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LMX2595: SPI communication

Cedrick
Expert 8270 points
Part Number: LMX2595
Other Parts Discussed in Thread: USB2ANY

Hi,

Good day.

Our customer has inquiry about the LMX2595 . Kindly see below.

I am trying to program the LMX2995EVL via the SPI (with an micro-controller board) to just generate any frequency, but it is not working.

I check the trams with an oscilloscope and it is correct according to the datasheet. All the register values that I tried to send to the LMX2595 are from the TICS pro software made by TI so it should be the right ones. The hardware looks also correct because I took as an example the LMX2995EVL working with the TICS Pro to check the signals sent between them.

The only thing that seems not right is that the Lock LED is off, even if the value of MUXOUT_SEL is set to 1 (lock detect). I suppose the values of my registers are not correct to obtain a lock state but they are from the TICS Pro software so it does not make sense to change them.

I hope you could help me and I wish you a pleasant day.

Can you please help us? Thank you. 

Regards,

Cedrick

  • 0
    TI__Mastermind 28960 points

    Cedrick,

    Can you please have the customer share the TCS file they used? TICS Pro can generate this file with "File -> Save" menu option.

    Regards,

    Derek Payne

  • 0
    TI__Mastermind 28960 points

    A few follow-ups while we wait:

    • Did they make sure to program registers in descending order (highest to lowest address)?
    • Did they follow the procedure as documented in datasheet section 7.5.1, including toggling the RESET bit in R0, and the second R0 write with FCAL_EN=1 from a stable configuration?
  • 0 in reply to Derek Payne
    TI__Expert 8270 points

    Hi Derek,

    Here's the file they provided. TICS_DaCosta(1).tcs

    Regards,

    Cedrick

  • 0 in reply to Cedrick
    TI__Mastermind 28960 points

    Thanks Cedrick. I don't see anything wrong with the TICS Pro file, so their original success with USB2ANY programmer wasn't a fluke.

    Please follow up and double-check that the additional programming steps like reset, FCAL_EN again, have been followed as outlined in my previous post.

    Are we sure that "the only thing that seems not right is the LD light is off" means the device has been successfully programmed? Has the customer compared the current between the TI programming case and their own controller programming, to ensure the currents are similar? Is ~7GHz coming out of the RFoutA ports?