 during upload of the code
 // when HSPI is used.
 
+
 #include "MAX31855.h"
 
 
@@ -35,8 +36,7 @@ const int csPin   = 15;
 
 uint32_t start, stop;
 
-
-MAX31855 tc(csPin);
+MAX31855 tc;
 
 
 void setup()
@@ -49,8 +49,11 @@ void setup()
   Serial.println();
 
   tc.selectHSPI();     // needs to be called before begin()
-  tc.begin();
-  tc.setSPIspeed(16000000);
+
+  tc.begin(csPin);
+  // tc.begin(14, csPin, 12);  // SW SPI for testing
+
+  tc.setSPIspeed(1000000);
 }
 
 
@@ -90,3 +93,4 @@ void loop()
 
 
 // -- END OF FILE --
+

examples/max31855_ESP32_VSPI/.arduino-ci.yml

@@ -5,3 +5,4 @@ compile:
     # - leonardo
     # - due
     # - zero
+    - esp32

examples/max31855_ESP32_VSPI/max31855_ESP32_VSPI.ino

@@ -29,12 +29,12 @@
 // | MOSI     |   11  |   23    |   13    |  * not used...
 // | SELECT   | eg. 4 |    5    |   15    |  * can be others too.
 
-const int csPin   = 15;
+const int csPin   = 25;
 
 uint32_t start, stop;
 
 
-MAX31855 tc(csPin);
+MAX31855 tc;
 
 
 void setup()
@@ -47,7 +47,10 @@ void setup()
   Serial.println();
 
   tc.selectVSPI();     // needs to be called before begin()
-  tc.begin();
+
+  tc.begin(csPin);
+  // tc.begin(14, csPin, 12);  // SW SPI for testing
+
   tc.setSPIspeed(16000000);
 }
 
@@ -88,3 +91,4 @@ void loop()
 
 
 // -- END OF FILE --
+

examples/max31855_array/max31855_array.ino

@@ -15,15 +15,18 @@
 const int dataPin  = 7;
 const int clockPin = 6;
 
-MAX31855 sensors[] =
+
+MAX31855 A, B, C;
+
+MAX31855 sensors[] = 
 {
-  MAX31855(clockPin, 5, dataPin),
-  MAX31855(clockPin, 4, dataPin),
-  MAX31855(clockPin, 3, dataPin)
+  A, B, C
 };
 
+
 const uint8_t sensorCount = sizeof(sensors) / sizeof(MAX31855);
 
+
 void setup()
 {
   Serial.begin(115200);
@@ -35,10 +38,11 @@ void setup()
 
   for (int i = 0; i < sensorCount; i++)
   {
-    sensors[i].begin();
+    sensors[i].begin(clockPin, 3 + i, dataPin);  //  three different select pins.
   }
 }
 
+
 void loop()
 {
   Serial.print("\tTime:\t");
@@ -66,4 +70,6 @@ void loop()
   delay(1000);
 }
 
+
 // -- END OF FILE --
+