STM32 chips with 180Mhz and USB is impossible?

This is disappointing but the team just pointed out that the STM32 chip can not run 180Mhz and also run USB, which needs 48Mhz. Anyone have looked into this and can confirm one way or another?

Please post your values for


from the system_stm32xxx.c file

You may not get the 48Mhz with 180Mhz :wink:

but you might get away by using 192Mhz :slight_smile:

@ Rajesh -

360>= PLL_N <= 432.
SystemCoreClock is what we want 180mhz
PLL_Q is what we are looking.


PLL_N 384

SystemCoreClock 192000000

@ Gus maybe a good opportunity for GHI to add CPU clock scaling as a proprietary feature.

I looked at the G80 dev board schematic, looks like the HSE crystal is 12Mhz ? Can you swap that with a 16Mhz one for testing ?

@ Rajesh -

Problem is not crystal, there is no number in range 192-432 that can be divisible by 48 and 180.

With HSE as 16Mhz

SystemCoreClock = ((HSE_VALUE / PLL_M) * PLL_N) / PLL_P;

PLL_M : 8
PLL_N : 360
PLL_P : 4
PLL_Q : 15

CoreClock can be 180Mhz



will be 48Mhz

With 12Mhz

PLL_M : 6
PLL_N : 360
PLL_P : 4
PLL_Q : 15

will give core clock as 180Mhz and USB as 48Mhz


Ok, I emailed Gus the XLS that I was using, let me know.

This is what we are looking for. Thank you too much!


@ Rajesh - you deserve a gift for putting a huge smile on Dat’s face;)

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Awesome ! more important, the G80 will be running at full steam :slight_smile:

I vote for getting @ Rajesh an G80 dev board, so he can check if you did it right :wink:


Absolutely. I already said there is a gift and what a better gift than that :slight_smile:

The g400 runs at 400mhz
The g120 runs at 120mhz
why isn’t this the g180?

@ mtylerjr - GHI has changed the nomenclature, the numbers don’t mean the clock speed anymore, it is more of a weighted average of the features and capacity.

If the G80 was named G180, then it may make the G120 seem lower, when the G120 has more memory, IO, Native Graphics, etc. etc. The G80 may run faster as it runs from RAM/ROM that is on the die rather than the bus memory on the G120 but the G80 may not be able to provide the same experience for a GUI (HMI) application.

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You are just trying to mess with the OCD people. …admit it :slight_smile:

And for the next decade, 50% of the public GHI support will be dedicated to answer this question… Again, and again…