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Balaraju Arror
Associate II
July 4, 2017
Solved

Bypass vs Crystal ceramic

  • July 4, 2017
  • 3 replies
  • 4970 views
Posted on July 04, 2017 at 15:47

Hello Team,

As per STM32F769I-DISCO board schematic, I understood it should be Bypass clock source.

0690X00000607RIQAY.png

But default cube project gives selection as Crystal ceramic. Why it is ceramic crystal?

0690X00000607L6QAI.png0690X00000607RSQAY.png

Request you to help me which one I should select for STM32 -DISCO board?

    This topic has been closed for replies.
    Best answer by TechGuyMike

    Since NZ2520SB is not a ''Crystal/Ceramic Resonator'', but rather a crystal oscillator, you should use "BYPASS Clock Source" as the high speed clock option in CubeIDE/CubeMx.

    3 replies

    Tesla DeLorean
    Guru
    July 4, 2017
    Posted on July 04, 2017 at 19:04

    To stop OSC_OUT banging up and down, BYPASS would generally be the desirable choice. The system is going to clock if OSC_IN delivers a pulse train meeting the input requirements.

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    TechGuyMikeBest answer
    Associate III
    August 26, 2022

    Since NZ2520SB is not a ''Crystal/Ceramic Resonator'', but rather a crystal oscillator, you should use "BYPASS Clock Source" as the high speed clock option in CubeIDE/CubeMx.

    Tesla DeLorean
    Guru
    August 26, 2022

    Correct

    BYPASS should have different input characteristics, and also not output a signal on OSC-OUT

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