SdSpiAvr.h

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#ifndef SdSpiAvr_h
#define SdSpiAvr_h
// Use of in-line for AVR to save flash.
#define nop asm volatile("nop\n\t")
//------------------------------------------------------------------------------
inline void SdSpiArduinoDriver::begin(SdSpiConfig spiConfig)
{
    (void)spiConfig;
    SPI.begin();
}
//------------------------------------------------------------------------------
inline void SdSpiArduinoDriver::activate()
{
    SPI.beginTransaction(m_spiSettings);
}
//------------------------------------------------------------------------------
inline void SdSpiArduinoDriver::deactivate()
{
    SPI.endTransaction();
}
//------------------------------------------------------------------------------
inline uint8_t SdSpiArduinoDriver::receive()
{
    return SPI.transfer(0XFF);
}
//------------------------------------------------------------------------------
inline uint8_t SdSpiArduinoDriver::receive(uint8_t *buf, size_t count)
{
    if (count == 0)
    {
        return 0;
    }
    uint8_t *pr = buf;
    SPDR = 0XFF;
    while (--count > 0)
    {
        while (!(SPSR & _BV(SPIF)))
        {
        }
        uint8_t in = SPDR;
        SPDR = 0XFF;
        *pr++ = in;
        // nops to optimize loop for 16MHz CPU 8 MHz SPI
        nop;
        nop;
    }
    while (!(SPSR & _BV(SPIF)))
    {
    }
    *pr = SPDR;
    return 0;
}
//------------------------------------------------------------------------------
inline void SdSpiArduinoDriver::send(uint8_t data)
{
    SPI.transfer(data);
}
//------------------------------------------------------------------------------
inline void SdSpiArduinoDriver::send(const uint8_t *buf, size_t count)
{
    if (count == 0)
    {
        return;
    }
    SPDR = *buf++;
    while (--count > 0)
    {
        uint8_t b = *buf++;
        while (!(SPSR & (1 << SPIF)))
        {
        }
        SPDR = b;
        // nops to optimize loop for 16MHz CPU 8 MHz SPI
        nop;
        nop;
    }
    while (!(SPSR & (1 << SPIF)))
    {
    }
}
#endif // SdSpiAvr_h