STM32F769 SPI missing data

[Jonathan Roberts]

Posted on May 04, 2017 at 12:41

Hi,

I am occasionally loosing a byte on SPI reads from an external ADC and would appreciate any suggestions about how to investigate further.

Summary: I have a FreeRTOS based application running on the STM32F769I Eval board. Periodically the application reads data from an external ADC (AD7606) connected via SPI. Data reads from the ADC are using DMA. Very occasionally (~one cluster in every 250000 transfers) I lose a byte in the middle of a number of successive transfers. The missing data is visibleon the bus an external SPI Analyser. The SPI Error interrupt never triggers.

Details:

• The application is developed using the OpenSTM32 tools and CubeMX 4.19
• The AD7606 is sampled at 1000Hz, driven by a hardware timer.
• SPI & DMA Configuration
  • STM32 is the master
  • AD7606 is connected via SPI1
  • SPI Clock is 7.5MHz
  • Each SPI transfer is 16 bytes long.
  • The DMA transfer is from the SPI FIFO to external SDRAM.
  • SPI Configuration is:

    hspi1.Instance = SPI1;

    hspi1.Init.Mode = SPI_MODE_MASTER; hspi1.Init.Direction = SPI_DIRECTION_2LINES_RXONLY; hspi1.Init.DataSize = SPI_DATASIZE_8BIT; hspi1.Init.CLKPolarity = SPI_POLARITY_LOW; hspi1.Init.CLKPhase = SPI_PHASE_1EDGE; hspi1.Init.NSS = SPI_NSS_SOFT; hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_8; hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB; hspi1.Init.TIMode = SPI_TIMODE_DISABLE; hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE; hspi1.Init.CRCPolynomial = 7; hspi1.Init.CRCLength = SPI_CRC_LENGTH_DATASIZE; hspi1.Init.NSSPMode = SPI_NSS_PULSE_DISABLE;
  • The DMA & GPIO Configuration is: /**SPI1 GPIO Configuration PB4 ------> SPI1_MISO PB3 ------> SPI1_SCK */ GPIO_InitStruct.Pin = GPIO_PIN_4|GPIO_PIN_3; GPIO_InitStruct.Mode = GPIO_MODE_AF_PP; GPIO_InitStruct.Pull = GPIO_NOPULL; GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH; GPIO_InitStruct.Alternate = GPIO_AF5_SPI1; HAL_GPIO_Init(GPIOB, &GPIO_InitStruct); /* Peripheral DMA init*/ hdma_spi1_rx.Instance = DMA2_Stream0; hdma_spi1_rx.Init.Channel = DMA_CHANNEL_3; hdma_spi1_rx.Init.Direction = DMA_PERIPH_TO_MEMORY; hdma_spi1_rx.Init.PeriphInc = DMA_PINC_DISABLE; hdma_spi1_rx.Init.MemInc = DMA_MINC_ENABLE; hdma_spi1_rx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE; hdma_spi1_rx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE; hdma_spi1_rx.Init.Mode = DMA_NORMAL; hdma_spi1_rx.Init.Priority = DMA_PRIORITY_VERY_HIGH; hdma_spi1_rx.Init.FIFOMode = DMA_FIFOMODE_DISABLE; if (HAL_DMA_Init(&hdma_spi1_rx) != HAL_OK) { Error_Handler(); } __HAL_LINKDMA(spiHandle,hdmarx,hdma_spi1_rx);

• The missing data is always an entire byte for example:

  On Bus: 0x24 0x06 0x24 0x0F

  0x24

  0x23

  0x24 0x12 0x24 0x14 0x23 0xFA 0x24 0x06 0x24 0x10Received: 0x24 0x06 0x24 0x0F

  0x23

  0x24 0x12 0x24 0x14 0x23 0xFA 0x24 0x06 0x24 0x10 0x24
• As mentioned in the summary, despite the HAL layer enabling SPI error interrupts, an error is never triggered.

Thanks in advance for any suggestions.

Jonathan

#dma #spi #stm32f7 #freertos Note: this post was migrated and contained many threaded conversations, some content may be missing.

[Jonathan Roberts]

Posted on May 15, 2017 at 14:41

I have had to focus on some other issues over the past few days, but I did discover that if I reduce the SPI clock to 60/32 (1.875MHz) then it seems the problem stops occurring. This is just masking the real issue, but it does buy me a little time. I am waiting on a call back from an ST FAE who I am hoping can shed some light on the problem..

[Amel NASRI]

Posted on May 16, 2017 at 12:50

Dear

Roberts.Jonathan

‌,

As you already said, you are currently in direct contact with our local FAE in UK who will help you to more investigate your case.

But we continue check with the help of Community members here in the forum based on all details you provided. Would it be possible to share with us a reduced project that allows to reproduce the case using our Discovery or Eval board (ST boards) emulating the external ADC as you did? This will help to identify the root cause of the issue.

Best Regards,

-Amel