Posted on May 27, 2015 at 15:33Hi,
I have discover there is one extra ghost byte is sent in SPI. I have monitor the memory area of DMA TX buffer, the data there is correct, but I will receive one extra byte in the beginning.
Here is my code
/* Buffers used for transmission */
uint8_t amsgHeadBuffer[MPUHEADERSIZE];
uint8_t amsgpayloadBuffer[MPUPAYLOADSIZE];
uint8_t aRxBuffer[BUFFERSIZE];
uint8_t aTxBuffer[BUFFERSIZE];
void spi_handler_init(void)
{
SpiHandle.Instance = SPIx;
SpiHandle.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_32;
SpiHandle.Init.Direction = SPI_DIRECTION_2LINES;
SpiHandle.Init.CLKPhase = SPI_PHASE_1EDGE;
SpiHandle.Init.CLKPolarity = SPI_POLARITY_LOW;
SpiHandle.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLED;
SpiHandle.Init.CRCPolynomial = 7;
SpiHandle.Init.DataSize = SPI_DATASIZE_8BIT;
SpiHandle.Init.FirstBit = SPI_FIRSTBIT_MSB;
SpiHandle.Init.NSS = SPI_NSS_HARD_INPUT;
SpiHandle.Init.TIMode = SPI_TIMODE_DISABLED;
SpiHandle.Init.Mode = SPI_MODE_SLAVE;
if(HAL_SPI_Init(&SpiHandle) != HAL_OK) {
/* Initialization Error */
Error_Handler();
}
if(HAL_SPI_TransmitReceive_DMA(&SpiHandle, (uint8_t *)aTxBuffer, (uint8_t *)aRxBuffer, BUFFERSIZE) != HAL_OK)
{
err = 0;
Error_Handler();
}
}
void msg_handler(void)
{
int cnt = SpiHandle.hdmarx->Instance->CNDTR;
rx_index = 0;
HAL_SPI_DMAStop(&SpiHandle);
/* 1. Get MPU Message Header */
memcpy(amsgHeadBuffer, aRxBuffer+rx_index, sizeof(MpuMsgHeader_t));
rx_index += sizeof(MpuMsgHeader_t);
msg = mpu_message_header(amsgHeadBuffer);
len_mpu_payload = msg->payloadLen;
cmd_type = msg->type;
test(msg);
if(HAL_SPI_TransmitReceive_DMA(&SpiHandle, (uint8_t *)aTxBuffer, (uint8_t *)aRxBuffer, BUFFERSIZE) != HAL_OK)
{
err = 1;
Error_Handler();
}
}
void spi_write(uint8_t * buff, int size)
{
int i;
/* pull GP_nINT_PMU_PIN low for trigger interrupt */
GP_nINT_PMU_BANK->BSRR = GP_nINT_PMU_PIN ;
udelay(50);
GP_nINT_PMU_BANK->BRR = GP_nINT_PMU_PIN ;
memset(aTxBuffer, 0x00, BUFFERSIZE);
memcpy(aTxBuffer, buff, size);
}
