/** SPI receive multiple bytes */
uint8_t SdSpiAltDriver::receive(uint8_t* buf, size_t n) {
Spi* pSpi = SPI0;
int rtn = 0;
#if USE_SAM3X_DMAC
// clear overrun error
uint32_t s = pSpi->SPI_SR;
spiDmaRX(buf, n);
spiDmaTX(0, n);
uint32_t m = millis();
while (!dmac_channel_transfer_done(SPI_DMAC_RX_CH)) {
if ((millis() - m) > SAM3X_DMA_TIMEOUT) {
dmac_channel_disable(SPI_DMAC_RX_CH);
dmac_channel_disable(SPI_DMAC_TX_CH);
rtn = 2;
break;
}
}
if (pSpi->SPI_SR & SPI_SR_OVRES) {
rtn |= 1;
}
#else // USE_SAM3X_DMAC
for (size_t i = 0; i < n; i++) {
pSpi->SPI_TDR = 0XFF;
while ((pSpi->SPI_SR & SPI_SR_RDRF) == 0) {}
buf[i] = pSpi->SPI_RDR;
}
#endif // USE_SAM3X_DMAC
return rtn;
}
/** SPI receive multiple bytes */
uint8_t spiRec(uint8_t* buf, size_t len) {
Spi* pSpi = SPI0;
int rtn = 0;
#if USE_SAM3X_DMAC
// clear overrun error
uint32_t s = pSpi->SPI_SR;
spiDmaRX(buf, len);
spiDmaTX(0, len);
uint32_t m = millis();
while (!dmac_channel_transfer_done(SPI_DMAC_RX_CH)) {
if ((millis() - m) > SAM3X_DMA_TIMEOUT) {
dmac_channel_disable(SPI_DMAC_RX_CH);
dmac_channel_disable(SPI_DMAC_TX_CH);
rtn = 2;
break;
}
}
if (pSpi->SPI_SR & SPI_SR_OVRES) rtn |= 1;
#else // USE_SAM3X_DMAC
for (size_t i = 0; i < len; i++) {
pSpi->SPI_TDR = 0XFF;
while ((pSpi->SPI_SR & SPI_SR_RDRF) == 0) {}
buf[i] = pSpi->SPI_RDR;
}
#endif // USE_SAM3X_DMAC
if (bitOrder == LSBFIRST) {
for (register int i=0; i<len; i++) {
buf[i] = __REV(__RBIT(buf[i]));
}
}
return rtn;
}