adding support for MA730, exposing clock_speed and providing additional constructors

Author: owennewo

src/MagneticSensorI2C.cpp

@@ -22,13 +22,22 @@ MagneticSensorI2C::MagneticSensorI2C(uint8_t _chip_address, int _bit_resolution,
   // extraction masks
   lsb_mask = (uint8_t)( (2 << lsb_used) - 1 );
   msb_mask = (uint8_t)( (2 << _bits_used_msb) - 1 );
+  clock_speed = 400000;
+  sda_pin = SDA;
+  scl_pin = SCL;
+
+}
+
+MagneticSensorI2C MagneticSensorI2C::AS5600() {
+  MagneticSensorI2C* sensor = new MagneticSensorI2C(0x36, 12, 0x0E, 4);
+  return *sensor;
 }
 
 
 void MagneticSensorI2C::init(){
 
 	//I2C communication begin
-	Wire.begin();
+	Wire.begin(sda_pin, scl_pin, clock_speed);
 
 	// velocity calculation init
 	angle_prev = 0;

src/MagneticSensorI2C.h

@@ -17,8 +17,9 @@ class MagneticSensorI2C: public Sensor{
      * @param _bits_used_msb number of used bits in msb
      */
     MagneticSensorI2C(uint8_t _chip_address, int _bit_resolution, uint8_t _angle_register_msb, int _msb_bits_used);
-    
 
+    static MagneticSensorI2C AS5600();
+    
     /** sensor initialise pins */
     void init();
 
@@ -41,7 +42,15 @@ class MagneticSensorI2C: public Sensor{
     int hasAbsoluteZero();
     /** returns 0  maning it doesn't need search for absolute zero */
     int needsAbsoluteZeroSearch();
+
+    /* the speed of the i2c clock signal */
+    long clock_speed;
+
+    /* the pin used for i2c data */
+    int sda_pin;
 
+    /* the pin used for i2c clock */
+    int scl_pin;
 
   private:
     float cpr; //!< Maximum range of the magnetic sensor

src/MagneticSensorSPI.cpp

@@ -11,23 +11,42 @@ MagneticSensorSPI::MagneticSensorSPI(int cs, float _bit_resolution, int _angle_r
   angle_register = _angle_register ? _angle_register : DEF_ANGLE_REGISTAR;
   // register maximum value (counts per revolution)
   cpr = pow(2,_bit_resolution);
+  spi_mode = SPI_MODE1;
+  clock_speed = 1000000;
+  
+  command_parity_bit = 15; // for backwards compatibilty
+  command_read_bit = 14; // for backwards compatibilty
+}
+
+MagneticSensorSPI MagneticSensorSPI::MA730(int cs) {
+  MagneticSensorSPI* sensor = new MagneticSensorSPI(cs, 14, 0xFFFF);
+  sensor->spi_mode = SPI_MODE0;
+  sensor->command_parity_bit = 0;  // parity bit insertion not implemented
+  sensor->command_read_bit = 0;  // read flag bit insertion not implemented
+  return *sensor;
+}
 
+MagneticSensorSPI MagneticSensorSPI::AS5147(int cs) {
+  MagneticSensorSPI* sensor = new MagneticSensorSPI(cs, 14, 0xCFFF);
+  sensor->spi_mode = SPI_MODE1;
+  sensor->command_parity_bit = 15; 
+  sensor->command_read_bit = 14;
+  return *sensor;
 }
 
 
 void MagneticSensorSPI::init(){
 	// 1MHz clock (AMS should be able to accept up to 10MHz)
-	settings = SPISettings(1000000, MSBFIRST, SPI_MODE1);
+	settings = SPISettings(clock_speed, MSBFIRST, spi_mode);
 
 	//setup pins
 	pinMode(chip_select_pin, OUTPUT);
-
 
 	//SPI has an internal SPI-device counter, it is possible to call "begin()" from different devices
 	SPI.begin();
 #ifndef ESP_H // if not ESP32 board
 	SPI.setBitOrder(MSBFIRST); // Set the SPI_1 bit order
-	SPI.setDataMode(SPI_MODE1) ;
+	SPI.setDataMode(spi_mode) ;
 	SPI.setClockDivider(SPI_CLOCK_DIV8);
 #endif
 
@@ -77,7 +96,7 @@ float MagneticSensorSPI::getVelocity(){
   float angle_c = getAngle();
   // velocity calculation
   float vel = (angle_c - angle_prev)/Ts;
-  
+
   // save variables for future pass
   angle_prev = angle_c;
   velocity_calc_timestamp = now_us;
@@ -147,35 +166,28 @@ byte MagneticSensorSPI::spiCalcEvenParity(word value){
   * Returns the value of the register
   */
 word MagneticSensorSPI::read(word angle_register){
-	word command = 0b0100000000000000; // PAR=0 R/W=R
-	command = command | angle_register;
 
-	//Add a parity bit on the the MSB
-	command |= ((word)spiCalcEvenParity(command)<<15);
-
-	//Split the command into two bytes
-	byte right_byte = command & 0xFF;
-	byte left_byte = ( command >> 8 ) & 0xFF;
+  word command = angle_register;
 
+  if (command_read_bit > 0) {
+    command = angle_register | (1 << command_read_bit);
+  }
+  if (command_parity_bit > 0) {
+   	//Add a parity bit on the the MSB
+  	command |= ((word)spiCalcEvenParity(command) << command_parity_bit);
+  }
 
 #if !defined(_STM32_DEF_) // if not stm chips
   //SPI - begin transaction
   SPI.beginTransaction(settings);
 #endif
-  //SPI - begin transaction
-  //SPI.beginTransaction(settings);
 
   //Send the command
   digitalWrite(chip_select_pin, LOW);
-#ifndef ESP_H // if not ESP32 board
   digitalWrite(chip_select_pin, LOW);
-#endif
-  SPI.transfer(left_byte);
-  SPI.transfer(right_byte);
+  SPI.transfer16(command);
   digitalWrite(chip_select_pin,HIGH);
-#ifndef ESP_H // if not ESP32 board
   digitalWrite(chip_select_pin,HIGH);
-#endif
 
 #if defined( ESP_H ) // if ESP32 board
   delayMicroseconds(50);
@@ -186,8 +198,7 @@ word MagneticSensorSPI::read(word angle_register){
   //Now read the response
   digitalWrite(chip_select_pin, LOW);
   digitalWrite(chip_select_pin, LOW);
-  left_byte = SPI.transfer(0x00);
-  right_byte = SPI.transfer(0x00);
+  word register_value = SPI.transfer16(0x00);
   digitalWrite(chip_select_pin, HIGH);
   digitalWrite(chip_select_pin,HIGH);
 
@@ -197,7 +208,7 @@ word MagneticSensorSPI::read(word angle_register){
 #endif
 
 	// Return the data, stripping the parity and error bits
-	return (( ( left_byte & 0xFF ) << 8 ) | ( right_byte & 0xFF )) & ~0xC000;
+	return register_value & ~0xC000;
 }
 
 /**

src/MagneticSensorSPI.h

@@ -17,7 +17,9 @@ class MagneticSensorSPI: public Sensor{
      * @param angle_register  (optional) angle read register - default 0x3FFF
      */
     MagneticSensorSPI(int cs, float bit_resolution, int angle_register = 0);
-    
+
+    static MagneticSensorSPI MA730(int cs);
+    static MagneticSensorSPI AS5147(int cs);
 
     /** sensor initialise pins */
     void init();
@@ -41,6 +43,11 @@ class MagneticSensorSPI: public Sensor{
     int hasAbsoluteZero();
     /** returns 0  maning it doesn't need search for absolute zero */
     int needsAbsoluteZeroSearch();
+    // returns the spi mode (phase/polarity of read/writes) i.e one of SPI_MODE0 | SPI_MODE1 | SPI_MODE2 | SPI_MODE3
+    int spi_mode;
+    
+    /* returns the speed of the SPI clock signal */
+    long clock_speed;
 
 
   private:
@@ -72,6 +79,9 @@ class MagneticSensorSPI: public Sensor{
     // velocity calculation variables
     float angle_prev; //!< angle in previous velocity calculation step
     long velocity_calc_timestamp; //!< last velocity calculation timestamp
+    
+    int command_parity_bit; //!< the bit where parity flag is stored in command
+    int command_read_bit; //!< the bit where read flag is stored in command
 
 };