CCS/TMS320F28379S: abnormal noise when toggle gpio9 and gpio22

Feng CHEN

Expert 1670 points

Part Number: TMS320F28379S

Tool/software: Code Composer Studio

Hi ti experts,

i am using tms320f28379s to develop motor control board, ccs version is: v7.4.0.

an abnormal thing is found:

gpio9 and gpio22 are used to control two led lights

my question is: when motor runs on current close loop and let led flash with 1seconds interval, i can hear there is noise come out from motor.

but if stop led, the noise disappeared.

i am confused with this issue. the two gpio9 and gpio22 are only connected to control two led, i have no ideal why it is related to motor control.

pls help give some advice. thanks very much.

Feng

over 6 years ago

0 Cody Watkins over 6 years ago

TI__Mastermind 42195 points

Feng,

is this a TI designed motor control board or a custom board that you developed?

Either way it sounds like however the LED flash as been implemented is changing the stimulus given to the motor. I don't think it would be changing the PWM output(duty, phase, or period) in an obvious way. What I think it might be doing is slowing down how quickly the control loop can updated the PWM values and therefore are developing some sort of harmonic or distortion which is causing the noise. It really depends on how the control loop code and LED blink code has been written.

Unfortunately I am not an expert here, so if you need too much more guidance I may have to point you to another person.

Regards,
Cody

0 Feng CHEN over 6 years ago in reply to Cody Watkins

Expert 1670 points

Hi Cody,

thanks for your reply. pls help me and introduce the person to me. thanks.

Feng

0 Cody Watkins over 6 years ago in reply to Feng CHEN

TI__Mastermind 42195 points

Feng,

is this a custom developed board, or is this a TI evaluation module?

Thanks,
Cody

0 Feng CHEN over 6 years ago in reply to Cody Watkins

Expert 1670 points

Hi Cody,

it's our developed board.

Feng

0 Cody Watkins over 6 years ago in reply to Feng CHEN

TI__Mastermind 42195 points

Feng,

we are getting this thread over to an expert, expect a response soon.

Regards,
Cody

0 Yanming Luo over 6 years ago in reply to Cody Watkins

TI__Guru** 117290 points

It seems like the issue could be from the PCB layout of your own board. Please check if there are any coupling noises from these two GIPs on the PWM or ADC used by the motor control.

1. You might try to decrease the current through the LED by increasing the drive resistor to see what happens.

2. Run the motor using the open-loop control without current feedback signals to see if there is still noise on the motor and check the current feedback signals when enable and disable toggling these two GPIOs.

0 Feng CHEN over 6 years ago in reply to Yanming Luo

Expert 1670 points

thanks very much for your advice. i will try soon.

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CCS/TMS320F28379S: abnormal noise when toggle gpio9 and gpio22