DA14850 SPI的奴隶。主接收数据结合起来d byte.

Hallo,

I have setup the Dialog board as SPI slave with additional flow-control lines. When the slave sends data to the master, the master receives them on the third byte. Except the first one or two messages after a restart of the board where the data starts at the second byte, as expected. I am not using the FIFO buffers (SPI_FIFO_MODE = 0x03). I have no Idea why this is happening. Debugging has shown that spidrv_buffer_tx holds the data like it's supposed to do, without an additional zero-byte. Is there something that I'm missing here?

The SPI driver looks like this:

void SPI_Handler_RxTx(void)
{
/* indicate TXRDY INACTIVE to master = no further reception from master until application is ready! */
SPIDRV_TXRDY_L;

/* indicate RXPEND INACTIVE to master = no further transmission to master until application is ready! */
SPIDRV_RXPEND_L;

/* lock the buffers for ISR usage */
spidrv_cntrl.isr_lock = SPIDRV_CS_H_DETECTCNT;

/* Wait until data is ready */
while ( spi_data_rdy_getf() )
{
/* -------------------------------------------------------------------------------- */
/* SPI RX PART - read the received byte (if possible) */

/* transfer this byte into our rx buffer (if possible) */
if ( spidrv_cntrl.rx_wr_idx < SPIDRV_BUFFSIZE_RX )
{
spidrv_buffer_rx[spidrv_cntrl.rx_wr_idx] = 0xFF&GetWord16(SPI_RX_TX_REG0);
spidrv_cntrl.rx_wr_idx++;
}
else
{ /* do nothing, indicate an overflow error */
spidrv_cntrl.rx_overflw++;
}

/* -------------------------------------------------------------------------------- */
/* SPI TX PART - transfer one pending byte from tx buffer into tx register (if any) */
if ( spidrv_cntrl.tx_rd_idx < spidrv_cntrl.tx_cnt )
{
SetWord16(SPI_RX_TX_REG0, 0xFF&(spidrv_buffer_tx[spidrv_cntrl.tx_rd_idx]));
spidrv_cntrl.tx_rd_idx++;
}
else
{ /* tx read index reached last byte: all done! */
SetWord16(SPI_RX_TX_REG0, 0x00);
}

/* Clear pending flag */
SetWord16(SPI_CLEAR_INT_REG, 0x01);
}

// clear IRQ (raised again, if something pending)
SetWord16(SPI_CLEAR_INT_REG, 0x01);
}