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LMP90080, LMP90100 and DRDYB signal

Nicola
Intellectual 345 points
Other Parts Discussed in Thread: LMP90080, LMP90100, LMP90079

Dear Sirs,

I'm beginning to develop an application using LMP90080.

I noticed that the DRDYB signal behavior seems different from LMP90080 (see figure 20 on chapter 16.5.6), where it doesn't deassert after ADC data read, and LMP90100 (same figure and chapter numbers, but different data-sheet), where it deasserts just after ADC data read.

Is there really a difference between the DRDYB management of the two chips?

Thanks

  • 0
    TI__Guru**** 168895 points

    Hi Nicola,

    We've got some folks looking into this LMP90080 query for you and we'll respond as soon as possible.

  • 0
    TI__Intellectual 2065 points

    Hi Nicola,

    Nice to here from you. 

    Your observation is perfectly right. LMP90080 is a 16-bit device and LMP90100 is a 24-bit device. You will be reading only 2 bytes of data from LMP90080. Hence there is a difference between the DRDYB behavior. But if you use the falling edge of the DRDYB as the interrupt, you wont find difference between the two from the mcu perspective. 

    Hope this helps you. I am interested to know your application and are you looking to use both LMP90100 and LMP90080 ?

    Regards
    Murali 

  • 0 in reply to MS1291
    Intellectual 345 points

    Dear Murali,

    Thank you for your reply.

    So if on LMP90080 I manage to read also the reserved location at 0x1C together with the two registers at address 0x1A and 0x1B, should I expect to see the DRDYB deasserting like LMP90100?

    Regarding my application, I plan to use an LMP90079 to read two RTDs, plus some other voltage measurements. I don't plan to use an LMP90100, I was looking at its documentation only because I didn't found any application note for LMP900xx...

    Thank you

  • 0 in reply to Nicola
    TI__Intellectual 2065 points

    Hi Nicola,

    Yes, you will see DRDYB deasserting like LMP90100 when you read the reserved location 0x1C.

    Regards,
    Murali 

  • 0 in reply to MS1291
    Intellectual 345 points

    Dear Murali,

    Ok, thank you for your help.

    Regards,

    Nicola