[SOLVED] Scaling down the SPI0 clock value on RPi 3B+/4B

[dhmilton3]

I have a custom STM32 MCU board that interfaces with an RPi 3B+ via the SPI protocol. The MCU (STM32F407) has its SPI peripheral clock set at 84MHz and is configured as a slave device. For reliable transmission, the Master (in this case, the RPi) needs to have its SPI clock at 1/2 value i.e, at 24MHz or lower (I read that it needs to be an even number). From what I understand the RPi's SPI clock runs at 250MHz. How can I scale down this clock value?

 

[KlausST]

HI,

half of 84MHz is 42MHz. .. but yes, 24MHz and lower should be O.K.

I´m sure 250MHz is not the standard SPI clock frequency. Maybe the maximum.
And I´m sure one can adjust SPI clock frequency.

But for detailed help you need to tell which IDE, language, libriaries and so on... you use...

Klaus

 

[00kam]

hello
see this link maybe helpful

Raspberry Pi 3 B+ - DEV-14643 - SparkFun Electronics

The Raspberry Pi 3 B+ is here to provide you with the same Pi as before, but now with gigabit and PoE capable Ethernet!

www.sparkfun.com

kamal