Diff: CMLX90620.h

Revision:

53:72f350a6d09c

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/CMLX90620.h	Thu Apr 14 13:45:38 2016 +0100
@@ -0,0 +1,215 @@
+/*
+ * CMLX90620.h
+ *
+ *  Created on: 12 Mar 2016
+ *      Author: mike
+ */
+
+#ifndef MLX90620_H
+#define MLX90620_H
+
+#include "mbed.h"
+
+/** Software routines to access the Melexis MLX90620 64 pixel (4 X 16) infrared sensor array
+ *   The MLX90620's internal RAM has different i2c behavior than it's internal EEPROM
+ *   As a result, the MLX90620's RAM uses more primitive mbed i2c commands than does the EEPROM.
+ *
+ * @code
+ * #include "mbed.h"
+ * #include "MLX90620.h"
+ *
+ * char* EEbuf = new char[256];     //buffer for contents of EEPROM
+ * char* RamCmmd = new char[8];     //holds / sends MLX90620 RAM commands
+ * char* RamBuf = new char[128];    //0x3f words, values are 'unsigned short'
+ *
+ * Serial pc(USBTX, USBRX);
+ * MLX90620 mlx(p9, p10, "mlx");
+ * //MLX90620 mlx(PTE0, PTE1, "mlx");
+ *
+ * float Ta = 0.0;
+ * float TempPxl = 0.0;
+ *
+ *
+ * int main() {
+ *     pc.baud(115200);
+ *     mlx.LoadEEPROM();         //if returns non 0, MLX90620 may not be unconnected to i2c bus
+ *     mlx.SetOscTrimReg();      //if returns non 0, MLX90620 is having RAM access problems with i2c bus
+ *     mlx.SetConfigReg();       //if returns non 0, WTF?? - shouldn't be any i2c problems at this point
+ *     mlx.StartMeasurement();   //if returns non 0, WTF??
+ *     wait(0.5);
+ *     mlx.CalcTa_To();          //if returns non 0, WTF??
+ *     Ta = mlx.GetDieTemp();
+ *     pc.printf("\nTa = %f\n\n", Ta);
+ *     //simplistic dump of pixel array. Any terminal character
+ *     //generates another acquisition cycle.
+ *     //allows the program to run at maximum refresh rate of 4Hz
+ *     //In order to save time, mlx.StartMeasurement(); is done
+ *     //just after mlx.GetMLXRam();. This way the CPU can process
+ *     //lots of floating math while the MLX90620 gets another round.
+ *     while(1) {
+ *         int config = mlx.GetConfigReg();
+ *         int chk = config & 0x0300;
+ *         if(chk == 0) {
+ *             pc.printf("\nIR Array Capture\n");
+ *             mlx.LoadMLXRam();         //if returns 0, WTF??
+ *             mlx.StartMeasurement();   //if returns 0, WTF??
+ *             for(int i = 0; i < 64; i++) {
+ *                 TempPxl = mlx.CalcPixel(i);
+ *                 pc.printf("Pix %2d   Temp %.3f\n", i, TempPxl);
+ *             }
+ *         } else {
+ *             wait_ms(100);
+ *         }
+ *     }
+ *}
+ * @endcode
+ */
+/* MLX90620 controller class
+ */
+class MLX90620 {
+
+public:
+
+    /** Create a MLX90620 object using the specified I2C object
+     *
+     * @param constructor, - the I2C object to communicate with
+     */
+    MLX90620(PinName sda, PinName scl, const char* name);
+
+
+    /** Copy the contents of the MLX90620 EEPROM into local buffer for later use
+     *    Returns '1' if i2c error, '0' if ok.
+     *  Only done at initialization.  MUST be the first thing you do in MAIN.
+     *
+     * @param NONE, - loads all 256 bytes from EEPROM into local buffer
+     */
+    int LoadEEPROM();
+
+
+    /** Initialize the MLX90620's Oscillator Trim Register
+     *    Data is derived from values received from the EEPROM
+     *    Returns '1' if i2c error, '0' if ok.
+     *  Register is only set once during initialization
+     *
+     * @param NONE, - 7 lsb bits from 16 bit value, set by EEPROM value at initialization
+     */
+    int SetOscTrimReg();
+
+
+    /** Get the MLX90620's Oscillator Trim Register
+     *    Returns the Oscillator Trim Register value
+     *
+     * @param NONE, - 7 lsb bits from 16 bit value, Read from MLX RAM
+     */
+    unsigned short GetOscTrimReg();
+
+
+    /** Set the MLX90620's Configuration Register
+     *    Returns '0' if i2c error, '1' if ok.
+     *  Register is set only during initialization. Inital setup:
+     *  1. ADC low reference
+     *  2. Ta Ref Rate 8Hz
+     *  3. I2C FM+ mode enabled
+     *  4. MD / Brownout bit set
+     *  5. Normal Operation (non-Sleep) mode
+     *  6. Step(Melexis reserved) mode. (removed from later datasheets, but used in this code)
+     *  7. IR refresh rate 4Hz
+     *
+     * @param NONE, - 16 bit value set by code at initialization
+     */
+    int SetConfigReg();
+
+
+    /** Get the MLX90620's Configuration Register
+     *    Returns the Configuration Register value
+     *  periodic check for Ta ready, IR Array ready and brownout conditions
+     *
+     * @param returns unsigned short, - 16 bit value, Read from MLX RAM
+     */
+    unsigned short GetConfigReg();
+
+
+    /** Get the MLX90620's PTAT register. Register read at every Ta cycle
+     *    Returns the Proportional To Ambient Temperature Register value
+     *
+     * @param returns unsigned short, - 16 bit value, PTAT sensor, Read from MLX RAM
+     */
+    unsigned short GetPTATReg();
+
+
+    /** Get the MLX90620's TGC register
+     *    Returns the Temperature Gradient Coefficient Register value
+     *
+     * @param returns short, - 16 bit value, TGC, Read from MLX RAM
+     */
+    short GetTGCReg();
+
+
+    /** Get the MLX90620's IR pixel array and dump into local buffer
+     *    Returns nothing
+     *
+     * @param NONE, - loads IR Pixel array into buffer (0x7F bytes, 0x3f Pixels), Read from MLX RAM
+     */
+    void LoadMLXRam();
+
+
+    /** Start a Ta and IR array conversion update cycle
+     *    Returns '1' if i2c error, '0' if ok.
+     *  Also calls GetPTATReg() and GetTGCReg()
+     *
+     * @param NONE, - MLX90620 starts aquiring data, takes about 250mS /w 4Hz refresh rate
+     */
+    int StartMeasurement();
+
+
+    /** Get the MLX90620's die temperature in degC
+     *    Returns MLX90620 die temperature
+     *  Needs to be performed before every array update calculation
+     *
+     * @param returns, - float of die temperature of MLX90620 in degC
+     */
+    float GetDieTemp();
+
+
+    /** Calculate initial MLX90620 offsets. Performed only at initialization
+     *    Returns nothing
+     *
+     * @param NONE, - sets the MLX90620 with die correcting factors at initialization
+     */
+    void CalcTa_To();
+
+
+    /** Calculate temperature of any pixel within the array (0 - 63)
+     *  after an IR array dump into local buffer,
+     *
+     * @param set int(0-63) of pixel to convert, returns double of temperature in degC of pixel
+     */
+    double CalcPixel(int Pixel);
+
+private:
+    I2C _i2c;                   //local i2c communication interface instance
+    unsigned short Config;
+    unsigned short OscTrim;
+    unsigned short PtatD;
+    short VCP;
+    short Vth25X;
+    signed char AcpX;
+    signed char BcpX;
+    float Kt1fX;
+    float Kt2fX;
+    float TaXX;
+    signed char TGCX;
+    char BiScaleX;
+    unsigned short theta0X;
+    char theta0ScaleX;
+    char deltaThetaScaleX;
+    unsigned short elipsonX;
+    signed char AiPixelX;
+    signed char BiPixelX;
+    char dThetaPixelX;
+    short VirPixelX;
+    double TempPxlX;
+
+};
+
+#endif