Added SPI burst mode to spi 8 bit.

Dependents:   Bicycl_Computer_NUCLEO-F411RE Bicycl_Computer_NUCLEO-L476RG

Fork of UniGraphic by GraphicsDisplay

Added SPI burst mode to this graphics driver. If whoever wants this rolled in to repository let me know. I replaced _spi.write(); with fastWrite(); and clearRX();

SPI8.cpp

// need to re-create SPI firmware to access SPI handle
static SPI_HandleTypeDef SpiHandle;

void SPI8::fastWrite(int data) {
    
      SpiHandle.Instance = SPI1;
    // Check if data is transmitted
    while ((SpiHandle.Instance->SR & SPI_SR_TXE) == 0);
    SpiHandle.Instance->DR = data;
}
    
void SPI8::clearRX( void ) {
        SpiHandle.Instance = SPI1;
    //Check if the RX buffer is busy
    //While busy, keep checking
    while (SpiHandle.Instance->SR & SPI_SR_BSY){   
        // Check RX buffer readable
        while ((SpiHandle.Instance->SR & SPI_SR_RXNE) == 0);
        int dummy = SpiHandle.Instance->DR;
    }
}      

no such method: docs