AnsweredAssumed Answered

clk frequency output problem

Question asked by Mohamed GORRAB on Apr 13, 2018
Latest reply on Apr 23, 2018 by Nawres GHARBI

Hi,

 
I use the STM32CubeMX to send data using UART, but I have a clock frequency problem,
I configured the clk as shown on the picture below
1
logically, I should obtain 80MHZ as an outpout frequency, but when I use the scope, it is fixed all of the time at 16 MHZ if I use MSI or HSE as shown on the picture below
2
and it is fixed at 32 MHZ if I use the HSI,
 3
I tried to use the different divisions /1, /8.. and the different clk (PPLCK, SYCLK, HSE...) to obtain the correct frequency, but everytime, I have the same frequency output that I showed on the scope,
The same problem, if I use the HAL_RCC_GetSysClockFreq() instruction, It gives 16 MHz and 32MHz values, we can't reach the 80MHz!!
below the code, 
tmtrack.dll?AttachmentPage&AttachmentID=50529
We need to understand this contradiction to advance, because we use the baudrate variable in our project, and the baudrate depends on the frequency value!
Thanks in advance,
 
Mohamed 

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