/**
@ingroup spi_function
@brief Send an array of bytes to to the SPI bus.
@note Can only be used if SPI_USE_BUFFER are enabled in spi_iha_defs.h
@see spi_iha_defs.h for SPI_USE_BUFFER setup.
@return SPI_OK: OK byte send to SPI bus or put in tx_buffer.\n
SPI_NO_ROOM_IN_TX_BUFFER: Buffer full no data send\n
SPI_ILLEGAL_INSTANCE: instance is null.
@param spi to send to.
@param *buf pointer to buffer to be send.
@param len no of bytes to send.
*/
uint8_t spi_send_bytes(spi_p spi, uint8_t buf[], uint8_t len) {
uint8_t result = SPI_OK;
uint32_t value;
uint8_t tmp = 0;
if (spi == NULL) {
return SPI_ILLEGAL_INSTANCE;
}
// Select correct instance
if (_this != spi ) {
_select_instance(spi);
}
// Critical section
{
// disable interrupt
spi_disable_interrupt(_spi_base, SPI_IDR_TDRE | SPI_IDR_RDRF);
// Check if buffer is free
if (len > fifo_get_free_size(spi->_spi_tx_fifo_desc)) {
result = SPI_NO_ROOM_IN_TX_BUFFER;
} else {
// If SPI in idle send the first byte
if (!_spi_active) {
_spi_active = 1;
// Send first byte
value = SPI_TDR_TD(buf[0]) | SPI_TDR_PCS(spi_get_pcs(spi->_cs_pin));
if (len == 1) {
// It was last byte
value |= SPI_TDR_LASTXFER;
}
// Send byte
_spi_base->SPI_TDR = value;
//spi_enable_interrupt(_spi_base, SPI_IER_TDRE);
tmp = 1;
}
// Put in the tx buffer
for (uint8_t i = tmp; i < len; i++) {
value = SPI_TDR_TD(buf[i]) | SPI_TDR_PCS(spi_get_pcs(spi->_cs_pin));
if (i == len-1) {
// It was last byte
value |= SPI_TDR_LASTXFER;
}
if ( fifo_push_uint32(spi->_spi_tx_fifo_desc, value) == FIFO_ERROR_OVERFLOW ) {
result = SPI_NO_ROOM_IN_TX_BUFFER;
}
}
}
// restore interrupt state
spi_enable_interrupt(_spi_base, SPI_IER_TDRE | SPI_IER_RDRF);
}
return result;
}
void spi_transmission_begin(spi_t dev, char reset_val)
{
switch (dev) {
#if SPI_0_EN
case SPI_0:
SPI_0_DEV->SPI_TDR = SPI_TDR_TD(reset_val);
break;
#endif /* SPI_0_EN */
}
}
static inline void irq_handler_transfer(Spi *spi, spi_t dev)
{
if (spi->SPI_SR & SPI_SR_RDRF) {
char data;
data = spi->SPI_RDR & SPI_RDR_RD_Msk;
data = spi_config[dev].cb(data);
spi->SPI_TDR = SPI_TDR_TD(data);
}
/* See if a thread with higher priority wants to run now */
if (sched_context_switch_request) {
thread_yield();
}
}
uint8_t spi_send_byte(spi_p spi, uint8_t byte, uint8_t last_byte)
{
uint8_t result = SPI_OK;
uint32_t value;
if (spi == NULL) {
return SPI_ILLEGAL_INSTANCE;
}
// Select correct instance
if (_this != spi ) {
_select_instance(spi);
}
// Critical section
{
// disable interrupt
spi_disable_interrupt(_spi_base, SPI_IDR_TDRE | SPI_IDR_RDRF);
value = SPI_TDR_TD(byte) | SPI_TDR_PCS(spi_get_pcs(spi->_cs_pin));
if (last_byte) {
value |= SPI_TDR_LASTXFER;
}
// If SPI in idle send the byte
if (!_spi_active) {
_spi_active = 1;
// Send byte
_spi_base->SPI_TDR = value;
} else {
// Put in the TX buffer
if ( fifo_push_uint32(spi->_spi_tx_fifo_desc, value) == FIFO_ERROR_UNDERFLOW )
result = SPI_NO_ROOM_IN_TX_BUFFER;
}
// Enable interrupt
spi_enable_interrupt(_spi_base, SPI_IER_TDRE | SPI_IER_RDRF);
}
return result;
}
int spi_transfer_byte(spi_t dev, char out, char *in)
{
Spi *spi_port;
switch (dev) {
#if SPI_0_EN
case SPI_0:
spi_port = SPI_0_DEV;
break;
#endif /* SPI_0_EN */
default:
return -1;
}
while (!(spi_port->SPI_SR & SPI_SR_TDRE));
spi_port->SPI_TDR = SPI_TDR_TD(out);
while (!(spi_port->SPI_SR & SPI_SR_RDRF));
*in = spi_port->SPI_RDR & SPI_RDR_RD_Msk;
return 1;
}