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I plan to connect Arduino UNO via I2C / UART with a controller based on STM32F334K8T6, whose frequency will be about 20mHz or higher.

Tell me, does the difference in clock frequencies of microcontrollers affect the operation of buses between them?

The tire speed will be equal. (UART 115200 Baud / I2C 100kHz)

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    20 millihertz? I guess you mean megahertz, or MHz, with a capital M. Nov 24 '19 at 19:08
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Tell me, does the difference in clock frequencies of microcontrollers affect the operation of buses between them?

No it doesn't. Or not much any way. It may affect the accuracy of clock generation1, which may have an affect at very high asynchronous baud rates, but other than that, no.

For synchronous communication it's all synchronised to the communication protocol's clock, so processor clocks are irrelevant.


1: Baud rates are usually generated as an integer division of the system clock. Different system clocks give different results for baud rate divisor calculations, yielding marginally different baud rates. Different baud rates will have different error percentages on different system clocks. At low speeds this has no noticeable affect. At high speeds (millions of bits per second) it can cause errors to creep in.

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  • Majenko, thank you for the answer!
    – Delta
    Nov 24 '19 at 14:37
  • Nice thorough answer. <voted> You provided a simple yes/no answer, and then added some more nuance without obscuring the top level "doesn't matter" nature of the answer. Well done. (As usual.)
    – Duncan C
    Nov 24 '19 at 15:53

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