Hello everyone,
I'm seeking some clarification regarding the peripheral and the oscillator clock frequencies fed to the canFD module. Is my understanding correct that the peripheral clock is the CAN_CLK_ROOT in CMM that can be muxed and divided to have different frequencies, while the oscillator clock is the static 24MHz clock from the crystal oscillator? If so, does that mean that the duration of 1 time quanta is fixed to 41.67 ns which is what goes into the bit timing calculations? This doesn't seem right to me so I'd appreciate it if anyone can correct my confusion. I see that some of the equations in the RM involve both of these clocks.
Thank you,
Lam
Hi again @mayliu1 ,
so if fSYS is the system clock frequency, would it be AHB_CLK_ROOT, which is 420Mhz in my case?
if so, is it involved in the calculation of the time quanta? I don't suppose so but the language, particularly the use of the words oscillator and peripheral, is a little bit confusing to me. I initially did think that the time quanta was directly derived from just the flexCAN clock.
Best Regards,
Lam
Hi @LamK ,
Thank you so much for your interest in our products and for using our community.
In IMXRT1060RM, it describe as below shown.
fCANCLK is the Protocol Engine (PE) Clock , it can be configured via CAN_CLK_ROOT.
fSYS is the frequency of operation of the system clock.
For more detail information about Clock, I suggest you can check Clocks in Config Tools .
Best Regards
MayLiu
Hi @LamK ,
Thanks for your updated information.
Regarding your question: so if fSYS is the system clock frequency, would it be AHB_CLK_ROOT, which is 420Mhz in my case?
I do not think so. Please check the IMXRT1060RM.
Best Regards
MayLiu
Ok thank you @mayliu1, I could have found that information about the clocks in the Clock Consumers tab, looks pretty useful. Ultimately I was concerned that the fSYS could be involved in the calculation of time quanta when I saw the equation NumClkBit which made me equate peripheral clocks with time quanta, which wasn't the case and was where my confusion come from.
Thank you for your help again.
Best Regards,
Lam
You are welcome.