Everything works great except MISO. I'm doing a 4 byte frame and load SPITX after each SPIRx byte is received but only the SPITX byte loaded before the master starts is returned. It is returned 4 times even though I put a new value in SPITX after each byte is received. Here's my code. Any suggestions?
Also where can I find SPI example code? I've been searching.
/* Buffers */
UINT_8 spiRxBuff[SPI_MSG_NUM_RX_BYTES];
UINT_8 spiTxBuff[SPI_MSG_NUM_TX_BYTES];
/* Counters/Pointers */
UINT_8 spiRxCount;
enum SPIState spiState;
/* SPI busy semifore */
bool Spi_Busy = FALSE;
/* Local Prototypes */
__arm void spiRxTimeout(void);
void SPIInit(void)
{
/* Configure Port */
SPICON = 0; // Clear SPI Con to start
SPICON = (SPICON_XFER_AND_INT_MODE |
SPICON_SPI_ENABLE | // Enable
SPICON_SPIRX_OVERFLOW_OVERWRITE | // Overwrite Rx data
SPICON_SLAVE_OUTPUT_ENABLE); // Enable MISO
SPICON &= ~SPICON_XFER_AND_INT_MODE; // Rx ISR
SPIDIV = 0x00; // Max speed of 3.482MHz (TODO: Valid for slave?)
/* Init Queue */
spiRxCount = 0;
spiState = SPI_STATE_IDLE;
FIQEN = SPI_SLAVE_BIT;
}
UINT_8 SPI_temp[4];
void SPIINT(void)
{
UINT_32 intFlags;
UINT_8 rxByte;
intFlags = SPISTA; // Local copy of spiStatus reg
/* Check to see if the Rx buffer is full (1 byte depth) */
if (intFlags & SPISTA_SPIRX_IRQ)
{
rxByte = SPIRX; // Read Rx Byte
if(spiState != SPI_STATE_PROCESSING) // Ignore new command if still processing the last command
{
spiRxBuff[spiRxCount++] = rxByte; // Save byte then bump index
if (spiRxCount < SPI_MSG_NUM_RX_BYTES)
{
SPITX = spiTxBuff[spiRxCount]; // Get next byte ready to send
SPI_temp[spiRxCount] = spiTxBuff[spiRxCount]; // Get next byte ready to send
spiState = SPI_STATE_COLLECTING;
}
else
{
FIQCLR = SPI_SLAVE_BIT; // Disenable SPI until data processed
/* Change msg state */
spiState = SPI_STATE_PROCESSING;
/* Process Message */
taskEnqueue(&CommandResponseExecuteCommand);
FIQCLR = SPI_SLAVE_BIT; // Disenable SPI until data processed
}
}
}
}
