spi_bitbang.c

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#include <cpu/irq.h>
#include <cfg/module.h>
#include "spi_bitbang.h"
#include "hw_spi.h"

void spi_assertSS(void)
{
    ATOMIC(SS_ACTIVE());
}

void spi_deassertSS(void)
{
    ATOMIC(SS_INACTIVE());
}

uint8_t spi_sendRecv(uint8_t c)
{
    uint8_t data = 0;
    uint8_t shift = SPI_DATAORDER_START;


    ATOMIC(
        for (int i = 0; i < 8; i++)
        {
            /* Shift the i-th bit to MOSI */
            if (c & shift)
                MOSI_HIGH();
            else
                MOSI_LOW();
            /* Assert clock */
            SCK_ACTIVE();
            data |= IS_MISO_HIGH() ? shift : 0;
            /* De-assert clock */
            SCK_INACTIVE();
            SPI_DATAORDER_SHIFT(shift);
        }
    );
    return data;
}

MOD_DEFINE(spi);
void spi_init(void)
{
    ATOMIC(SPI_HW_INIT());
    MOD_INIT(spi);
}

void spi_read(void *_buff, size_t len)
{
    uint8_t *buff = (uint8_t *)_buff;

    while (len--)
        /* Read byte from spi and put it in buffer. */
        *buff++ = spi_sendRecv(0);

}

void spi_write(const void *_buff, size_t len)
{
    const uint8_t *buff = (const uint8_t *)_buff;

    while (len--)
        /* Write byte pointed at by *buff to spi */
        spi_sendRecv(*buff++);

}