MSP430FR2676: Fcapclk Parameter and Frequency Shift Settings Inquiry

Hello DDdoor,

Captivate can operate at 4 different frequencies.  FREQSHFT controls the desired frequency.

Hello Dennis Lehman,

The customer is investigating whether it is possible to implement both EMC countermeasures and measures to prevent interference between adjacent boards.

The documentation states that enabling EMC applies noise countermeasures using four different frequencies.

However, in a previous case (not involving a TI product), the customer experienced interference between multiple adjacent boards using the mutual capacitance method with EMC enabled.

In light of this, the customer is now exploring potential countermeasures for this situation.

Are there any settings or configurations in CapTIvate that could help address or prevent this type of board-to-board interference?

Best regards,
DDdoor

Hi DDdoor,

Is the issue a cross-coupling of mutual capacitive signals between the boards, or an issue with radiated emissions causing electrical interference. 

Can the customer share a photo or diagram showing the boards in their position when the interference occurs?

Does this interference occur only when a person touches a sensor on any of the boards, or occurs all the time?

What is the application?

Hello Dennis Lehman,

I am forwarding the customer's responses regarding your inquiries.

- Is the issue a cross-coupling of mutual capacitive signals between the boards, or an issue with radiated emissions causing electrical interference?
Customer's response: It is an issue with radiated emissions.

- Can the customer share a photo or diagram showing the boards in their position when the interference occurs?
Customer's response: They cannot share a photo or diagram.

- Does this interference occur only when a person touches a sensor on any of the boards, or does it occur all the time?
Customer's response: It occurs all the time.


Best regards,
DDdoor

Hi DDdoor,

So the customer does not currently have the Captivate EMC feature enabled, correct?  And if the PCBs are moved apart from each other is the noise  reduced?  How close are the PCBs?  Are they side by side, or coplanar to each other?  Does one PCB affect the other or do they affect each other?

Hello Dennis Lehman,

The customer plans to enable the CapTIvate EMC feature and arrange the PCBs side by side.

Are there any settings or configurations in CapTIvate, other than the CapTIvate EMC feature, that could help mitigate this type of board-to-board interference?

Would it be a good approach to proceed with triggering the connected MCUs sequentially, such as MCU1 triggering MCU2, to address interference between multiple boards?

Best regards,
DDdoor

Hi,

1. It seems that customer meet this problem not with MSP430 right?

2. Here is my suggestions:

• Software: Enable EMC function (May need to adjust the parameters according to the data logging). 
• Hardware: Add ground panels at the edge of every PCB. This can help reduce the cross talk between different MSP430.

3. Trigger the MCUs in order will absolutely help. As this can ensure the touch scarnning will not happen at the same time. But I would suggest customer to reserve this option, like using GPIO and try my suggestions first, as that will add more changes on software.

Eason

Hello Eason Zhou,

Thank you for your support.

The customer is considering how to implement countermeasures with the MSP430, based on issues encountered with previous products, which did not use MSP430.

Best regards,
DDdoor