|best| Download Spi.h -

Download the STM32Cube firmware package for your MCU series directly from ST’s website. The SPI header will reside in Drivers/STM32F4xx_HAL_Driver/Inc/stm32f4xx_hal_spi.h .

#include <plib/spi.h>

If you are missing the file or seeing a "File not found" error, follow these steps instead of looking for a standalone download: download spi.h

Serial.println("SD card initialized successfully."); Download the STM32Cube firmware package for your MCU

The protocol is very robust and has been a industry standard for decades. ❌ download spi.h