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Original question:

CDCE62002: pll is not locking.

CDCE62002: EVM Software input reference buffer select does not match data sheet

Jerry Ethridge
Prodigy 25 points
Part Number: CDCE62002

In the EVM, choosing LVDS input buffer, sets INBUFSELX = 1, and INBUFSELY = 0. The data sheet indicates that in order to select LVDS on the input, it should be (X,Y) = (01).

Either the EVM is in error or the data sheet. Which one is correct? I am leaning towards the data sheet being correct because there is a note in the Revision history that bits 0 and 1 were corrected.

Also, it is very confusing when some parameters in the data sheet are listed with LSB to the right and others are listed MSB to the right. All the input and output buffer select bits are listed MSB to the right, as are the smart mux bits, all other parameters are LSB to the right as shown in the Tables. 

There are many bits in register two that are listed as reserved or for TI use only. However, the data sheet does not indicate what should be written to these bits when writing to register two. I have been setting those bits to zero, is this correct?

One last comment. The EVM software has a button for EEPROM Write, and another for EEPROM Write + Lock. The data sheet shows in the revision history that references to EEPROM Locking has been removed. Is this feature no longer available? In any case, I have not been able to get the EEPROM feature to work at all, which is not a big deal because I do not need.

Thanks

Jerry Ethridge

Sr Hardware Engineer

AMX by Harman - Dallas

3000 Research Drive

Richardson, TX  75082

Phone: 469.624.7611

  • 0
    TI__Mastermind 18070 points

    Hi Jerry,

    I'm looking into this and will get back to you soon.

    Regards,

    Hao

  • 0 in reply to Hao Z
    TI__Mastermind 18070 points

    Jerry,

    I checked the previous version of datasheet and the LVDS and LVPECL were indeed swapped from rev D to revE. I also found an internal document explaining that the previous codes for LVDS and LVPECL were incorrect. So you are right, the current datasheet is correct.

    For reserved bits, please use the default settings in the software. Go to File -> Save as, then check the register setting from the saved file. Last four bits are address bits and the first 28 bits are data bits, MSB first. Refer to Figure 35 for details.

    Yes please follow the datasheet and do not use the features removed by recent datasheet revisions.

    Regards,

    Hao