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LMK04828: LMK04828: Programming and clock output issue

Nikhil k
Intellectual 405 points

Part Number: LMK04828

Dear Team,

We are using LMK04828 in our custom design, currently spi programming to IC is not working however as per datasheet clock provided in OSCIN pin should be output on OSCout without any programming, correct me if i am wrong, only required condition is ic should be out of reset and all the powers should be enabled.

In our case reset is always low and all the input power and input clock in OSCIN is proper, but there is no sign of any clock on OSCOUT pin.

Kindly guide us debugging this issue 

Regards,
Nikhil K

  • 0
    TI__Genius 17901 points

    Hi Nikhil,

    You have to begin the programming sequence by writing 0x000 to 0x0008 (or 0x0009 if you are using 4-wire SPI. Can you confirm is that is the case?). The RESET condition will be cleared automatically.

    Can you provide your register configuration file?

    Thanks,

    Michael 

  • 0 in reply to Michael Srinivasan
    Intellectual 405 points

    Dear Michael,

    Thanks for the reply.

    There seems to be a misunderstanding. At this stage, we are not attempting to program the IC via the SPI bus.

    My question is about the default behavior of the device without any SPI configuration:

    Should the OSCIN clock propagate to the OSCOUT pin when the device is powered up but not programmed?

    In this unprogrammed state, is the RESET pin expected to remain asserted, or should it be released automatically?

    At present, even without SPI programming, we do not observe the OSCIN signal at OSCOUT.

    Regarding SPI (for later stages), we are using 4-wire SPI mode, and I have attached the register configuration file that we intend to use once SPI programming is enabled.

    Please let me know if my understanding of the default power-up behavior is incorrect.


    0x000090, 0x000010, 0x000200, 0x000306, 0x0004D0, 0x00055B, 0x000600,
    0x000C51, 0x000D04, 0x010005, 0x010155, 0x010255, 0x010301, 0x010422,
    0x010500, 0x010670, 0x010711, 0x010808, 0x010955, 0x010A55, 0x010B00,
    0x010C22, 0x010D00, 0x010EF8, 0x010F30, 0x011005, 0x011155, 0x011255,
    0x011301, 0x011422, 0x011500, 0x011678, 0x011711, 0x01180A, 0x011955,
    0x011A55, 0x011B01, 0x011C22, 0x011D00, 0x011E70, 0x011F11, 0x012008,
    0x012155, 0x012255, 0x012301, 0x012422, 0x012500, 0x012678, 0x012700,
    0x012808, 0x012955, 0x012A55, 0x012B00, 0x012C22, 0x012D00, 0x012EF8,
    0x012F10, 0x013008, 0x013155, 0x013255, 0x013301, 0x013422, 0x013500,
    0x013678, 0x013711, 0x013800, 0x013903, 0x013A00, 0x013B14, 0x013C00,
    0x013D01, 0x013E03, 0x013F09, 0x014009, 0x014100, 0x014200, 0x014311,
    0x0144DD, 0x01457F, 0x014611, 0x01471A, 0x014806, 0x014906, 0x014A06,
    0x014B36, 0x014C00, 0x014D00, 0x014EC0, 0x014F7F, 0x015013, 0x015102,
    0x015200, 0x015300, 0x015401, 0x015500, 0x015601, 0x015703, 0x0158C0,
    0x015900, 0x015A19, 0x015BDA, 0x015C20, 0x015D00, 0x015E00, 0x015F3B,
    0x016000, 0x016110, 0x016244, 0x016300, 0x016400, 0x0165A0, 0x0171AA,
    0x017202, 0x017C15, 0x017D33, 0x016600, 0x016700, 0x01687D, 0x016959,
    0x016A20, 0x016B00, 0x016C00, 0x016D00, 0x016E1B, 0x017300, 0x018200,
    0x018300, 0x018400, 0x018500, 0x018800, 0x018900, 0x018A00, 0x018B00,
    0x1FFD00, 0x1FFE00, 0x1FFF53,

    Regards,
    Nikhil K

  • 0 in reply to Nikhil k
    TI__Genius 17901 points

    Hi Nikhil,

    The default settings should allow the clock provided to the OSCin pin to be buffered out of OSCout. 

    Can you probe before the OSCin pin to ensure you are seeing a signal coming in?

    Thanks,

    Michael