Can I leave the Oscillator in pin when using the internal clock of STM32F0 microcontroller?

Forum|Forum|5 years ago
May 30, 2021
2 replies
2368 views

Hi, I am new to custom PCB design. I am designing my first PCB with stm32f030 and PowerSTEP01. My application involves SPI communication with PowerSTEP01. I want to use the internal clock of the STM32 MCU to avoid external oscillator and capacitors. Does SPI communication work well without external clock signal? If yes, Should I leave the clock input pins PF0 and PF1 floating or pull down to ground?

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Best answer by TDK

The internal HSI clock accuracy is good to a few percent, details in the datasheet. In general, this will not be an issue for SPI communication unless you are at the very maximum speed support by the chip you're interfacing with.

If you're not using them, it is up to you if you leave them floating or pulled to ground. Pulled to ground will use slightly less power.

TDKAnswer

Super User

The internal HSI clock accuracy is good to a few percent, details in the datasheet. In general, this will not be an issue for SPI communication unless you are at the very maximum speed support by the chip you're interfacing with.

If you're not using them, it is up to you if you leave them floating or pulled to ground. Pulled to ground will use slightly less power.

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Piranha

Principal III

If HSE is not used, one can use those pins just like other pins - configure as inputs, outputs or some alternate function, if there is such.

As for hardware recommendations, besides AN4325, also read AN4899.

RPach.1Author

Associate

Thank you for clarification.

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