Hi Guys, I wanted to change clk to 25 MHz from crystal. Can the caravel take sine wave from this part? I assume the current one is cmos based square pulse of 10 MHz @Matt Venn @Tim Edwards on the board.This is for my new board

I've had success clocking caravel with an external 25 MHz clock source, both square wave and sine wave, including one with a Pierce oscillator using a discrete crystal. I don't recognize the part from the photo, but if it's an integrated part with a clock output pin you should be fine. If it's a discrete crystal, you can't interface it with the current version of caravel directly but you can add it with an external oscillator circuit.

Yes I know, I want to clock till 250MHz 😂

The ring oscillator in the caravel PLL is supposed to go up to 214 MHz at nominal corner. You might get 250 MHz out of it with the right PVT combination, but it's a stretch.

U mean DLL, right?

It's an all-digital frequency locked loop that's called PLL in the caravel sources but actually isn't one.

@htamas: The DLL was originally designed to around 200MHz but the placement was done with the digital synthesis tools and not hand-optimized, so that cut the maximum rate down significantly, to about 120MHz. You can bump that up to about 150MHz by raising the vccd voltage from 1.8V to 2.0V.