-------- Hal Murray writes: > > [email protected] said: > > I dont know if the datasheet for the Rpi4 is available to check what the > > requirements are, but you should probably expect to need some kind of PLL > > chip to deliver a clean 54 MHz on the RPi4, locked to your external > > frequency. > > Plan B would be to avoid the 10=>54 PLL chip by reprogramming the software > that sets up the internal PLLs to run off 10 MHz rather than 54MHz. That may > not be possible. It depends on how the clocking inside the ARM chip is setup.
One of the big problems with the RPi family is that only a skeleton datasheet has been made available - because: Qualcom magic sauce recipe or similar verbiage.. I've heard a lot of gripes about precisely the clock circuits being underdocumented, but I have deliberately stayed well clear of the details. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [email protected] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
