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STM32F407 > STM32F427 MIGRATION

jean_prieur
Associate III
Posted on July 08, 2014 at 17:39

Hi everybody!

I want to migrate from STM32F407 to STM32F427, and use the full power of this microprocessor (180MHz instead of 168MHz), because I need more speed ressources.

First, I find this new application note:

http://www.st.com/web/en/resource/technical/document/application_note/DM00123028.pdf

Do you know what is the frequency overdrive mode ?

Secondly, I want to set the new maximum frequency on my project (I already use a STM32F427 but at lower frequency). I use an external oscillator of 8MHz.

I use this clock parameters for the moment:

SystemCoreClock = 168000000;

 

PLL_M  = 8

 

PLL_N  = 336

 

PLL_P  = 2

 

PLL_Q  = 7

 

AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};

 

HSE_VALUE = 8000000

 

Can I only change the parameter 

SystemCoreClock

to

180000000

? Because it works but I don't know if the speed of core change.

Thank you very much!

20 REPLIES 20
pb
Associate
Posted on August 20, 2014 at 01:20

 Hmmm... Tested running an F437 part at 180MHz with PLL_Q=7, so USB clock is at 51.4286MHz. Tried this on 3 different PCs (with USB2 and USB3 chipsets), and it seems to be running OK so far? I'm puzzled. USB at 45MHz (PLL_Q=8 @ 180MHz) definitely does not work in my setup.