fsfw-hal/stm32h7/spi/spiDefinitions.cpp

#include "spiDefinitions.h"

void spi::assignSpiMode(SpiModes spiMode, SPI_HandleTypeDef& spiHandle) {
    switch(spiMode) {
    case(SpiModes::MODE_0): {
        spiHandle.Init.CLKPolarity = SPI_POLARITY_LOW;
        spiHandle.Init.CLKPhase = SPI_PHASE_1EDGE;
        break;
    }
    case(SpiModes::MODE_1): {
        spiHandle.Init.CLKPolarity = SPI_POLARITY_LOW;
        spiHandle.Init.CLKPhase = SPI_PHASE_2EDGE;
        break;
    }
    case(SpiModes::MODE_2): {
        spiHandle.Init.CLKPolarity = SPI_POLARITY_HIGH;
        spiHandle.Init.CLKPhase = SPI_PHASE_1EDGE;
        break;
    }
    case(SpiModes::MODE_3): {
        spiHandle.Init.CLKPolarity = SPI_POLARITY_HIGH;
        spiHandle.Init.CLKPhase = SPI_PHASE_2EDGE;
        break;
    }
    }
}

uint32_t spi::getPrescaler(uint32_t clock_src_freq, uint32_t baudrate_mbps) {
    uint32_t divisor = 0;
    uint32_t spi_clk = clock_src_freq;
    uint32_t presc = 0;
    static const uint32_t baudrate[] = {
            SPI_BAUDRATEPRESCALER_2,
            SPI_BAUDRATEPRESCALER_4,
            SPI_BAUDRATEPRESCALER_8,
            SPI_BAUDRATEPRESCALER_16,
            SPI_BAUDRATEPRESCALER_32,
            SPI_BAUDRATEPRESCALER_64,
            SPI_BAUDRATEPRESCALER_128,
            SPI_BAUDRATEPRESCALER_256,
    };

    while( spi_clk > baudrate_mbps) {
        presc = baudrate[divisor];
        if (++divisor > 7)
            break;

        spi_clk = ( spi_clk >> 1);
    }

    return presc;
}