Hello, I have a problem with rotating motor using MCT8316AEVM. I was able to drive a motor with analog input and I2C input modes. However, I could not start rotating a motor with PWM input and frequency input modes. I used a function generator(FG) to send a signal. I connected a positive pole of FG to SPEED_IN pin and a negative pole of FG to SPEED pin. Could you tell me whether it is wrong or not? Thank you.
Hello,
Thanks for posting your question in MD forum. Can you share the frequency of the PWM input signal generated from function generator? Is speed input mode configured to "PWM input mode (varying PWM duty cycle)" or "Frequency based speed input mode (varying PWM frequency)"? MCT8316A does not have "SPEED_IN" pin. Refer to the pin diagram below. If you are using the MCT8316AEVM, you should firstly configure the Jumper J1 (SPEED_SEL) to EXT and connect positive terminal of Function generator to EXT_SPEED test point and negative terminal to AGND. Jumper J1 can be located at the top left (below the 3 switches) of the MCT8316AEVM.
Regards,
Vishnu.
Hideyuki,
In frequency based mode, motor speed varies linearly as a function of the frequency of the square wave input at SPEED pin as given in below screenshot. Input frequency greater than INPUT_MAX_FREQUENCY clamps the duty command to 100%.
Please program the INPUT_MAX_FREQUENCY (located in DEVICE_CONFIG register) and vary the PWM frequency to observe change in motor speed.
Regards,
Vishnu
Hi Hideyuki,
In the MCT8316A GUI homepage, click "View register map" and input the maximum frequency value in Hz in the highlighted box shown in below image. Please make sure you convert the frequency in Hz from decimal to hexadecimal.
Regards,
Vishnu
