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LDC1101EVM: LDC INT_FUNC Register Function

Manish_Thakur
Genius 5085 points
Part Number: LDC1101EVM
Other Parts Discussed in Thread: LDC1101, MSP430FR5969

Hiiyyaaa Forum experts,

I need to check threshold for RP and L so for that we need to configure 0x0A register. I have configured as 0x09. I'm not seeing my RP_HIN or L_HIN is setting 0. Please tell me something about this.

If I'm setting INTB_FUNC register which is  0x0A as 0x01 then I'm seeing my RP_HIN is 0 in RO_HIN. can't we use this INTB_FUNC register to check for RP_HIN and L_HIN. Please reply ASAP. I need to finish my work as soon as possible

  • 0
    TI__Genius 17660 points

    Hello Manish,

     

    When comparing Rp and L to their respective thresholds, the RP_HIN and L_HIN values will latch to 0 after the threshold has been exceeded. In order to reset the values after they are read, you need to write the INTB_FUNC value to 0x00. If you are interested in only when the measurement is currently above the threshold, try using the RP_HI_LON and L_HI_LON values of the STATUS register.

    The INTB_FUNC value is used to report a specific flag to the SDO pin. Writing a value of 0x09 to the pin is not valid, please see table 13 in the datasheet for the different output possibilities.

     

    Best,

  • 0 in reply to Justin Beigel
    Genius 5085 points

    HI justin,

    Please give me a brief description about RP_HI_LON and L_HI_LON and also how to use them. Please< its a request because I have tried according to my datasheet but I failed to make that work if you can explain a bit, that will work for me. Hope you understood what I tried to say.

  • 0 in reply to Justin Beigel
    Genius 5085 points

    Hi Justin,

    In INTB_FUNC (RP_HI_LON bit is always getting 0 and 1 continously). Why I'm seeing that bit is always getting low and high. Can you explain this to me. How can we avoid that for better results.

  • 0 in reply to Manish_Thakur
    TI__Genius 17660 points

    Hello Manish,

    The RP_HI_LON and L_HI_LON are outputs based on a hysteresis comparison between the RP_DATA/L_DATA and your thresholds. If you are seeing these values switch rapidly between 0 and 1, then it could be due to a few different things. It could be due to the high and low thresholds that you have set. Another thing to check is the values of the actual data (RP_DATA/L_DATA). If they are moving around a lot, it could be due to the sensor/target setup that you are using. Check out the LDC Sensor Design document for more information on the sensors. Additionally, if you are unsure of where your thresholds should be set for the Rp measurement, the Measuring Rp of an L-C Sensor for Inductive Sensing app note can help.

    Hope this helps,

  • 0 in reply to Justin Beigel
    Genius 5085 points

    Hi Justin,

    You have mentioned this "Writing a value of 0x09 to the pin is not valid, please see table 13 in the datasheet for the different output possibilities" So the attached image says

    .

    1) If you want to check RP_HI_LON then write 0x02 in INTB_FUNC register and If we want to check L_HI_LON then write 0x16 in INTB_FUNC am I correct at this point?

    2) If I want to check RP_HI_LON and L_HI_LON then can we write 0x18 in INTB_FUNC register.

    Please clear my concepts about this point then my doubts will be clear regarding the LDC1101. Please reply ASAP.

  • 0 in reply to Manish_Thakur
    TI__Genius 17660 points

    Hello Manish, 

    The INTB_FUNC register is used to determine which output will show on the SDO pin of the device. You can only have one output show up on the pin at a time so if you need to check the value of both, then you will need to access the register values through the I2C or switch which one is output to the SDO pin.  

    Hope this helps, 

  • 0 in reply to Justin Beigel
    Genius 5085 points

    Hi Justin,

    To INTB Reporting on SDO we need to write 0x80 into INTB_MODE register. am I correct here?

    one last question regarding this topic how we can get interrupt on SDO pin. I'm using MSP430FR5969 board so what I'm trying to get is I need interrupt on SDO pin if DRDY is set or clear. And in datasheet it has been said that SDO pin will go low and high as shown in image

    so my SDO pin is a port pin of GPIO if I configure that port for interrupt so there interrupt will generate or not on port pin. Please clear my this doubt and afterthat you can further move to close the thread.

  • 0 in reply to Manish_Thakur
    TI__Genius 17660 points

    Hello Manish,

    You are correct, bit 7 of the INTB_MODE register needs to be written to 1 for the reporting to happen. Then it will report in whichever mode you have set.

    For the interrupt, I cannot see the image attached but the SDO will go low when INTB is asserted. Having a GPIO attached to the SDO will work as long as your GPIO is setup for a falling edge trigger.

    Hope this helps,

  • 0 in reply to Justin Beigel
    Genius 5085 points

    Hi Justin,

    Thanks for your help. it helped me a lot. I'm able to do now. Really appreciate for your answer.