MSP430FR6047: there is a problem with the ultrasonic echo signal captured by the ADC

Yale Li 李耀先

Part Number: MSP430FR6047
Other Parts Discussed in Thread: EVM430-FR6047

Hi Team,

Here is an issue related to USS need your help:

As shown in the figure, when using MSP430FR6047 to measure water flow, why does the ultrasonic echo shift toward the negative half axis? The zero point of the normal waveform should coincide with the horizontal axis, right? I am using my own board. Is there any way to improve the echo signal?

Thanks & Regards

over 1 year ago

0 Gary Gao over 1 year ago

TI__Mastermind 39650 points

Hi Yale,

It seems you do not put the figure here. Could you please reload it?

0 Yale Li 李耀先 over 1 year ago in reply to Gary Gao

TI__Expert 4660 points

Thanks Gary

0 Cash Hao11 over 1 year ago in reply to Yale Li 李耀先

TI__Mastermind 46435 points

Hi,

This kind of the DC offset on the ADC capture signal should be fine. Could you share the screenshots about your configuration page?

You can also enable USS_APP_DC_OFFSET_CANCELLATION_ENABLE in the code to avoid the influence.

Best regards,

Cash Hao

0 Yale Li 李耀先 over 1 year ago in reply to Cash Hao11

TI__Expert 4660 points

--Thanks Cash,

Cash Hao11 said:
Could you share the screenshots about your configuration page?

With the same configuration and ultrasonic sensor, the customer found that on his own board, there was more noise in the signal, while on TI's EVM430-FR6047 board, the signal waveform was smoother.

Is there any way to avoid too much noise in the signal?

The picture below is the signal measured on the EVM430-FR6047 board:

0 Cash Hao11 over 1 year ago in reply to Yale Li 李耀先

TI__Mastermind 46435 points

Hi,

The PCB layout could introduce more noise in to the system. Please refer to this link chapter 4.3 PCB layout recommendation.https://www.ti.com/lit/ug/tidudn0/tidudn0.pdf

Best regards,

Cash Hao

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MSP430FR6047: there is a problem with the ultrasonic echo signal captured by the ADC