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Visitor II
May 27, 2024
Question

Internal pull down value and suggested pull up for i2C

  • May 27, 2024
  • 1 reply
  • 728 views

Hi i am using STM32U585 to interface with fuel gauge using i2c. I want to know the internal pull down of ST MCU and if needed what should be the external pull-up resistance value.

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    1 reply

    Graduate II
    May 27, 2024

    I2C doesn't use a pull-down, it's an Open-Collector / Open-Drain type situation, the transistor switches to Ground

    Pull up-down internally is around 40K, depending on how aggressive a rising edge you want, perhaps 2K7 externally

    https://www.st.com/resource/en/datasheet/stm32u585zi.pdf