Diff: As5048.h

Revision:

5:9df31d15f3fa

Parent:

4:56d59ce73270

--- a/As5048.h	Tue Aug 23 15:11:48 2016 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,351 +0,0 @@
-#ifndef _AS5048_H_
-#define _AS5048_H_
-
-#include "mbed.h"
-/**
- * Interfacing with the AMS AS5048A magnetic rotary sensor using SPI protocol
- * AS5048 uses 16-bit transfer;
- * We use two 8-bit transfers for compatibility with 8-bit SPI master devices
- * SPI protocol:
- *   Mode = 1: 
- *   clock polarity = 0 --> clock pulse is high
- *   clock phase = 1 --> sample on falling edge of clock pulse
- * Code was succesfully tested on the FRDM KL25Z and K22F. The same code fails
- * on the K64F for some reason. Sampling using a logic analyzer does however
- * show the same results for al three boards.
- */
-class As5048 {
-
-
-public:
-
-    static const int kNumSensorBits        = 14;      // 14-bits sensor
-    static const uint16_t kCountsPerRev    = 0x4000;  // 2**NUM_SENSOR_BITS
-    static const uint16_t kMask            = 0x3FFF;  // 2**NUM_SENSOR_BITS - 1
-    static const int kParity               = 1;       // even parity
-    
-    static const int kSpiFrequency         = 1000000; // AS5048 max 10 MHz
-    static const int kSpiBitsPerTransfer   = 8;
-    static const int kSpiMode              = 1;
-    
-    static const float kDegPerRev          = 360.0f;  // 360 degrees/rev
-    static const float kRadPerRev          = 6.28318530718f; // 2*pi rad/rev
-
-    // AS5048 flags
-    typedef enum {
-        AS_FLAG_PARITY          = 0x8000,
-        AS_FLAG_READ            = 0x4000,
-    } As5048Flag;
-    
-    // AS5048 commands
-    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;
-    
-    // AS5048 diagnostics
-    typedef enum {
-        AS_DIAG_CORDIC_OVERFLOW = 0x0200,
-        AS_DIAG_HIGH_MAGNETIC   = 0x0400,
-        AS_DIAG_LOW_MAGNETIC    = 0x0800,
-    } As5048Diagnostics;
-
-    /**
-     * Creates an object of num_sensors daisy chained AS5048 sensors;
-     * default number of sensors in chain is 1
-     * @param mosi: pinname of the mosi pin of the spi communication
-     * @param miso: pinname of the miso pin of the spi communication
-     * @param sck: pinname of the clock pin of the spi communication
-     * @param cs: pinname of the chip select pin of the spi communication
-     * @param num_sensors = 1: number of sensors in daisy chain
-     */
-    As5048(PinName mosi, PinName miso, PinName sck, PinName cs, int num_sensors = 1):
-        kNumSensors_(num_sensors),
-        chip_(cs),
-        spi_(mosi, miso, sck) 
-    {
-        DeselectChip();
-        
-        spi_.format(kSpiBitsPerTransfer, kSpiMode);
-        spi_.frequency(kSpiFrequency);
-        
-        read_buffer_  = new uint16_t[kNumSensors_];
-        angle_buffer_ = new uint16_t[kNumSensors_];
-        angle_offset_ = new uint16_t[kNumSensors_];
-        directions_ = new bool[kNumSensors_];
-        
-        for (int i=0; i<kNumSensors_; ++i) {
-            read_buffer_[i] = 0;
-            angle_buffer_[i] = 0;
-            angle_offset_[i] = 0;
-            directions_[i] = true;
-        }
-        
-        last_command_ = AS_CMD_NOP;
-    }
-
-    
-    /**
-     * Destructor, memory deallocation
-     */
-    ~As5048() 
-    {
-        delete [] read_buffer_;
-        delete [] angle_buffer_;
-        delete [] angle_offset_;
-        delete [] directions_;
-    }
-        
-    /**
-     * Parity check
-     * @param n: integer to check
-     * @return: true if ok
-     */
-    static bool CheckParity(int n) 
-    {
-        int parity = n;
-        for(int i=1; i <= kNumSensorBits+1; ++i) {
-            n >>= 1;
-            parity ^= n;
-        }
-        return (parity & kParity) == 0;
-    }
-    
-    /**
-     * Update the buffer with angular measurements
-     * NOTE 1:
-     *  If the last command sent through Transfer was *not* AS_CMD_ANGLE
-     *  then we need an additional Transfer; this takes more time!
-     *  This should not occur, since Transfer is not *yet* used elsewhere.
-     * NOTE 2:
-     *  We run a parity check on the results from the transfer. We only 
-     *  update the angle_buffer_ with values that pass the parity check.
-     * Measurement using Timer on K64F  for last_command_ == AS_CMD_ANGLE
-     * shows this function takes 87 or 88 us.
-     */
-    void UpdateAngleBuffer() 
-    {
-        // ensure that the new results indeed will be angles
-        if (last_command_ != AS_CMD_ANGLE) {
-            Transfer(AS_CMD_ANGLE);
-        }
-        
-        // update the read buffer
-        Transfer(AS_CMD_ANGLE); 
-        
-        // update the angle buffer with parity checked values
-        for (int i=0; i<kNumSensors_; ++i) {
-            if (CheckParity(read_buffer_[i])) {
-                // only update angles when parity is correct
-                angle_buffer_[i] = read_buffer_[i];
-            }
-        }
-    }
-    
-    /**
-     * @return: pointer to read_buffer_
-     */
-    const uint16_t* get_read_buffer()  { return read_buffer_; }
-    
-    /**
-     * @return: pointer to angle_buffer_
-     */
-    const uint16_t* get_angle_buffer() { return angle_buffer_; }
-    
-    /**
-     * @return: pointer to angle_offet_
-     */
-    const uint16_t* get_angle_offset() { return angle_offset_; }
-    
-    /**
-     * @return: pointer to directions_
-     */
-    const bool * get_directions_() { return directions_;}
-    
-    /**
-     * You get the angles from two UpdateAngleBuffer() calls before
-     * @return: 14 bits absolute position
-     */
-    int getAngle(int i_sensor=0)
-    { 
-        int ans = ((int) (angle_buffer_[i_sensor] & kMask)) - angle_offset_[i_sensor];
-        return directions_[i_sensor]?ans:-ans;
-    }
-    
-    /**
-     * You get the angles from two UpdateAngleBuffer() calls before
-     * @return: revolution ratio in [0,1]
-     */
-    float getAngleRatio(int i_sensor=0)      { return (float) getAngle(i_sensor) / kCountsPerRev; }
-    
-    /**
-     * You get the angles from two UpdateAngleBuffer() calls before
-     * @return: angle in degrees
-     */
-    float getAngleDegrees(int i_sensor=0)    { return getAngleRatio(i_sensor) * kDegPerRev; }
-    
-    /**
-     * You get the angles from two UpdateAngleBuffer() calls before
-     * @return: angle in radians
-     */
-    float getAngleRadians(int i_sensor=0)    { return getAngleRatio(i_sensor) * kRadPerRev; }
-    
-    /**
-     * Set direction for a sensor
-     * @param i_sensor: id of sensor for which the offset is to be set
-     * @param dir: true positive, false negative
-     * @return: true if i_sensor in [0,kNumSensor_)
-     */
-    bool setDirection(int i_sensor, bool dir) 
-    {
-        if (i_sensor>-1 and i_sensor<kNumSensors_) {
-            directions_[i_sensor] = dir;
-            return true;
-        }
-        return false;
-    }
-    
-    /**
-     * Set direction for the first sensor
-     * @param dir: true positive, false negative
-     * @return: true if i_sensor in [0,kNumSensor_)
-     */
-    bool setDirection(bool dir) 
-    {
-        return setDirection(0,dir);
-    }
-    
-    
-    /**
-     * Set offset for a sensor
-     * @param i_sensor: id of sensor for which the offset is to be set
-     * @param offset: offset in counts [0,2**14-1]
-     * @return: true if i_sensor in [0,kNumSensor_)
-     */
-    bool setOffset(int i_sensor, uint16_t offset) 
-    {
-        if (i_sensor>-1 and i_sensor<kNumSensors_) {
-            angle_offset_[i_sensor] = offset;
-            return true;
-        }
-        return false;
-    }
-    
-    /**
-     * Set offset for the first sensor
-     * @param offset: offset in counts [0,2**14-1]
-     * @return: true if i_sensor in [0,kNumSensor_)
-     */
-    bool setOffset(uint16_t offset) { return setOffset(0,offset); }
-    
-    /**
-     * Set offset for a sensor
-     * @param i_sensor: id of sensor for which the offset is to be set
-     * @param offset_ratio: offset in ratio in [0,1]
-     * @return: true if i_sensor in [0,kNumSensor_)
-     */
-    bool setOffsetRatio (int i_sensor, float offset_ratio) 
-    {
-        return setOffset(i_sensor,offset_ratio*kCountsPerRev);
-    }
-    
-    /**
-     * Set offset for the first sensor
-     * @param offset_ratio: offset in ratio in [0,1]
-     * @return: true if i_sensor in [0,kNumSensor_)
-     */
-    bool setOffsetRatio(float offset_ratio) 
-    { 
-        return setOffsetRatio(0,offset_ratio); 
-    }
-    
-    /**
-     * Set offset for a sensor
-     * @param i_sensor: id of sensor for which the offset is to be set
-     * @param offset_degrees: offset in degrees in [0,360]
-     * @return: true if i_sensor in [0,kNumSensor_)
-     */
-    bool setOffsetDegrees(int i_sensor, float offset_degrees) 
-    {
-        return setOffsetRatio(i_sensor,offset_degrees / kDegPerRev);
-    }
-    
-    /**
-     * Set offset for the first sensor
-     * @param offset_degrees: offset in degrees in [0,360]
-     * @return: true if i_sensor in [0,kNumSensor_)
-     */
-    bool setOffsetDegrees(float offset_degrees) 
-    {
-        return setOffsetDegrees(0, offset_degrees);
-    }
-    
-    /**
-     * Set offset for a sensor
-     * @param i_sensor: id of sensor for which the offset is to be set
-     * @param offset_radians: offset in radians in [0,2*pi]
-     * @return: true if i_sensor in [0,kNumSensor_)
-     */
-    bool setOffsetRadians(int i_sensor, float offset_radians) 
-    {
-        return setOffsetRatio(i_sensor, offset_radians / kRadPerRev);
-    }
-    
-    /**
-     * Set offset for the first sensor
-     * @param offset_radians: offset in radians in [0,2*pi]
-     * @return: true if i_sensor in [0,kNumSensor_)
-     */
-    bool setOffsetRadians(float offset_radians) 
-    {
-        return setOffsetRadians(0, offset_radians);
-    }
-    
-    
-   
-
-protected:
-
-
-
-    /**
-     * Select (low) chip, and wait 1 us (at least 350 ns)
-     */
-    void SelectChip()   { chip_.write(0); wait_us(1); }
-    
-    /**
-     * Deselect (high) chip, and wait 1 us (at least 350 ns)
-     */
-    void DeselectChip() { chip_.write(1); wait_us(1); }
-
-    /**
-     * SPI transfer between each of the daisy chained sensors
-     * @param cmd: Command to send
-     */
-    void Transfer(As5048Command cmd) 
-    {
-        SelectChip();
-        for(int i=0; i<kNumSensors_; ++i){
-            read_buffer_[i]  = spi_.write(cmd>>8) << 8;
-            read_buffer_[i] |= spi_.write(cmd & 0x00FF);
-        }
-        DeselectChip();
-        last_command_ = cmd;
-    }
-
-    const int kNumSensors_;     // number of sensors in daisy chain
-    DigitalOut chip_;           // chip select port
-    SPI spi_;                   // mbed spi communiation object
-    
-    uint16_t* read_buffer_;     // buffer for results from last transfer
-    uint16_t* angle_buffer_;    // buffer for angle results from last transfer
-    uint16_t* angle_offset_;    // offset array for each sensor
-    bool* directions_;          // direction true positive, false negative
-    
-    As5048Command last_command_;// command sent during last Transfer
-    
-};
-#endif
\ No newline at end of file