Revision 2:b42b7148fbe0, committed 2019-03-29

Comitter:

freakone

Date:

Fri Mar 29 14:09:06 2019 +0000

Parent:

1:f5d6dfd8b4a6

Commit message:

new library content and calculations

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MAX31865.cpp	Fri Mar 29 14:09:06 2019 +0000
@@ -0,0 +1,179 @@
+#include "MAX31865.h"
+
+MAX31865::MAX31865(SPI &_spi, PinName _ncs)
+    : spi(_spi), ncs(_ncs, 1), sensorPresent(false)
+{
+}
+
+bool MAX31865::begin(max31865_numwires_t wires)
+{
+    setWires(wires);
+    enableBias(true);
+    autoConvert(true);
+    clearFault();
+
+    return true;
+}
+
+uint8_t MAX31865::readFault(void)
+{
+    return readRegister8(MAX31865_FAULTSTAT_REG);
+}
+
+void MAX31865::clearFault(void)
+{
+    volatile uint8_t t = readRegister8(MAX31865_CONFIG_REG);
+    t &= ~0x2C;
+    t |= MAX31865_CONFIG_FAULTSTAT;
+    writeRegister8(MAX31865_CONFIG_REG, t);
+}
+
+void MAX31865::enableBias(bool b)
+{
+    volatile uint8_t t = readRegister8(MAX31865_CONFIG_REG);
+    if (b)
+    {
+        t |= MAX31865_CONFIG_BIAS; // enable bias
+    }
+    else
+    {
+        t &= ~MAX31865_CONFIG_BIAS; // disable bias
+    }
+    writeRegister8(MAX31865_CONFIG_REG, t);
+}
+
+void MAX31865::autoConvert(bool b)
+{
+    uint8_t t = readRegister8(MAX31865_CONFIG_REG);
+    if (b)
+    {
+        t |= MAX31865_CONFIG_MODEAUTO; // enable autoconvert
+    }
+    else
+    {
+        t &= ~MAX31865_CONFIG_MODEAUTO; // disable autoconvert
+    }
+    writeRegister8(MAX31865_CONFIG_REG, t);
+}
+
+void MAX31865::setWires(max31865_numwires_t wires)
+{
+    uint8_t t = readRegister8(MAX31865_CONFIG_REG);
+    if (wires == MAX31865_3WIRE)
+    {
+        t |= MAX31865_CONFIG_3WIRE;
+    }
+    else
+    {
+        // 2 or 4 wire
+        t &= ~MAX31865_CONFIG_3WIRE;
+    }
+    writeRegister8(MAX31865_CONFIG_REG, t);
+}
+
+float MAX31865::temperature(float RTDnominal, float refResistor, uint16_t rtdVal)
+{
+    // http://www.analog.com/media/en/technical-documentation/application-notes/AN709_0.pdf
+
+    float Z1, Z2, Z3, Z4, Rt, temp;
+
+    if (rtdVal == 0)
+    {
+        Rt = readRTD();
+
+        if (!sensorPresent)
+        {
+            return 0.0f;
+        }
+    }
+    else
+    {
+        Rt = rtdVal;
+    }
+    Rt /= 32768;
+    Rt *= refResistor;
+
+    Z1 = -RTD_A;
+    Z2 = RTD_A * RTD_A - (4 * RTD_B);
+    Z3 = (4 * RTD_B) / RTDnominal;
+    Z4 = 2 * RTD_B;
+
+    temp = Z2 + (Z3 * Rt);
+    temp = (sqrt(temp) + Z1) / Z4;
+
+    if (temp >= 0)
+        return temp;
+
+    // ugh.
+    float rpoly = Rt;
+
+    temp = -242.02f;
+    temp += 2.2228f * rpoly;
+    rpoly *= Rt; // square
+    temp += (float)2.5859e-3 * rpoly;
+    rpoly *= Rt; // ^3
+    temp -= (float)4.8260e-6 * rpoly;
+    rpoly *= Rt; // ^4
+    temp -= (float)2.8183e-8 * rpoly;
+    rpoly *= Rt; // ^5
+    temp += (float)1.5243e-10 * rpoly;
+
+    return temp;
+}
+
+uint16_t MAX31865::readRTD(void)
+{
+    uint16_t rtd = readRegister16(MAX31865_RTDMSB_REG);
+    sensorPresent = readFault() == 0;
+    clearFault();
+
+    rtd >>= 1;
+
+    return rtd;
+}
+
+/**********************************************/
+
+uint8_t MAX31865::readRegister8(uint8_t addr)
+{
+    uint8_t ret[] = {0};
+    readRegisterN(addr, ret, 1);
+    return ret[0];
+}
+
+uint16_t MAX31865::readRegister16(uint8_t addr)
+{
+    uint8_t buffer[2] = {0, 0};
+    readRegisterN(addr, buffer, 2);
+
+    uint16_t ret = buffer[0];
+    ret <<= 8;
+    ret |= buffer[1];
+
+    return ret;
+}
+
+void MAX31865::writeRegister8(uint8_t addr, uint8_t data)
+{
+    ncs = 0;                //select chip
+    spi.write(addr | 0x80); // make sure top bit is set
+    spi.write(data);
+    ncs = 1;
+}
+
+void MAX31865::readRegisterN(uint8_t address, uint8_t buffer[], uint8_t n)
+{
+    address &= 0x7F; // make sure top bit is not set
+
+    ncs = 0;
+
+    spi.write(address);
+
+    for (uint8_t i = 0; i < n; i++)
+    {
+        buffer[i] = spi.write(0x00);
+    }
+
+    ncs = 1;
+}
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MAX31865.h	Fri Mar 29 14:09:06 2019 +0000
@@ -0,0 +1,90 @@
+/*************************************************** 
+  This is a library for the Adafruit PT100/P1000 RTD Sensor w/MAX31865
+
+  Designed specifically to work with the Adafruit RTD Sensor
+  ----> https://www.adafruit.com/products/3328
+
+  This sensor uses SPI to communicate, 4 pins are required to  
+  interface
+  Adafruit invests time and resources providing this open source code, 
+  please support Adafruit and open-source hardware by purchasing 
+  products from Adafruit!
+
+  Written by Limor Fried/Ladyada for Adafruit Industries.  
+  BSD license, all text above must be included in any redistribution
+  
+  Modified for mbed project - Dan Julio - 5/2017
+  Improvements - freakone 3/2019
+ ****************************************************/
+#ifndef MAX31865_H
+#define MAX31865_H
+
+#include <stdint.h>
+#include "mbed.h"
+
+#define MAX31865_CONFIG_REG 0x00
+#define MAX31865_CONFIG_BIAS 0x80
+#define MAX31865_CONFIG_MODEAUTO 0x40
+#define MAX31865_CONFIG_MODEOFF 0x00
+#define MAX31865_CONFIG_1SHOT 0x20
+#define MAX31865_CONFIG_3WIRE 0x10
+#define MAX31865_CONFIG_24WIRE 0x00
+#define MAX31865_CONFIG_FAULTSTAT 0x02
+#define MAX31865_CONFIG_FILT50HZ 0x01
+#define MAX31865_CONFIG_FILT60HZ 0x00
+
+#define MAX31865_RTDMSB_REG 0x01
+#define MAX31865_RTDLSB_REG 0x02
+#define MAX31865_HFAULTMSB_REG 0x03
+#define MAX31865_HFAULTLSB_REG 0x04
+#define MAX31865_LFAULTMSB_REG 0x05
+#define MAX31865_LFAULTLSB_REG 0x06
+#define MAX31865_FAULTSTAT_REG 0x07
+
+#define MAX31865_FAULT_HIGHTHRESH 0x80
+#define MAX31865_FAULT_LOWTHRESH 0x40
+#define MAX31865_FAULT_REFINLOW 0x20
+#define MAX31865_FAULT_REFINHIGH 0x10
+#define MAX31865_FAULT_RTDINLOW 0x08
+#define MAX31865_FAULT_OVUV 0x04
+
+#define RTD_A 3.9083e-3
+#define RTD_B -5.775e-7
+
+typedef enum max31865_numwires
+{
+  MAX31865_2WIRE = 0,
+  MAX31865_3WIRE = 1,
+  MAX31865_4WIRE = 0
+} max31865_numwires_t;
+
+class MAX31865
+{
+public:
+  MAX31865(SPI &_spi, PinName _ncs);
+
+  bool begin(max31865_numwires_t x = MAX31865_2WIRE);
+
+  uint8_t isSensorPresent() { return sensorPresent; };
+  uint8_t readFault(void);
+  void clearFault(void);
+  uint16_t readRTD();
+
+  void setWires(max31865_numwires_t wires);
+  void autoConvert(bool b);
+  void enableBias(bool b);
+  float temperature(float RTDnominal, float refResistor, uint16_t rtdVal = 0);
+
+private:
+  SPI &spi;
+  DigitalOut ncs;
+  bool sensorPresent;
+
+  void readRegisterN(uint8_t addr, uint8_t buffer[], uint8_t n);
+  uint8_t readRegister8(uint8_t addr);
+  uint16_t readRegister16(uint8_t addr);
+  void writeRegister8(uint8_t addr, uint8_t reg);
+};
+
+#endif
+

--- a/max31865.cpp	Fri Mar 22 10:47:38 2019 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,179 +0,0 @@
-#include "max31865.h"
-#include "mbed.h"
-
-max31865::max31865(PinName MOSI, PinName MISO, PinName SCLK, PinName CS) : spi(MOSI, MISO, SCLK), cs(CS) // mosi, miso, sclk
-{
-    //constructor
-    cs = 1;                //deselect chip
-    spi.format(8, 1);      //set mode 1 and 8 bit
-    spi.frequency(500000); //set frequency to 0.5mhz
-    RTDpresent = false;
-    RTDtype = PT100;
-}
-
-float max31865::ReadRTD(void)
-{
-    volatile uint16_t reg_rtd = ReadRegistor16(MAX31856_RTDMSB_REG);
-    RTDpresent = ReadRegistor8(MAX31856_FAULTSTAT_REG) == 0;
-    ClearFault();
-
-    reg_rtd >>= 1;
-
-    float Z1, Z2, Z3, Z4, Rt, temp;
-
-    float RTDnominal = 100, refResistor = 400;
-
-    if (RTDtype == PT1000)
-    {
-        RTDnominal = 1000;
-        refResistor = 4000;
-    }
-
-    Rt = reg_rtd;
-    Rt /= 32768;
-    Rt *= refResistor;
-
-    Z1 = -RTD_A;
-    Z2 = RTD_A * RTD_A - (4 * RTD_B);
-    Z3 = (4 * RTD_B) / RTDnominal;
-    Z4 = 2 * RTD_B;
-
-    temp = Z2 + (Z3 * Rt);
-    temp = (sqrt(temp) + Z1) / Z4;
-
-    if (temp >= 0)
-        return temp;
-
-    float rpoly = Rt;
-
-    temp = -242.02;
-    temp += 2.2228 * rpoly;
-    rpoly *= Rt; // square
-    temp += 2.5859e-3 * rpoly;
-    rpoly *= Rt; // ^3
-    temp -= 4.8260e-6 * rpoly;
-    rpoly *= Rt; // ^4
-    temp -= 2.8183e-8 * rpoly;
-    rpoly *= Rt; // ^5
-    temp += 1.5243e-10 * rpoly;
-
-    return temp;
-}
-
-void max31865::Begin(max31865_numwires_t wires, max31865_rtd_t type)
-{
-    cs = 1;
-    RTDtype = type;
-    SetWires(wires);
-    EnableBias(true);
-    AutoConvert(true);
-    ClearFault();
-}
-
-int max31865::ReadFault()
-{
-    return ReadRegistor8(MAX31856_FAULTSTAT_REG);
-}
-
-void max31865::ClearFault()
-{
-    int t = ReadRegistor8(MAX31856_CONFIG_REG);
-    // t &= ~0x2C;
-    t |= MAX31856_CONFIG_FAULTSTAT;
-    WriteRegistor(MAX31856_CONFIG_REG, t);
-}
-
-void max31865::EnableBias(bool b)
-{
-    int t = ReadRegistor8(MAX31856_CONFIG_REG);
-    if (b)
-    {
-        t |= MAX31856_CONFIG_BIAS; // enable bias
-    }
-    else
-    {
-        t &= ~MAX31856_CONFIG_BIAS; // disable bias
-    }
-    WriteRegistor(MAX31856_CONFIG_REG, t);
-}
-
-void max31865::AutoConvert(bool b)
-{
-    int t = ReadRegistor8(MAX31856_CONFIG_REG);
-    if (b)
-    {
-        t |= MAX31856_CONFIG_MODEAUTO; // enable autoconvert
-    }
-    else
-    {
-        t &= ~MAX31856_CONFIG_MODEAUTO; // disable autoconvert
-    }
-    WriteRegistor(MAX31856_CONFIG_REG, t);
-}
-
-void max31865::SetWires(max31865_numwires_t wires)
-{
-    int t = ReadRegistor8(MAX31856_CONFIG_REG);
-
-    if (wires == MAX31865_3WIRE)
-    {
-        t |= MAX31856_CONFIG_3WIRE;
-    }
-    else
-    {
-        // 2 or 4 wire
-        t &= ~MAX31856_CONFIG_3WIRE;
-    }
-    WriteRegistor(MAX31856_CONFIG_REG, t);
-}
-
-int max31865::ReadRegistor8(int address)
-{
-    int ret = 0;
-    ReadRegistorN(address, &ret, 1);
-    return ret;
-}
-
-int max31865::ReadRegistor16(int address)
-{
-    int buffer[2] = {0, 0};
-    ReadRegistorN(address, buffer, 2);
-
-    int ret = buffer[0];
-    ret <<= 8;
-    ret |= buffer[1];
-
-    return ret;
-}
-
-void max31865::ReadRegistorN(int address, int buffer[], int n)
-{
-    address &= 0x7F; // make sure top bit is not set
-
-    cs = 0;
-
-    spiXfer(address);
-
-    while (n--)
-    {
-        buffer[0] = spiXfer(0xFF);
-        buffer++;
-    }
-
-    cs = 1;
-}
-
-void max31865::WriteRegistor(int address, int data)
-{
-
-    cs = 0;                  //select chip
-    spiXfer(address | 0x80); // make sure top bit is set
-    spiXfer(data);
-
-    cs = 1;
-}
-
-int max31865::spiXfer(int x)
-{
-    return spi.write(x);
-}
\ No newline at end of file

--- a/max31865.h	Fri Mar 22 10:47:38 2019 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,80 +0,0 @@
-#ifndef MBED_MAX31865_H
-#define MBED_MAX31865_H
-
-#include "mbed.h"
-
-#define MAX31856_CONFIG_REG 0x00
-#define MAX31856_CONFIG_BIAS 0x80
-#define MAX31856_CONFIG_MODEAUTO 0x40
-#define MAX31856_CONFIG_MODEOFF 0x00
-#define MAX31856_CONFIG_1SHOT 0x20
-#define MAX31856_CONFIG_3WIRE 0x10
-#define MAX31856_CONFIG_24WIRE 0x00
-#define MAX31856_CONFIG_FAULTSTAT 0x02
-#define MAX31856_CONFIG_FILT50HZ 0x01
-#define MAX31856_CONFIG_FILT60HZ 0x00
-
-#define MAX31856_RTDMSB_REG 0x01
-#define MAX31856_RTDLSB_REG 0x02
-#define MAX31856_HFAULTMSB_REG 0x03
-#define MAX31856_HFAULTLSB_REG 0x04
-#define MAX31856_LFAULTMSB_REG 0x05
-#define MAX31856_LFAULTLSB_REG 0x06
-#define MAX31856_FAULTSTAT_REG 0x07
-
-#define MAX31865_FAULT_HIGHTHRESH 0x80
-#define MAX31865_FAULT_LOWTHRESH 0x40
-#define MAX31865_FAULT_REFINLOW 0x20
-#define MAX31865_FAULT_REFINHIGH 0x10
-#define MAX31865_FAULT_RTDINLOW 0x08
-#define MAX31865_FAULT_OVUV 0x04
-
-#define RTD_A 3.9083e-3
-#define RTD_B -5.775e-7
-
-typedef enum max31865_numwires
-{
-  MAX31865_2WIRE = 0,
-  MAX31865_3WIRE = 1,
-  MAX31865_4WIRE = 0
-} max31865_numwires_t;
-
-typedef enum
-{
-  PT100 = 0,
-  PT1000 = 0
-
-} max31865_rtd_t;
-
-class max31865
-{
-public:
-  max31865(PinName MOSI, PinName MISO, PinName SCLK, PinName CS);
-
-  void Begin(max31865_numwires_t wires, max31865_rtd_t type);
-  int ReadFault();
-  void ClearFault();
-  float ReadRTD();
-  bool IsRTDPresent() { return RTDpresent; };
-
-  void SetWires(max31865_numwires_t wires);
-  void AutoConvert(bool b);
-  void EnableBias(bool b);
-
-private:
-  SPI spi;
-  DigitalOut cs;
-  bool RTDpresent;
-  max31865_rtd_t RTDtype;
-
-  void
-  ReadRegistorN(int address, int buffer[], int n);
-
-  int ReadRegistor8(int address);
-  int ReadRegistor16(int address);
-
-  void WriteRegistor(int address, int reg);
-  int spiXfer(int address);
-};
-
-#endif
\ No newline at end of file