STM32F303CCT6 - SPI1 Prescaler Issue (Can't Set to 2)

[Shreayas_Acharaya]

Hi everyone,

I'm working with the STM32F303CCT6 chip, and I've configured the system clock such that HCLK is running at 72 MHz.

I'm trying to configure SPI1 in full-duplex master mode using CubeMX / STM32CubeIDE. However, when I attempt to set the prescaler to 2, it gives me the following warning:

"With this Prescaler value and APB2 Clock Frequency (72.0 MHz), Baud Rate is more than 18.0 MBits/s.
Please set Prescaler more than 4."

This is confusing because I thought SPI1 could go up to 32 Mbit/s.

Has anyone encountered this?

• Is this a limitation from CubeMX or HAL?

• Is it safe to ignore this warning and proceed manually in code?

• Or is there a hardware limitation I'm overlooking?

Any insights or workarounds would be greatly appreciated!

Thanks in advance!

[KDJEM.1]

Hello @Shreayas_Acharaya;

 

As mentioned in the datasheet DS9118 Rev 14 Section 3.22 Serial peripheral interface (SPI)/Inter-integrated sound interfaces (I2S) the SPIs are able to communicate up to 18Mbits/s: "three SPIs are able to communicate up to 18 Mbits/s in slave and master modes in full-duplex and half-duplex communication modes" 

 

Thank you.

Kaouthar