Revision 0:eee9c8ba72ff, committed 2014-08-28

Comitter:

melse

Date:

Thu Aug 28 10:32:20 2014 +0000

Commit message:

Initial Commit

Changed in this revision

diff -r 000000000000 -r eee9c8ba72ff INA219.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/INA219.cpp	Thu Aug 28 10:32:20 2014 +0000
@@ -0,0 +1,88 @@
+#include "INA219.hpp"
+
+INA219::INA219 (PinName sda, PinName scl, int addr, int freq, resolution_t res) : I2C(sda, scl), resolution(res), i2c_addr(addr << 1)
+{
+    I2C::frequency(freq);
+    
+    // by default, calibrate to this level.
+    calibrate_16v_400mA();
+}
+
+// Private Methods
+
+void INA219::write_register (uint8_t reg, uint8_t* data, int length)
+{
+    char* transmission = (char*)malloc(length + 1);
+    memcpy(transmission + 1, data, length);
+
+    transmission[0] = reg;
+    I2C::write(i2c_addr, transmission, length + 1);
+
+    free(transmission);
+}
+
+void INA219::write_register_u16 (uint8_t reg, uint16_t data)
+{
+    char transmission[3];
+    transmission[0] = reg;
+    transmission[1] = (data >> 8) & 0xff;
+    transmission[2] = data & 0xff;
+
+    I2C::write(i2c_addr, transmission, 3);
+}
+
+void INA219::write_null(uint8_t reg) {
+    I2C::write(i2c_addr, (char*)&reg, 1);    
+}
+
+uint16_t INA219::read_register_u16 (uint8_t reg)
+{
+    write_null(reg);
+
+    char data[2];
+    I2C::read(i2c_addr, data, 2);
+
+    uint16_t ret_val = data[0] << 8 | data[1];
+    return ret_val;
+}
+
+// Public Methods
+
+void INA219::calibrate_16v_400mA()
+{
+    // ASSUMING A 0.1 OHM RESISTOR!
+    write_register_u16(INA219_REG_CALIBRATION, 8192);
+
+    // Write to config register
+
+    uint16_t resolution_mask = 0x0000;
+    
+    if (resolution == RES_12BITS)
+        resolution_mask = INA219_CONFIG_BADCRES_12BIT | INA219_CONFIG_SADCRES_12BIT_1S_532US;
+    else if (resolution == RES_11BITS)
+        resolution_mask = INA219_CONFIG_BADCRES_11BIT | INA219_CONFIG_SADCRES_11BIT_1S_276US;
+    else if (resolution == RES_10BITS)
+        resolution_mask = INA219_CONFIG_BADCRES_10BIT | INA219_CONFIG_SADCRES_10BIT_1S_148US;
+    else // resolution == RES_9BITS
+        resolution_mask = INA219_CONFIG_BADCRES_9BIT | INA219_CONFIG_SADCRES_9BIT_1S_84US;
+
+    write_register_u16(INA219_REG_CONFIG, INA219_CONFIG_BVOLTAGERANGE_16V |
+                    INA219_CONFIG_GAIN_1_40MV |
+                    resolution_mask |
+                    INA219_CONFIG_MODE_SANDBVOLT_CONTINUOUS);
+                    
+    // Set current divider
+    current_divider = 20;
+    power_divider = 1;
+}
+
+int16_t INA219::read_current_raw()
+{
+    return (int16_t)read_register_u16(INA219_REG_CURRENT);
+}
+
+float INA219::read_current_mA()
+{
+    float raw_current = read_current_raw();
+    return raw_current / current_divider;
+}
\ No newline at end of file

diff -r 000000000000 -r eee9c8ba72ff INA219.hpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/INA219.hpp	Thu Aug 28 10:32:20 2014 +0000
@@ -0,0 +1,157 @@
+#include "mbed.h"
+#include "INA219_consts.h"
+
+#define DEBUG
+
+/// Represents the different supported voltage levels
+typedef enum {
+    BUS_16V=16,
+    BUS_32V=32
+} busvoltage_t;
+
+/** @enum Resolution typedef
+ *  @brief Represents the different ADC resolutions supported by the INA219.
+ */
+typedef enum {
+    RES_12BITS=12,  ///< 12 bit precision (532us)
+    RES_11BITS=11,  ///< 11 bit precision (276us)
+    RES_10BITS=10,  ///< 10 bit precision (148us)
+    RES_9BITS =9    ///< 9 bit precision (84us)
+} resolution_t;
+
+/** @class INA219
+ *  @brief A class to represent the INA219 breakout board from Adafruit.
+ */
+class INA219: protected I2C
+{
+public:
+    /** Creates an instance of the INA219 device.
+     *
+     *  @param sda An I2C data pin.
+     *  @param scl An I2C clock pin.
+     *  @param addr The I2C address of the INA219. (Default = 0x40)
+     *  @param freq The I2C clock frequency.
+     *  @param res The desired resolution of the INA219's ADC.
+     */
+    INA219 (PinName sda, PinName scl, int addr=0x40, int freq=100000, resolution_t res=RES_12BITS);
+
+    /** Reads the current raw value of current from the INA219.
+     *
+     *  @see read_current_mA
+     *
+     *  @returns
+     *      A value between -32768 and +32768. Depending on the current calibration and configuration register values, the corresponding current can be calculated.
+     */
+    int16_t read_current_raw();
+    /** Reads the current from the INA219 and calculates the actual value in mA.
+     *
+     *  @see read_current_raw
+     *
+     *  @returns
+     *      A floating point value corresponding to the current flowing through the current shunt, in mA.
+     */
+    float read_current_mA();
+
+    /** Reads the raw power value from the INA219.
+     *
+     *  @see read_power_mW
+     *
+     *  @returns
+     *      A value between -32768 and +32768. Depending on the calibration and configuration register values, the actual power can be calculated.
+     */
+    //int16_t read_power_raw();
+    /** Reads the power from the INA219 and calculates the actual value in mW.
+     *
+     *  @see read_power_raw
+     *
+     *  @returns
+     *      A floating point value corresponding to the power being used in the circuit, in mW.
+     */
+    //float read_power_mW();
+
+    /** Reads the raw shunt voltage value from the INA219.
+     *
+     *  @see read_shunt_voltage_mV
+     *
+     *  @returns
+     *      A value between -32768 and +32768. Depending on the calibration and configuration register values, the actual shunt voltage can be calculated.
+     */
+    //int16_t read_shunt_voltage_raw();
+    /** Reads the shunt voltage from the INA219 and calculates the actual value in mV.
+     *
+     *  @see read_shunt_voltage_raw
+     *
+     *  @returns
+     *      A floating point value corresponding to the potential difference across the current shunt, in mV.
+     */
+    //float read_shunt_voltage_mV();
+
+    /** Reads the raw bus voltage.
+     *
+     *  @see read_bus_voltage
+     *
+     *  @returns
+     *      A value between -32768 and +32768 corresponding to the bus voltage.
+     */
+    //int16_t read_bus_voltage_raw();
+    /** Reads the bus voltage and uses it to calculate the actual bus voltage.
+     *
+     *  @see read_bus_voltage_raw
+     *
+     *  @returns
+     *      A floating point value corresponding to the voltage of V+ (in V).
+     */
+    //float read_bus_voltage();
+
+    /** Sets the calibration register.
+     *     
+     *  Specifies a maximum bus voltage of 16V and maximum current of 400mA.
+     *  
+     */
+    void calibrate_16v_400mA();
+
+protected:
+    resolution_t resolution;
+
+    int i2c_addr;
+    int current_divider;
+    int power_divider;
+    //...
+
+    /** Writes a uint8_t array to the specified I2C register.
+     *
+     *  @see write_register_u16
+     *
+     *  @param reg (8-Bit) Register address to be written to.
+     *  @param data An array of bytes with the data to be written.
+     *  @param length The length of the array.
+     */
+    void write_register(uint8_t reg, uint8_t* data, int length);
+    /** Writes a uint16_t to the specified I2C register.
+     *
+     *  @see write_register
+     *
+     *  @param reg (8-Bit) Register address to be written to.
+     *  @param data (16-Bit) Data to be written.
+     */
+    void write_register_u16(uint8_t reg, uint16_t data);
+    /** Reads a value from the specified I2C register.
+     *
+     *  @see write_register
+     *  @see write_register_u16
+     *
+     *  @param reg (8-Bit) Register to be read from.
+     *
+     *  @returns
+     *      The contents of the specified register, as a 16 bit integer.
+     */
+    uint16_t read_register_u16(uint8_t reg);
+    
+    /** Writes nothing to a specified register. (Used to tell the chip that we want to read from that register)
+     *
+     *  @see read_register_u16
+     *
+     *  @param reg The register for nothing to be written to.
+     */
+     void write_null(uint8_t reg);
+};

diff -r 000000000000 -r eee9c8ba72ff INA219_consts.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/INA219_consts.h	Thu Aug 28 10:32:20 2014 +0000
@@ -0,0 +1,91 @@
+/*
+    'Borrowed' from Adafruit's INA219 libarary. Licensed under the BSD license.
+    
+    https://github.com/adafruit/Adafruit_INA219
+*/
+
+// Hopefully Adafruit won't mind if I borrow this...
+
+/*=========================================================================
+    I2C ADDRESS/BITS
+    -----------------------------------------------------------------------*/
+#define INA219_ADDRESS                         (0x40)    // 1000000 (A0+A1=GND)
+#define INA219_READ                            (0x01)
+/*=========================================================================*/
+
+/*=========================================================================
+    CONFIG REGISTER (R/W)
+    -----------------------------------------------------------------------*/
+#define INA219_REG_CONFIG                      (0x00)
+/*---------------------------------------------------------------------*/
+#define INA219_CONFIG_RESET                    (0x8000)  // Reset Bit
+
+#define INA219_CONFIG_BVOLTAGERANGE_MASK       (0x2000)  // Bus Voltage Range Mask
+#define INA219_CONFIG_BVOLTAGERANGE_16V        (0x0000)  // 0-16V Range
+#define INA219_CONFIG_BVOLTAGERANGE_32V        (0x2000)  // 0-32V Range
+
+#define INA219_CONFIG_GAIN_MASK                (0x1800)  // Gain Mask
+#define INA219_CONFIG_GAIN_1_40MV              (0x0000)  // Gain 1, 40mV Range
+#define INA219_CONFIG_GAIN_2_80MV              (0x0800)  // Gain 2, 80mV Range
+#define INA219_CONFIG_GAIN_4_160MV             (0x1000)  // Gain 4, 160mV Range
+#define INA219_CONFIG_GAIN_8_320MV             (0x1800)  // Gain 8, 320mV Range
+
+#define INA219_CONFIG_BADCRES_MASK             (0x0780)  // Bus ADC Resolution Mask
+#define INA219_CONFIG_BADCRES_9BIT             (0x0080)  // 9-bit bus res = 0..511
+#define INA219_CONFIG_BADCRES_10BIT            (0x0100)  // 10-bit bus res = 0..1023
+#define INA219_CONFIG_BADCRES_11BIT            (0x0200)  // 11-bit bus res = 0..2047
+#define INA219_CONFIG_BADCRES_12BIT            (0x0400)  // 12-bit bus res = 0..4097
+
+#define INA219_CONFIG_SADCRES_MASK             (0x0078)  // Shunt ADC Resolution and Averaging Mask
+#define INA219_CONFIG_SADCRES_9BIT_1S_84US     (0x0000)  // 1 x 9-bit shunt sample
+#define INA219_CONFIG_SADCRES_10BIT_1S_148US   (0x0008)  // 1 x 10-bit shunt sample
+#define INA219_CONFIG_SADCRES_11BIT_1S_276US   (0x0010)  // 1 x 11-bit shunt sample
+#define INA219_CONFIG_SADCRES_12BIT_1S_532US   (0x0018)  // 1 x 12-bit shunt sample
+#define INA219_CONFIG_SADCRES_12BIT_2S_1060US  (0x0048)  // 2 x 12-bit shunt samples averaged together
+#define INA219_CONFIG_SADCRES_12BIT_4S_2130US  (0x0050)  // 4 x 12-bit shunt samples averaged together
+#define INA219_CONFIG_SADCRES_12BIT_8S_4260US  (0x0058)  // 8 x 12-bit shunt samples averaged together
+#define INA219_CONFIG_SADCRES_12BIT_16S_8510US (0x0060)  // 16 x 12-bit shunt samples averaged together
+#define INA219_CONFIG_SADCRES_12BIT_32S_17MS   (0x0068)  // 32 x 12-bit shunt samples averaged together
+#define INA219_CONFIG_SADCRES_12BIT_64S_34MS   (0x0070)  // 64 x 12-bit shunt samples averaged together
+#define INA219_CONFIG_SADCRES_12BIT_128S_69MS  (0x0078)  // 128 x 12-bit shunt samples averaged together
+
+#define INA219_CONFIG_MODE_MASK                (0x0007)  // Operating Mode Mask
+#define INA219_CONFIG_MODE_POWERDOWN           (0x0000)
+#define INA219_CONFIG_MODE_SVOLT_TRIGGERED     (0x0001)
+#define INA219_CONFIG_MODE_BVOLT_TRIGGERED     (0x0002)
+#define INA219_CONFIG_MODE_SANDBVOLT_TRIGGERED (0x0003)
+#define INA219_CONFIG_MODE_ADCOFF              (0x0004)
+#define INA219_CONFIG_MODE_SVOLT_CONTINUOUS    (0x0005)
+#define INA219_CONFIG_MODE_BVOLT_CONTINUOUS    (0x0006)
+#define INA219_CONFIG_MODE_SANDBVOLT_CONTINUOUS (0x0007)
+/*=========================================================================*/
+
+/*=========================================================================
+    SHUNT VOLTAGE REGISTER (R)
+    -----------------------------------------------------------------------*/
+#define INA219_REG_SHUNTVOLTAGE                (0x01)
+/*=========================================================================*/
+
+/*=========================================================================
+    BUS VOLTAGE REGISTER (R)
+    -----------------------------------------------------------------------*/
+#define INA219_REG_BUSVOLTAGE                  (0x02)
+/*=========================================================================*/
+
+/*=========================================================================
+    POWER REGISTER (R)
+    -----------------------------------------------------------------------*/
+#define INA219_REG_POWER                       (0x03)
+/*=========================================================================*/
+
+/*=========================================================================
+    CURRENT REGISTER (R)
+    -----------------------------------------------------------------------*/
+#define INA219_REG_CURRENT                     (0x04)
+/*=========================================================================*/
+
+/*=========================================================================
+    CALIBRATION REGISTER (R/W)
+    -----------------------------------------------------------------------*/
+#define INA219_REG_CALIBRATION                 (0x05)
+/*=========================================================================*/
\ No newline at end of file