/** Get a received value out of the SPI receive buffer in slave mode
*
* Blocks until a value is available
* @param[in] obj The SPI peripheral to read
* @return The value received
*/
int spi_slave_read(spi_t *obj)
{
int count = 0;
struct spi_s *spiobj = SPI_S(obj);
/* wait the SPI receive buffer is not empty */
while ((RESET == spi_i2s_flag_get(spiobj->spi, SPI_FLAG_RBNE)) && (count++ < 1000));
if (count >= 1000) {
return -1;
} else {
return spi_i2s_data_receive(spiobj->spi);
}
}
/** Write a byte out in master mode and receive a value
*
* @param[in] obj The SPI peripheral to use for sending
* @param[in] value The value to send
* @return Returns the value received during send
*/
int spi_master_write(spi_t *obj, int value)
{
int count = 0;
struct spi_s *spiobj = SPI_S(obj);
/* wait the SPI transmit buffer is empty */
while ((RESET == spi_i2s_flag_get(spiobj->spi, SPI_FLAG_TBE)) && (count++ < 1000));
if (count >= 1000) {
return -1;
} else {
spi_i2s_data_transmit(spiobj->spi, value);
}
count = 0;
/* wait the SPI receive buffer is not empty */
while ((RESET == spi_i2s_flag_get(spiobj->spi, SPI_FLAG_RBNE)) && (count++ < 1000));
if (count >= 1000) {
return -1;
} else {
return spi_i2s_data_receive(spiobj->spi);
}
}
static rt_uint32_t xfer(struct rt_spi_device* device, struct rt_spi_message* message)
{
struct rt_spi_bus * gd32_spi_bus = (struct rt_spi_bus *)device->bus;
struct gd32f4_spi *f4_spi = (struct gd32f4_spi *)gd32_spi_bus->parent.user_data;
struct rt_spi_configuration * config = &device->config;
struct gd32_spi_cs * gd32_spi_cs = device->parent.user_data;
uint32_t spi_periph = f4_spi->spi_periph;
RT_ASSERT(device != NULL);
RT_ASSERT(message != NULL);
/* take CS */
if(message->cs_take)
{
gpio_bit_reset(gd32_spi_cs->GPIOx, gd32_spi_cs->GPIO_Pin);
DEBUG_PRINTF("spi take cs\n");
}
{
if(config->data_width <= 8)
{
const rt_uint8_t * send_ptr = message->send_buf;
rt_uint8_t * recv_ptr = message->recv_buf;
rt_uint32_t size = message->length;
DEBUG_PRINTF("spi poll transfer start: %d\n", size);
while(size--)
{
rt_uint8_t data = 0xFF;
if(send_ptr != RT_NULL)
{
data = *send_ptr++;
}
// Todo: replace register read/write by gd32f4 lib
//Wait until the transmit buffer is empty
while(RESET == spi_i2s_flag_get(spi_periph, SPI_FLAG_TBE));
// Send the byte
spi_i2s_data_transmit(spi_periph, data);
//Wait until a data is received
while(RESET == spi_i2s_flag_get(spi_periph, SPI_FLAG_RBNE));
// Get the received data
data = spi_i2s_data_receive(spi_periph);
if(recv_ptr != RT_NULL)
{
*recv_ptr++ = data;
}
}
DEBUG_PRINTF("spi poll transfer finsh\n");
}
else if(config->data_width <= 16)
{
const rt_uint16_t * send_ptr = message->send_buf;
rt_uint16_t * recv_ptr = message->recv_buf;
rt_uint32_t size = message->length;
while(size--)
{
rt_uint16_t data = 0xFF;
if(send_ptr != RT_NULL)
{
data = *send_ptr++;
}
//Wait until the transmit buffer is empty
while(RESET == spi_i2s_flag_get(spi_periph, SPI_FLAG_TBE));
// Send the byte
spi_i2s_data_transmit(spi_periph, data);
//Wait until a data is received
while(RESET == spi_i2s_flag_get(spi_periph, SPI_FLAG_RBNE));
// Get the received data
data = spi_i2s_data_receive(spi_periph);
if(recv_ptr != RT_NULL)
{
*recv_ptr++ = data;
}
}
}
}
/* release CS */
if(message->cs_release)
{
gpio_bit_set(gd32_spi_cs->GPIOx, gd32_spi_cs->GPIO_Pin);
DEBUG_PRINTF("spi release cs\n");
}
return message->length;
};
