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How to change clock settings in Cerberus


#1

Dear all, today is arrived our first pack of custom board based on Cerberus but a terrible mistake was made…
Our protype was tested and ok, so we have started the production but a mistake in the bill of material has caused the mounting of the wrong quartz oscillator.

Now we have 100 boards with a 25MHz quartz.
Is possible to recompile the firmware for using that frequency as base base clock instead of 12MHz? If yes, what should I change? In which files?

Thanks


#2

@ Cybernox - I believe you will have to change the setting and build your own firmware. Look at this thread for recompiling the Cerb firmware: http://www.ghielectronics.com/community/forum/topic?id=10015

For the clock crystal settings, the Discovery and Cerberus had different crystals, so you can look to this blog post for how to do that:
http://mc2.unl.edu/2013/01/29/fez-cerberus-firmware-image-compiled-for-stm32f4-discovery/

But, what I don’t know is if the faster crystal will make the chip run faster and hotter. You may need to have a divide by 2 operation in there somewhere to slow it back down… You should look at the spec sheet for the STM32F405 chip to see.

-Valkyrie-MT