Unable to Achieve 5 MHz SPI Clock on STM32G474RE (Max Reaching 3 MHz)

[RoshiniBejawada]

Hello,

I am implementing SPI master communication on an STM32G474RE, transferring 68 bytes per transaction. However, I am unable to achieve the desired SPI clock speed of 5 MHz—currently the SPI clock only reaches approximately 3 MHz.

The system clock is configured at 160 MHz, and I have tested the peripheral clock (PCLK) at both 80 MHz and 160 MHz. Based on these clock settings, I tried multiple SPI prescaler values (16 and 32) to obtain a 5 MHz SCK frequency. In addition, the SPI_SCK pin is configured in High-Speed mode. Despite these settings, the SPI output clock still does not exceed approximately 3 MHz.

Has anyone experienced similar limitations, or is there an additional configuration step required to achieve a stable 5 MHz SPI SCK on the STM32G474RE? Any guidance or suggestions would be greatly appreciated.
Thanks in advance.

[ELABI.1]

Hi @RoshiniBejawada,

can you please give me more details about your project so that I can produce your use case? For example, which SPI mode are you using? How did you measure the SPI frequency?

Thanks.

ELABI.1

[Andrew Neil]

Welcome to the forum.

Please give more details of your setup - see: How to write your question to maximize your chances to find a solution

 

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@RoshiniBejawada wrote:

Despite these settings, the SPI output clock still does not exceed approximately 3 MHz.

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How did you determine that?

What settings, exactly, did you use?