Hello,
I have an eval board with a LMK04826B on it. I would like to use a common signal for both locking PLL1 and sysref as discussed here:
https://e2e.ti.com/support/clocks/f/48/t/424453
I am running VCO1 at 2500 MHz locking a 100 MHz VCXO to an external tone (several megaherz) reference on CLKin1. I would like to use the same reference - split - for sysref on CLKin0. My problem is with register 0x139. If I use the VCO for sysref it is no problem:
SYSREF_CLKin0_MUX = 0
SYSREF_MUX = 3 (continous)
If I try and switch to the external reference:
SYSREF_CLKin0_MUX = 1
SYSREF_MUX = shouldn't matter - but I've tried 0, 1, 2, 3
I get absolutely no output. I can verify signal is present on CLKin0 by switching the PLL1 mux over to CLKin0 and showing lock but for the testing shown here:
reg 0x147 is set to 0x18:
CLKin_SEL_POL = 0
CLKin_SEL_MODE = 1 (cLKin1 Manual)
CLKin1_OUT_MUX = 2 (PLL1)
CLKin0_OUT_MUX = 0 (SYSREF Mux)
Thanks for any info anyone can provide.
