MCF8316A: Motor is not spinning without uC

I want to specify that I apply an analog voltage between 2.3-3V to the speed pin

Hi Vinsch,

Have you configured/tuned the MCF8316A registers for your motor? The MCF8316A requires some basic tuning in its register settings, specific to your motor, before you can spin up the motors.

If you are to use it without an external microcontroller, then the register settings need to be programmed into the device's internal EEPROM register memory so that they will be loaded on power-up. The registers can be configured/programmed using I2C (see datasheet section 7.6 EEPROM access and I2C interface).

These basic essential settings include:

• Motor Parameters
  • Motor Phase Resistance [MOTOR_RES]
  • Motor Phase Inductance [MOTOR_IND]
  • Motor BEMF Constant [MOTOR_BEMF_CONST]
  • Speed Loop Kp [SPD_LOOP_KP]
  • Speed Loop Ki [SPD_LOOP_KI]
  • If a speed command is given while any of these 5 parameters above are 0, then device will automatically attempt to run it's built in Motor Parameter Extraction Tool (MPET) algorithm to measure these values.
  • If MPET fails to measure these values, you may need to enter these parameters manually. See this E2E FAQ for more details.
• Maximum Speed [MAX_SPEED]

There are many other register settings that you'll want to tune and optimize for your motor/application, such as various current limits, acceleration rates, fault configs etc.

Please refer to the MCF8316A Tuning Guide for instructions on how to tune various parameters.

Regards,
Eric C.

Hi, so I tried to program the registries as you said [using Arduino UNO] and I used this code that I found on a forum:

#include <Wire.h>

const int deviceAddress = 0x01;

void setup() {

  int error, n;

  Wire.begin();

  Wire.setClock(50000);      // 50kHz, half the normal speed

  Serial.begin(115200);

  Serial.println("Starting");

  // ------------------------------------------------

  // Write data to a register

  // ------------------------------------------------

  const byte control_word1[] = {0x02, 0x50, 0x00, 0x8A}; // <--- set the right numbers

  const byte data1[] = {0x00, 0x00, 0x00, 0x00};   // <-- set the right numbers

  Wire.beginTransmission(deviceAddress);

  Wire.write(control_word1, 3);

  Wire.write(data1, 4);

  error = Wire.endTransmission();

  if(error == 0)

  {

    Serial.println("Data succesfully sent");

  }

  delay(1);               // the chip needs some time ?

  // ------------------------------------------------

  // Read data from a register

  // ------------------------------------------------

  const byte control_word2[] = {0x02, 0x50, 0x00, 0x8A};  // <--- set the right numbers

  Wire.beginTransmission(deviceAddress);

  Wire.write(control_word2, 3);

  error = Wire.endTransmission(false);   // 'false' for a repeated start

  if(error == 0)

  {

    Serial.println("Register succesfully selected");

  }

  delay(1);               // the chip needs some time ?

  n = Wire.requestFrom(deviceAddress, 4);

  if(n == 4)

  {

    Serial.println("Data received");

    for( int i=0; i<4; i++)

    {

      Serial.print("0x");

      Serial.print(Wire.read(), HEX);

      Serial.print(", ");

    }

    Serial.println();

  }

  delay(1);               // the chip needs some time ?

}

void loop() {}

Could you please check if it's good? I don't really know how to form the control word for writing values in closed loop2, 3, 4 for motor_res, motor_ind, motor_bmef, speed_loop_kp, speed_loop_ki. What values should these last 2 parameters have [speed_loop_kp, speed_loop_ki]?

Hi Vinsch,

Just want to confirm that you don't have a MCF8316AEVM correct? The EVM + GUI is probably the easiest way to configure/tune the device registers for your motor.

Regarding to your Arduino code, I'm not sure, but the Wire.write() command probably sends the start condition along with the target address and R/W bit automatically, so you might only need to provide the 24-bit control word. Also, I would set CRC_EN to 0 to avoid needing to calculate/transmit the additional CRC byte. So I would try changing your control_word1[] = {0x10, 0x00, 0x8A};

You can also refer to this E2E FAQ on using a MSP430FR2355 LaunchPad to program/communicate with the MCx devices using I2C:
https://e2e.ti.com/support/motor-drivers-group/motor-drivers/f/motor-drivers-forum/1246892/faq-program-mcx-bldc-motor-driver-through-i2c-using-msp430-launchpad

Using the example project for MSP430FR2355 LaunchPad, you should easily be able to modify the code to read/write to any registers in the MCF8316A device.

Regards,
Eric C.

Hi Vinsch,

Could you please try the following code on your Arduino:

#include <Wire.h>

void setup()
{
  Serial.begin(115200);
  
  Wire.begin();
  Wire.setClock(100000);
  
  read32(0x80);  // 32-bit read register 0x80
  write32(0x80, 0x12345678);  // 32-bit write  to register 0x80
  read32(0x80);  // 32-bit read register 0x80
}

void loop()
{
}

void read32(int reg_addr)
{
  byte reg_addr_H = (reg_addr & 0x0F00) >> 8;
  byte reg_addr_L = (reg_addr & 0xFF);
  
  const byte control_word[] = {0x90, reg_addr_H, reg_addr_L}; // 24-bit control word (CRC_EN = 0)
 
  Wire.beginTransmission(0x01);
  Wire.write(control_word, 3); // send the control word
  Wire.endTransmission();

  Wire.requestFrom(0x01, 4);    // request 4 bytes (32-bit read)

  unsigned long register_value = 0;
  for (int i = 0; i < 4; i++)
  {
    unsigned long c = Wire.read(); // receive a byte as character
    register_value |= (c << (i * 8)); // reconstruct 32-bit value (LSB is received first)
//    Serial.println(c, HEX);         // print each received byte
  }
  
  Serial.print("Finished reading register: 0x");
  Serial.println(reg_addr, HEX);
  Serial.print("Value = 0x");
  Serial.println(register_value, HEX);
}

void write32(int reg_addr, unsigned long writedata)
{
  byte reg_addr_H = (reg_addr & 0x0F00) >> 8;
  byte reg_addr_L = (reg_addr & 0xFF);
  
  const byte control_word[] = {0x10, reg_addr_H, reg_addr_L}; // 24-bit control word (CRC_EN = 0)
  byte data[] = {0x00, 0x00, 0x00, 0x00};   // 32-bit register data to be written
 
  for (int i = 0; i < 4; i++)
  {
    data[i] = ((writedata & (((unsigned long)0xFF) << (i * 8))) >> (i * 8));
  }
 
  Wire.beginTransmission(0x01);
  Wire.write(control_word, 3); // send the control word
  Wire.write(data, 4);  // send the 32-bit write data
  Wire.endTransmission();

  Serial.print("Finished writing to register: 0x");
  Serial.println(reg_addr, HEX);
}

I created a simple read and write functions and verified that they work on my MSP430FR2355 LaunchPad

Regards,
Eric C.

Hello Eric,

Yes I don't have the EVM Board

I tried the code and this results in the serial monitor:

Finished reading register: 0x80

Value = 0x12345678

Finished writing to register: 0x80

Finished reading register: 0x80

Value = 0x12345678


What should I do next? Can you please make this code to change the necessary parameters ? 
(motor_res, motor_ind, motor_bemf, speed_loop_kp, speed_loop_ki)
in the registers ClOSED_LOOP2, CLOSED_LOOP3 and CLOSED_LOOP4? 

I understood from the datasheet that the addresses are 0x8A; 0x8C; 0x8E

In the end I just want the motor to spin or at least have some feedback on the phases to be able to measure it