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LMP90080-Q1: Values won't update

Levi De Leus
Prodigy 10 points
Part Number: LMP90080-Q1

Tool/software:

Hi all,

We are going use the LMP90080-Q1 to convert PT1000 resistance to measured temperature. 

After testing the ADC in combination with a potentiometer the data won't update anymore...

I use the following settings : 

  • LMP90080Register.RESETCN, 0xC3   
  • LMP90080Register.GPIO_DIRCN, 0x01  (Is used for debug LED)
  • LMP90080Register.GPIO_DAT, 0x01 
  • LMP90080Register.CH0_CONFIG, 0x05  (Set gain to 4, ODR to 16775)
  • LMP90080Register.CH_SCAN, 0x00  (Set to Single channel continuous scan)
  • LMP90080Register.ADC_AUXCN, 0x23   (IB1 = 300uA and internal clock)
  • LMP90080Register.ADC_RESTART, 0x01

After these settings I do a read of LMP90080Register.ADC_DONE but there are no new conversions available...
Is there someone who could help me out, this used to work in the past and now i see the behaviour on all of the dev boards. 


  • 0
    TI__Mastermind 41491 points

    Hi Levi De Leus,

    You said:

    Levi De Leus said:
    Is there someone who could help me out, this used to work in the past and now i see the behaviour on all of the dev boards. 

    Can you explain this in more detail? The boards (and code I presume) used to work, and now they don't? Has anything changed between then and now?

    If you just power up the device and start conversions (without writing to any of the registers you show in your post), do you get data?

    If you enable the dedicated DRDY pin (shared with GPIO6) and probe that, do you see that pin toggling after starting conversions?

    Are you able to still read and write to registers correctly?

    -Bryan

  • 0 in reply to Bryan Lizon86
    Prodigy 10 points

    Hi Bryan, 

    After some testing it seems the current sources won't enable.. 
    When connecting a external current source to the circuit i was able to measure new values. 

    Did someone have the same issue? 


    Yes i can still read and write the registers. 
    I test this with a LED that is enabled with setting the D0 as output and toggling the output between HIGH en LOW. 

  • 0 in reply to Levi De Leus
    TI__Mastermind 41491 points

    Hi Levi De Leus,

    I replicated your settings on my EVM, and I do not see any issues. I was able to get the IDACs to output and read back the voltage across a resistor

    Can you provide logic analyzer plots of your digital communication so we can review?

    -Bryan