Revision 0:5a1830df0b66, committed 2019-10-08

Comitter:

PC2ROBOT

Date:

Tue Oct 08 14:59:11 2019 +0000

Commit message:

as5048

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/as5048spi.cpp	Tue Oct 08 14:59:11 2019 +0000
@@ -0,0 +1,132 @@
+#include "as5048spi.h"
+
+As5048Spi::As5048Spi(PinName mosi, PinName miso, PinName sclk, PinName chipselect, int ndevices) :
+    _nDevices(ndevices),
+    _chipSelectN(chipselect),
+    _spi(mosi, miso, sclk)
+{
+    _chipSelectN.write(1);
+    // AS5048 needs 16-bits for is commands
+    // Mode = 1: 
+    //  clock polarity = 0 --> clock pulse is high
+    //  clock phase = 1 --> sample on falling edge of clock pulse
+    _spi.format(16, 1);
+    
+    // Set clock frequency to 1 MHz (max is 10Mhz)
+    _spi.frequency(1000000);
+    
+    _readBuffer = new int[ndevices];
+}
+
+As5048Spi::~As5048Spi()
+{
+    delete [] _readBuffer;
+}
+
+int As5048Spi::degrees(int sensor_result)
+{
+    return mask(sensor_result) * 36000 / 0x4000;
+}
+
+
+int As5048Spi::radian(int sensor_result)
+{
+    return mask(sensor_result) * 62832 / 0x4000;
+}
+
+bool As5048Spi::error(int device)
+{
+    if( device == -1 ) {
+        for(int i = 0; i < _nDevices; ++i) {
+            if( _readBuffer[i] & 0x4000 ) {
+                return true;
+            }
+        }
+    } else if( device < _nDevices ) {
+        return (_readBuffer[device] & 0x4000) == 0x4000;
+    }
+    return false; 
+}
+
+
+void As5048Spi::frequency(int hz) 
+{
+    _spi.frequency(hz);
+}
+
+int As5048Spi::mask(int sensor_result)
+{
+    return sensor_result & 0x3FFF; // return lowest 14-bits
+}
+
+
+void As5048Spi::mask(int* sensor_results, int n)
+{
+    for(int i = 0; i < n; ++i) {
+        sensor_results[i] &= 0x3FFF;
+    }
+}
+
+
+bool As5048Spi::parity_check(int sensor_result)
+{
+    // Use the LSb of result to keep track of parity (0 = even, 1 = odd)
+    int result = sensor_result;
+    
+    for(int i = 1; i <= 15; ++i) {
+        sensor_result >>= 1;
+        result ^= sensor_result;
+    }
+    // Parity should be even
+    return (result & 0x0001) == 0;
+}
+
+const int* As5048Spi::read(As5048Command command)
+{
+    _read(command); // Send command to device(s)
+    return _read(AS_CMD_NOP); // Read-out device(s)
+}
+
+const int*  As5048Spi::read_sequential(As5048Command command)
+{
+    return _read(command);
+}
+
+const int*  As5048Spi::read_angle()
+{  
+    _read(AS_CMD_ANGLE); // Send command to device(s)
+    return _read(AS_CMD_NOP); // Read-out device(s)
+}
+
+const int*  As5048Spi::read_angle_sequential()
+{
+    return _read(AS_CMD_ANGLE); 
+}
+
+
+int* As5048Spi::_read(As5048Command command)
+{
+    if(_nDevices == 1)
+    {
+        // Give command to start reading the angle
+        _chipSelectN.write(0);
+        wait_us(1); // Wait at least 350ns after chip select
+        _readBuffer[0] = _spi.write(command);
+        _chipSelectN.write(1);
+        wait_us(1); // Wait at least 350ns after chip select       
+    } else
+    {
+        // Enable the sensor on the chain
+        _chipSelectN.write(0);
+         wait_us(1); // Wait at least 350ns after chip select
+        for(int i = 0; i < _nDevices; ++i)
+        {
+            _readBuffer[i] = _spi.write(command);
+        }
+        _chipSelectN.write(1);
+        wait_us(1); // Wait at least 350ns after chip select
+    }
+    return _readBuffer;
+}
+
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/as5048spi.h	Tue Oct 08 14:59:11 2019 +0000
@@ -0,0 +1,85 @@
+#include "mbed.h"
+typedef enum {
+    AS_FLAG_PARITY = 0x8000,
+    AS_FLAG_READ = 0x4000,
+} As5048Flag;
+
+typedef enum {
+    AS_CMD_NOP = 0x0000,
+    AS_CMD_ERROR = 0x0001 | AS_FLAG_READ,       // Reads error register of sensor and clear error flags
+    AS_CMD_DIAGNOSTICS = 0x3FFD |  AS_FLAG_READ, // Reads automatic gain control and diagnostics info
+    AS_CMD_MAGNITUDE = 0x3FFE | AS_FLAG_READ,
+    
+    AS_CMD_ANGLE = 0x3FFF| AS_FLAG_PARITY | AS_FLAG_READ,
+} As5048Command;
+
+// Masks for bits in the result of the AS_CMD_DIAGNOSTICS command
+typedef enum {
+    AS_DIAG_CORDIC_OVERFLOW = 0x0200,
+    AS_DIAG_HIGH_MAGNETIC = 0x0400,
+    AS_DIAG_LOW_MAGNETIC = 0x0800,
+} As5048Diagnostics;
+
+
+//! Class for interfacing with the AMS AS5048A magnetic rotary sensor over the SPI-interface.
+class As5048Spi
+{
+public:
+    As5048Spi(PinName mosi, PinName miso, PinName sclk, PinName chipselect, int nDevices = 1);
+    ~As5048Spi();
+    
+    bool error(int device = -1);
+    
+    /// Sets the SPI clock frequency in Hz. Maximum tested frequency is 10MHz.
+    void frequency(int frequency = 1000000);
+    
+    /// Sends a read command to the sensor.
+    const int* read(As5048Command command);
+    
+    /// Sends a read command to the sensor. 
+    /// A call to this function will not directly return the requested value. The
+    /// requested value will be returned in a next read_sequential call. 
+    /// Use this function to read sensor values with minimum speed impact on SPI-bus
+    /// and microcontroller.
+    const int* read_sequential(As5048Command command);
+    
+    /// Performs a single angle measurement on all sensors
+    /// @return Array of raw angle data. To get the 14-bit value representing
+    ///     the angle, apply the mask() to the result.
+    const int* read_angle();
+    
+    /// Performs sequential angle measurements on all sensors. The first time this
+    /// method is called the result is not usefull, the measurement data of the call
+    /// will be returned by the next call to this method.
+    /// @return Array of raw angle data. To get the 14-bit value representing
+    ///     the angle, apply the mask() to the result.
+    const int* read_angle_sequential();
+
+    /// Returns lowest 14-bits
+    static int mask(int sensor_result);
+
+    /// Applies the mask to the first n bytes in the read buffer (for daisychained sensors).
+    static void mask(int* sensor_results, int n);
+    
+    /// Checks if the return value from the sensor has the right parity
+    /// @return true if ok
+    static bool parity_check(int sensor_result);
+    
+    /// Returns an angle from 0 to 36000 (degrees times 100).
+    /// @param sensor_result is one of the values returned by read_angle or read_angle_sequential
+    static int degrees(int sensor_result);
+    
+    /// Returns an angle from 0 to 2*PI*100 
+    /// @param sensor_result is one of the values returned by read_angle or read_angle_sequential
+    static int radian(int sensor_result);
+    
+
+protected:
+    int _nDevices;
+    DigitalOut _chipSelectN;
+    SPI _spi;
+    
+    int* _readBuffer; // Stores the results of the last sequential read
+    
+    int* _read(As5048Command command);
+};

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Tue Oct 08 14:59:11 2019 +0000
@@ -0,0 +1,47 @@
+#include "mbed.h"
+#include "as5048spi.h"
+
+#define rayon_roue 0.0045
+#define pi 3.14159
+
+#define intervalle 0.005
+
+As5048Spi sensor(PB_15, PB_14, PB_13, PB_12);   //MOSI, MISO, SCKL, CS
+Serial pc(USBTX, USBRX); // tx, rx
+InterruptIn bouton(PC_13);
+Ticker timer;
+int angle, degrees_avant, degrees_maintenant, degrees_vitesse;
+float vitesse;
+
+void donnee_saisie()
+{
+    const int* angles = sensor.read_angle();
+    angle = angles[0];
+    //Récupération de l'angle précédent
+    degrees_avant = degrees_maintenant;
+        
+    //Aquisition du nouvel angle
+    degrees_maintenant = sensor.degrees(angle)/100;
+        
+    //Calcul de la différence
+    degrees_vitesse = (degrees_maintenant - degrees_avant) / intervalle;
+        
+    vitesse = (rayon_roue * degrees_vitesse * 2 * pi / 360) /*/ (5 + 0.01 / (2 * pi))*/;
+}
+
+void print_speed()
+{
+    timer.detach();
+    //Affichage du résultat
+    pc.printf("rotation = %d degrees/s, vitesse = %.4f mm/s     \r", degrees_vitesse, vitesse * 1000);
+    timer.attach(&donnee_saisie, intervalle); //Lancement de la fonction "donnee_saisie()" toutes les 1 sec
+}
+
+int main() {
+    bouton.rise(&print_speed);
+    timer.attach(&donnee_saisie, intervalle); //Lancement de la fonction "donnee_saisie()" toutes les 1 sec
+    while(1) 
+    {
+        
+    }
+}
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Tue Oct 08 14:59:11 2019 +0000
@@ -0,0 +1,1 @@
+https://os.mbed.com/users/mbed_official/code/mbed/builds/65be27845400
\ No newline at end of file