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LMK03318: How to set REFSEL pin for hard-mode ROM Option 45 using 25MHz crystal

Part Number: LMK03318

Hello,

I am working on a brand new design for the TMS320C6678ACYP DSP. Pursuant to a suggestion in an earlier e2e dialogue, I have chosen to use the LMK03318 Clock Generator to provide the clocks for the DSP. It turns out that ROM Option 45 will do everything I need: 100MHz for the CORECLK on Output 0, 100MHz for the DDRCLK on Output 2, and 250MHz on Output 4 for the SRIOSGMIICLK. I have the HW_SW_CTRL pin of the LMK03318 tied to 3.3V to select hard pin mode. The GPIO pins are set to select ROM Option 45.

I’m only using the 25MHz crystal connected to the SECREF_P and SECREF_N pins and have no other clock sources. I have the PRIREF_P and PRIREF_N pins floating (no connection). I see on page 66 of the datasheet that the second column (PLL IN MUX) indicates that the REFSEL pin is used to select the input clock source. Then I referred to Table 3 on datasheet page 33. This table tells me that for the situations where the REFSEL pin is relevant, that REFSEL should be set to Vim to use the secondary PLL reference.

Is it correct that I should set the REFSEL pin to the Vim voltage level so that the 25MHz crystal connected to the SECREF_P and SECREF_N pins is used as the input clock source? Or have I somehow misinterpreted something?

Regards,
Larry