int spi_master_write(spi_t *obj, int value)
{
TSB_SSP_TypeDef* spi;
spi = obj->spi;
// Clear all data in transmit FIFO and receive FIFO
spi_clear_FIFOs(spi);
// Transmit data
SSP_SetTxData(spi, value);
// Wait for transmitting
while (SSP_GetWorkState(spi) == BUSY);
// Read received data
value = SSP_GetRxData(spi);
return value;
}
static void spi_clear_FIFOs(TSB_SSP_TypeDef *spi)
{
SSP_FIFOState tx_buf_state, rx_buf_state;
do {
while (SSP_GetWorkState(spi) == BUSY);
// Get data from receive FIFO
SSP_GetRxData(spi);
// Check receive FIFO
rx_buf_state = SSP_GetFIFOState(spi, SSP_RX);
// Check transmit FIFO
tx_buf_state = SSP_GetFIFOState(spi, SSP_TX);
} while (rx_buf_state != SSP_FIFO_EMPTY || tx_buf_state != SSP_FIFO_EMPTY);
}
/* SSP_LoopBack function */
void SSP_LoopBack(void)
{
SSP_InitTypeDef initSSP;
SSP_FIFOState fifoState;
uint16_t datTx = 0U; /* must use 16bit type */
uint32_t cntTx = 0U;
uint32_t cntRx = 0U;
uint16_t receive = 0U;
uint16_t Rx_Buf[MAX_BUFSIZE] = { 0U };
uint16_t Tx_Buf[MAX_BUFSIZE] = { 0U };
SystemInit();
/* enable the LED on board to display some info */
UART_Configuration(UART);
UART_Print(UART, "This is an example for SSP module!\n\r");
/* configure the SSP module */
initSSP.FrameFormat = SSP_FORMAT_SPI;
/* default is to run at maximum bit rate */
initSSP.PreScale = 2U;
initSSP.ClkRate = 1U;
/* define BITRATE_MIN to run at minimum bit rate */
/* BitRate = fSYS / (PreScale x (1 + ClkRate)) */
#ifdef BITRATE_MIN
initSSP.PreScale = 254U;
initSSP.ClkRate = 255U;
#endif
initSSP.ClkPolarity = SSP_POLARITY_LOW;
initSSP.ClkPhase = SSP_PHASE_FIRST_EDGE;
initSSP.DataSize = 16U;
initSSP.Mode = SSP_MASTER;
SSP_Init(&initSSP);
/* enable loop back mode for self test */
SSP_SetLoopBackMode(ENABLE);
/* enable and run SSP module */
SSP_Enable();
while (1) {
datTx++;
/* send data if Tx FIFO is available */
fifoState = SSP_GetFIFOState(SSP_TX);
if ((fifoState == SSP_FIFO_EMPTY) || (fifoState == SSP_FIFO_NORMAL)) {
SSP_SetTxData(datTx);
if (cntTx < MAX_BUFSIZE) {
Tx_Buf[cntTx] = datTx;
cntTx++;
} else {
/* do nothing */
}
} else {
/* do nothing */
}
/* check if there is data arrived */
fifoState = SSP_GetFIFOState(SSP_RX);
if ((fifoState == SSP_FIFO_FULL) || (fifoState == SSP_FIFO_NORMAL)) {
receive = SSP_GetRxData();
if (cntRx < MAX_BUFSIZE) {
Rx_Buf[cntRx] = receive;
cntRx++;
} else {
/* Place a break point here to check if receive data is right. */
/* Success Criteria: */
/* Every data transmited from Tx_Buf is received in Rx_Buf. */
/* When the line "#define BITRATE_MIN" is commented, the SSP is run in maxium */
/* bit rate, so we can find there is enough time to transmit date from 1 to */
/* MAX_BUFSIZE one by one. but if we uncomment that line, SSP is run in */
/* minimum bit rate, we will find that receive data can't catch "datTx++", */
/* in this so slow bit rate, when the Tx FIFO is available, the cntTx has */
/* been increased so much. */
__NOP();
}
} else {
/* do nothing */
}
sprintf(message, "Received data is %d\n\r" + (uint8_t)(receive / 8000));
UART_Print(UART, message);
}
}
void SSP_LoopBack(void)
{
SSP_InitTypeDef initSSP;
SSP_FIFOState fifoState;
uint16_t datTx = 0U; /* must use 16bit type */
uint32_t cntTx = 0U;
uint32_t cntRx = 0U;
uint16_t receive = 0U;
uint16_t Rx_Buf[MAX_BUFSIZE] = { 0U };
uint16_t Tx_Buf[MAX_BUFSIZE] = { 0U };
/* configure the SSP module */
initSSP.FrameFormat = SSP_FORMAT_SPI;
/* default is to run at maximum bit rate */
initSSP.PreScale = 2U;
initSSP.ClkRate = 1U;
/* define BITRATE_MIN to run at minimum bit rate */
/* BitRate = fSYS / (PreScale x (1 + ClkRate)) */
#ifdef BITRATE_MIN
initSSP.PreScale = 254U;
initSSP.ClkRate = 255U;
#endif
initSSP.ClkPolarity = SSP_POLARITY_LOW;
initSSP.ClkPhase = SSP_PHASE_FIRST_EDGE;
initSSP.DataSize = 16U;
initSSP.Mode = SSP_MASTER;
SSP_Init(TSB_SSP0, &initSSP);
/* enable loop back mode for self test */
SSP_SetLoopBackMode(TSB_SSP0, ENABLE);
/* enable and run SSP module */
SSP_Enable(TSB_SSP0);
/* initialize LEDs on M366-SK board before display something */
GPIO_SetOutput(GPIO_PA,0xFFU);
GPIO_WriteData(GPIO_PA,0xFFU);
while (1) {
datTx++;
/* send data if Tx FIFO is available */
fifoState = SSP_GetFIFOState(TSB_SSP0, SSP_TX);
if ((fifoState == SSP_FIFO_EMPTY) || (fifoState == SSP_FIFO_NORMAL)) {
SSP_SetTxData(TSB_SSP0, datTx);
if (cntTx < MAX_BUFSIZE) {
Tx_Buf[cntTx] = datTx;
cntTx++;
} else {
/* do nothing */
}
} else {
/* do nothing */
}
/* check if there is data arrived */
fifoState = SSP_GetFIFOState(TSB_SSP0, SSP_RX);
if ((fifoState == SSP_FIFO_FULL) || (fifoState == SSP_FIFO_NORMAL)) {
receive = SSP_GetRxData(TSB_SSP0);
if (cntRx < MAX_BUFSIZE) {
Rx_Buf[cntRx] = receive;
cntRx++;
} else {
/* Place a break point here to check if receive data is right. */
/* Success Criteria: */
/* Every data transmited from Tx_Buf is received in Rx_Buf. */
/* When the line "#define BITRATE_MIN" is commented, the SSP is run in maxium */
/* bit rate, so we can find there is enough time to transmit date from 1 to */
/* MAX_BUFSIZE one by one. but if we uncomment that line, SSP is run in */
/* minimum bit rate, we will find that receive data can't catch "datTx++", */
/* in this so slow bit rate, when the Tx FIFO is available, the cntTx has */
/* been increased so much. */
__NOP();
result = Buffercompare(Tx_Buf, Rx_Buf, MAX_BUFSIZE);
}
} else {
/* do nothing */
}
DisplayLED(receive);
}
}