How to Use AS5047P: Examples, Pinouts, and Specs

The AS5047P is a high-resolution magnetic rotary position sensor designed to provide precise angular position measurements. With a 14-bit resolution, it ensures accurate and reliable performance in demanding applications. The sensor uses a contactless magnetic measurement principle, making it robust against environmental factors such as dust, dirt, and oil. It supports SPI and PWM communication interfaces, offering flexibility for integration into various systems.

• Robotics: Joint position sensing and feedback
• Industrial automation: Motor shaft position monitoring
• Motor control: Brushless DC (BLDC) and stepper motor position sensing
• Automotive: Steering angle and throttle position sensing
• Consumer electronics: Precision control systems

1. Power Supply: Connect the VDD3V3 or VDD5V pin to a 3.3V or 5V power source, respectively, and connect the GND pin to the ground.
2. Magnet Placement: Place a diametrically magnetized magnet above the sensor at a distance of 0.5 mm to 3 mm. Ensure the magnet is centered for accurate readings.
3. Communication Interface:
   • For SPI: Connect the CSn, CLK, MISO, and MOSI pins to the corresponding SPI pins on your microcontroller.
   • For PWM: Use the PWM pin to read the angular position as a duty cycle.
4. Incremental Encoder: Use the A, B, and Index pins if you need incremental encoder functionality.
5. Programming: If required, use the PROG pin to program the OTP memory.

• Ensure the magnetic field strength is within the specified range (30 mT to 70 mT) for accurate operation.
• Use decoupling capacitors (e.g., 100 nF) close to the power supply pins to reduce noise.
• Avoid placing ferromagnetic materials near the sensor, as they can distort the magnetic field.
• For high-speed applications, ensure the SPI clock frequency is configured correctly to avoid communication errors.

#include <SPI.h>

// Define SPI pins for the AS5047P
const int CSn = 10; // Chip Select pin connected to Arduino pin 10

void setup() {
  // Initialize SPI communication
  SPI.begin();
  pinMode(CSn, OUTPUT);
  digitalWrite(CSn, HIGH); // Set CSn high to deselect the sensor

  Serial.begin(9600); // Initialize serial communication for debugging
}

uint16_t readAngle() {
  uint16_t angle = 0;

  // Start SPI communication with the AS5047P
  digitalWrite(CSn, LOW); // Select the sensor
  delayMicroseconds(1);   // Short delay for stability

  // Send the command to read the angle (0x3FFF is the angle register)
  uint16_t command = 0x3FFF;
  uint8_t highByte = SPI.transfer((command >> 8) & 0xFF); // Send high byte
  uint8_t lowByte = SPI.transfer(command & 0xFF);         // Send low byte

  // Combine the received bytes into a 14-bit angle value
  angle = ((highByte << 8) | lowByte) & 0x3FFF;

  digitalWrite(CSn, HIGH); // Deselect the sensor
  return angle;
}

void loop() {
  uint16_t angle = readAngle(); // Read the angular position
  float degrees = (angle * 360.0) / 16384.0; // Convert to degrees (14-bit resolution)

  Serial.print("Angle: ");
  Serial.print(degrees);
  Serial.println(" degrees");

  delay(100); // Wait 100 ms before the next reading
}

1. No Output or Incorrect Readings:

   • Ensure the magnet is properly aligned and within the specified distance from the sensor.
   • Verify the power supply voltage and connections.
   • Check the SPI or PWM connections for loose or incorrect wiring.

2. Noise in Readings:

   • Add decoupling capacitors near the power supply pins.
   • Ensure the sensor is not exposed to strong external magnetic fields.

3. SPI Communication Fails:

   • Verify the SPI clock frequency and ensure it is within the sensor's supported range.
   • Check the CSn pin state during communication (it should be low when active).

4. PWM Output Not Detected:

   • Ensure the PWM pin is connected to the correct input on your microcontroller.
   • Verify the microcontroller's PWM reading configuration.

Q: Can the AS5047P be used with a 5V microcontroller?
A: Yes, the AS5047P supports both 3.3V and 5V power supplies, making it compatible with 5V microcontrollers.

Q: What type of magnet should I use?
A: Use a diametrically magnetized magnet with a magnetic field strength of 30 mT to 70 mT.

Q: How do I calculate the angle from the PWM output?
A: Measure the duty cycle of the PWM signal. The angle is proportional to the duty cycle, where 0% corresponds to 0° and 100% corresponds to 360°.