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LMX2582: Initial Programming Sequence

Tucker Bayler
Prodigy 30 points
Part Number: LMX2582

Hello, 

In the TICS software, the description of Register 0 (specifically the Reset pin) says that when the device is reset, the registers are programmed to default values.  I've read on other threads that it is required to program ALL registers on the initial programming sequence.

1.) Is this true? 

2) If some registers are only going to be programmed to the default values (and reset "Resets" to the default values) why do I then need to re-program all of the registers?  

assuming the answer to question 1 is true:  is it required to program the registers in reverse order?  R64-R0.

Thanks!

Tucker

  • 0
    TI__Genius 11900 points

    Hello Tucker,

    The default values, are not necessarily the values you require. Programming all registers after power-up helps ensure that you have the right settings.

    It is important to program the registers in reverse order so the VCO and PLL are setup correctly and to end with writing R0[3] = 1 to calibrate frequency at the end.

    Thanks,

    Vibhu

  • 0 in reply to Vibhu Vanjari
    Prodigy 30 points

    Thanks for the reply.  

    I am still curious though, do I HAVE to program all the registers?  Or, if I'm wanting to use the default values on certain registers, can I omit them from the initial programming sequence?  I do realize that I can just program them all and be done with it, but I'm just wondering what is specifically required. 

    thanks, 

    Tucker

  • 0 in reply to Tucker Bayler
    TI__Genius 11900 points

    Hello Tucker,

    You do not HAVE to program them all. I would still recommend following the datasheet on this. Soft reset the device after power up and program R0 last.

    Thanks,

    Vibhu

  • 0 in reply to Vibhu Vanjari
    Prodigy 30 points

    Vibhu,

    I'll go ahead and program them all.  I guess to me, the data sheet is necessarily clear in letting a user know that all registers need to be programmed.  And logically, to me at least, if I want a register to be in the default state, I shouldn't have to re-program said register after reset.  

    Anyway, thanks for the clarification and feedback.  I appreciate it. 

    Tucker