Revision 3:f39791139435, committed 2019-01-28

Comitter:

phonemacro

Date:

Mon Jan 28 00:39:50 2019 +0000

Parent:

2:7a20e65da621

Child:

4:ac75d4d62471

Commit message:

Use 1.8V for VDD. Updated the interface for reading registers.

Changed in this revision

--- a/max31723.cpp	Sun Jan 27 07:26:37 2019 +0000
+++ b/max31723.cpp	Mon Jan 28 00:39:50 2019 +0000
@@ -31,6 +31,14 @@
 *******************************************************************************
 */
 #include "max31723.h"
+
+union max31723_raw_data {
+    struct {
+        uint8_t lsb;
+        uint8_t msb;
+    };
+    uint16_t wrd;
+};
  
 MAX31723::MAX31723(SPI &spi, DigitalOut &ce_pin) : m_spi(spi), m_chip_enable(ce_pin)
 {
@@ -55,11 +63,11 @@
     return MAX31723_NO_ERROR;
 }
 
-int MAX31723::perform_one_shot_int(uint8_t resolution)
+int MAX31723::perform_one_shot(uint8_t resolution, uint8_t interrupt_mode)
 {
     if (resolution <= MAX31723_CFG_RESOLUTION_12BIT) {
         write_reg(0, MAX31723_REG_CFG | MAX31723_WRITE_MASK);
-        write_reg(MAX31723_CFG_TM_MODE_INTERRUPT | MAX31723_CFG_1SHOT |
+        write_reg(interrupt_mode | MAX31723_CFG_1SHOT |
             resolution | MAX31723_CFG_STANDBY,
             MAX31723_REG_CFG | MAX31723_WRITE_MASK);
     } else
@@ -67,20 +75,43 @@
     return MAX31723_NO_ERROR;
 }
 
-float MAX31723::read_temp()
+int MAX31723::perform_one_shot_int(uint8_t resolution)
 {
-    uint8_t lsb, msb;
-    uint16_t raw_temp;
-    float temperature;
-    wait(0.2);
-    read_reg(lsb, MAX31723_REG_TEMP_LSB);
-    read_reg(msb, MAX31723_REG_TEMP_MSB);
-    raw_temp =  int16_t((msb << 8) | (lsb));
-    raw_temp =  raw_temp >> 4;
-    temperature = raw_temp * 0.0625 ;
-    return temperature;
+    int ret;
+    ret = perform_one_shot(resolution, MAX31723_CFG_TM_MODE_INTERRUPT);
+    return ret;
+}
+
+int MAX31723::perform_one_shot_comparator(uint8_t resolution)
+{
+    int ret;
+    ret = perform_one_shot(resolution, 0);
+    return ret;
 }
 
+uint8_t MAX31723::read_cfg()
+{
+    uint8_t cfg;
+    read_reg(cfg, MAX31723_REG_CFG);
+    return cfg;
+}
+
+float MAX31723::read_reg_as_temperature(uint8_t reg)
+{
+    max31723_raw_data raw;
+    float temperature;
+    if (reg >= MAX31723_REG_TEMP_LSB && reg <= MAX31723_REG_MAX) {
+        read_reg(raw.lsb, reg);
+        read_reg(raw.msb, reg+1);
+        raw.wrd =  raw.wrd >> MAX31723_UNUSED_BITS;
+        temperature = raw.wrd * MAX31723_CF_LSB;
+        return temperature;
+    } else {
+        printf("Input read_registers_as_temperature is invalid, %d r\n",
+            reg);
+        return 0;
+    }
+}
 
 float MAX31723::celsius_to_fahrenheit(float temp_c)
 {

--- a/max31723.h	Sun Jan 27 07:26:37 2019 +0000
+++ b/max31723.h	Mon Jan 28 00:39:50 2019 +0000
@@ -45,6 +45,11 @@
 #define MAX31723_REG_CFG                0x00
 #define MAX31723_REG_TEMP_LSB           0x01
 #define MAX31723_REG_TEMP_MSB           0x02
+#define MAX31723_REG_TRIP_HI_LSB        0x03
+#define MAX31723_REG_TRIP_HI_MSB        0x04
+#define MAX31723_REG_TRIP_LO_LSB        0x05
+#define MAX31723_REG_TRIP_LO_MSB        0x06
+#define MAX31723_REG_MAX                MAX31723_REG_TRIP_LO_MSB
 
 /* Configuration, Status masks */
 #define MAX31723_CFG_CONTINUOUS         0x00
@@ -60,15 +65,20 @@
 #define MAX31723_CFG_NVB_NVRAM_BUSY     0x20
 #define MAX31723_CFG_MEMW_CFG_WR_EEPROM 0x40
 
-#define MAX31723_CONV_TIME_MSEC_9BIT    .025
-#define MAX31723_CONV_TIME_MSEC_10BIT   .050
-#define MAX31723_CONV_TIME_MSEC_11BIT   .100
-#define MAX31723_CONV_TIME_MSEC_12BIT   .200
+#define MAX31723_CONV_TIME_MSEC_9BIT    0.025
+#define MAX31723_CONV_TIME_MSEC_10BIT   0.050
+#define MAX31723_CONV_TIME_MSEC_11BIT   0.100
+#define MAX31723_CONV_TIME_MSEC_12BIT   0.200
+
+#define MAX31723_NVRAM_WRITE_TIME_MSEC  0.015
+
+#define MAX31723_CF_LSB                 0.0625f
+#define MAX31723_UNUSED_BITS            4
 
 /**
 * @brief 9-bit to 12bit device temperature sensor with digital-to-analog converters (DACs)
 *        for the MAX31723, MAX5214.
-* @version 1.0000.0001
+* @version 1.0000.0002
 *
 * @details The MAX31722/MAX31723 provides device temperature readings
 * for thermostats and thermometers. Communications may be either SPI or
@@ -109,20 +119,11 @@
     int write_reg(uint8_t val, uint8_t reg);
 
     /** 
-     * @brief Read a value from a register
-     * @param val - 8-bit value read from the register
-     * @param reg - register address
-     * @return 0 on success, negative number on failure
-     */
-    int read_reg(uint8_t &val, uint8_t reg);
-
-    /** 
-     * @brief Write a value to a register
-     * @param val - 8-bit value to write to the register
-     * @param reg - register address
+     * @brief Reads the temperature registers
+     * @param reg - the low byte address of the temperature register
      * @return temprature in degrees celsius
      */
-    float read_temp();
+    float read_reg_as_temperature(uint8_t reg);
 
     /** 
      * @brief Configures the device to perform a one-shot temperature reading
@@ -133,12 +134,26 @@
     int perform_one_shot_int(uint8_t resolution);
 
     /** 
+     * @brief Configures the device to perform a one-shot temperature reading
+     *        and places the device in standby mode, comparator mode.
+     * @param resolution - the resolution of the calculation is set to this
+     * @return 0 on success, negative number on failure
+     */
+    int perform_one_shot_comparator(uint8_t resolution);
+
+    /** 
      * @brief Converts Celcius degrees to Fahrenheit
      * @param temp_c - the temperature in Celsius degrees
      * @return 0 on success, negative number on failure
      */
     float celsius_to_fahrenheit(float temp_c);
 
+    /** 
+     * @brief Reads the configuration register
+     * @return value of the configuration register
+     */
+    uint8_t read_cfg();
+
 
     /************************************************************
      * @brief Default destructor for MAX31723 Class.  
@@ -153,10 +168,28 @@
      *************************************************************
      */
     ~MAX31723();
+    protected:
+    /** 
+     * @brief Configures the device to perform a one-shot temperature reading
+     *        and places the device in standby mode, interrupt mode.
+     * @param resolution - the resolution of the calculation is set to this
+     * @return 0 on success, negative number on failure
+     */
+    int perform_one_shot(uint8_t resolution, uint8_t interrupt_mode);
+
+
     private:
-    // SPI object
+    /** 
+     * @brief Read a value from a register
+     * @param val - 8-bit value read from the register
+     * @param reg - register address
+     * @return 0 on success, negative number on failure
+     */
+    int read_reg(uint8_t &val, uint8_t reg);
+
+    /* SPI object */
     SPI &m_spi;
-    // chip enable pin
+    /* chip enable pin */
     DigitalOut &m_chip_enable;
 };