ma735

MA735 SimpleFOC driver

This is based on the MA730 driver in SimpleFOC, with some tweaks to support the unique registers and options of the MA735. It is a little bit inferior, but less expensive chip after all. The advantage however of this chip (besides cost) is that resolution is inversely proportional to reading speed, ranging from 9-13 bit resolution and 64us to 16ms read times.

Hardware setup

Connect as per normal for your SPI bus. No special hardware setup is needed to use this driver.

Software setup

Its actually easier to use than the standard SPI sensor class, because it is less generic:

#include "Arduino.h"
#include "Wire.h"
#include "SPI.h"
#include "SimpleFOC.h"
#include "SimpleFOCDrivers.h"
#include "encoders/ma735/MagneticSensorMA735.h"

#define SENSOR1_CS 5 // some digital pin that you're using as the nCS pin
MagneticSensorMA735 sensor1(SENSOR1_CS);


void setup() {
    sensor1.init();
}

Set some options:

MagneticSensorMA735 sensor1(SENSOR1_CS, mySPISettings);

Use another SPI bus:

void setup() {
    sensor1.init(&SPI2);
}

Set some registers before start

void setup() {
    sensor1.init();
    
    // Note that with this driver there is a write check so registers are not written to if the value is the exact same. Other drivers do not have a write check, and you can easily wear out the NVM every time the code is run. 1,000 cycles max.
    sensor1.setResolution(10.0);
}

Here's how you can use it:

    // update the sensor (only needed if using the sensor without a motor)
    sensor1.update();

    // get the angle, in radians, including full rotations
    float a1 = sensor1.getAngle();

    // get the velocity, in rad/s - note: you have to call getAngle() on a regular basis for it to work
    float v1 = sensor1.getVelocity();

    // get the angle, in radians, no full rotations
    float a2 = sensor1.getCurrentAngle();

    // get the field strength
    FieldStrength fs = sensor1.getFieldStrength();
    Serial.print("Field strength: ");
    Serial.println(fs);

	//get the calculated resolution from FilterWindow register
    float res = sensor.getResolution();
  	Serial1.print("Resolution: ");
  	Serial1.println(res);

	//get the calculated update time in micro seconds from the FilterWindow register
  	int Time = sensor.getUpdateTime();
  	Serial1.print("Update Time (microsecs): ");
  	Serial1.println(Time);