MSP430FR2676: Using internal reference capacitors

Koichiro Tashiro

Part Number: MSP430FR2676

Hi,

My customer wants to convert capacitance delta into conversion count.
He found similar question is below E2E.
https://e2e.ti.com/support/microcontrollers/msp-low-power-microcontrollers-group/msp430/f/msp-low-power-microcontroller-forum/802439/msp430fr2633-conversion-of-capacitance-into-counts/2978748?tisearch=e2e-sitesearch&keymatch=conversion%25252520count#2978748

In that thread, internal reference capacitors are used for such purpose and sample code was also provided.
It seems it worked fine for FR2633.

Question)
The same approach can be taken for FR2676 as well?
Is there any point customer needs to take care?

Thanks and regards,
Koichiro Tashiro

over 4 years ago

0 Eason Zhou over 4 years ago

TI__Mastermind 39875 points

Yes, they can. It is the same way to apply refer cap from GEN1(FR2633) to GEN2(FR2676).

0 Koichiro Tashiro over 4 years ago in reply to Eason Zhou

TI__Mastermind 22945 points

Eason,

Customer wants to check if CAPx,y pin is open or sensor is properly connected to the pin by software.
By using the same approach, customer thinks they can tell the pin is open or not.
i.e. if the pin is connected to valid sensor, the baseline capacitance should be around some known value.
if the baseline capacitance is low, the pin is considered as open.

Is this valid? Or do you have any concerns to use this method?

Thanks and regards,
Koichiro Tashiro

+1 Eason Zhou over 4 years ago in reply to Koichiro Tashiro

TI__Mastermind 39875 points

It is valid. But you first need to know what the value is when the pin is open.

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MSP430FR2676: Using internal reference capacitors