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JGree.111
Associate
January 25, 2019
Solved

STM32F105RBT6 systick slower than expected

  • January 25, 2019
  • 2 replies
  • 1911 views

0690X000006DEUHQA4.jpgI write a delay function using systick,it works well in stm32f103rbt6,but the same function does not works well when I select another chip stm32f105rbt6.when I toggle the led every 500ms,it is actually toggled every 1562ms,much slower than expected when I measured the delayed time using the oscilloscope.I have checked the 8M Crystal/Ceramic resonators and found it works well.Please help me find the problem,thank you very much!

compiler:ARM MDK 5.15

LED PIN:PD2

RCC:8M Crystal/Ceramic resonators

This topic has been closed for replies.
Best answer by JGree.111

Thank you very much,I've just solved this problem,the reason is that the standard library code take the Crystal/Ceramic resonator to be 25M as default,but actually,I used an 8M Crystal/Ceramic resonator,so I must modify the standard library to adapt this change.

anyway,thanks for your help!

2 replies

Tesla DeLorean
Guru
January 25, 2019

Make sure HSE_VALUE (define) is 8000000 and not 25000000

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JGree.111
JGree.111AuthorBest answer
Associate
January 25, 2019

Thank you very much,I've just solved this problem,the reason is that the standard library code take the Crystal/Ceramic resonator to be 25M as default,but actually,I used an 8M Crystal/Ceramic resonator,so I must modify the standard library to adapt this change.

anyway,thanks for your help!

JGree.111
JGree.111Author
Associate
January 25, 2019

I've just solved this problem,the reason is that the standard library code take the Crystal/Ceramic resonator to be 25M as default,but actually,I used an 8M Crystal/Ceramic resonator,so I must modify the standard library to adapt this change.