This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

MSP430FR6820: BOR detect function characteristics and configuration

Part Number: MSP430FR6820

MSP430 Friends & Family,

Our customer is asking the following of the FR6820 BOR detect function:

From the TI datasheet, if RST pin voltage is lower than 1.66V and the duration is longer than 2usec, we believe it would trigger the BOR, correct?

-> This appears to be the case.

And if we capture the below pulse signal on the RST pin but VDD is normally 3.3V, could Firmware add a debounce time to filter this short pulse to avoid an MCU reset?

--> some FW control is indeed supported but perhaps not for this level of pulse/noise reduction

Or is just the BOR hardware reset and as long as BOR occurs, it would reset the MCU immediately while Firmware cannot control it?

--> Again while some FW control is indeed supported perhaps not to this level 

 And also from the TI datasheet, the MCU integrates the internal digital filter to suppress short pulses - so does firmware configure this filter parameter such as pulse duration?  Or it is only a default configuration and not configurable? If it is default, what’s the default setting?

--> Need MSP team to comment further please as DS is not explicit on this 

 Thanks for any input you can provide!

Regards,

Chris (for customer)

  • Hi Chris,

    From the TI datasheet, if RST pin voltage is lower than 1.66V and the duration is longer than 2usec, we believe it would trigger the BOR, correct?

    I think 1.66V is not the explanation for RST pin, it describes the min voltage of VCC rather than RST. The low signal of RST should refer to digital input voltage as below, it's the  best set the voltage lower than 0.75V.

    And if we capture the below pulse signal on the RST pin but VDD is normally 3.3V, could Firmware add a debounce time to filter this short pulse to avoid an MCU reset?

    I think it supports debounce time in RST pin, as long as it covered VIT- voltage range, I suggest you can take 1.35V as low input for the margin concerned.

    Or is just the BOR hardware reset and as long as BOR occurs,

    It described that min time of external reset pulse duration on RST is 2us. So it should not immediately reset, have you confirm the case of it?

    so does firmware configure this filter parameter such as pulse duration?  Or it is only a default configuration and not configurable? If it is default, what’s the default setting?

    It is a default configuration, and it describes that "the minimum reset pulse duration is specified in the device data sheet", as shown in DS, and it is 2 us.

    I hope this can resolve the issue, kindly reply to me if there is any feedback.

    Best Regards

    Sal

**Attention** This is a public forum