STM32H743 does not set EOT-Bit when SCK is to high
Hello STM community,
I am currently trying to get my Nucleo STM32H743ZI2 to send data via SPI to a different chip.
Im using CubeMX to generate a lot of the setup code as I´m pretty new to this chip. For the same reason, I use the HAL.
The basic configuration is:
- The STM32H7 is the master
- I'm using SPI1 with SCK on PB3 and MOSI on PB5
- 2 Line TxOnly
- Data Size 8 Bits
- NSS disabled
- spi_ker_ck = 80 Mhz, coming from PLL1 DivQ
- AXI Peripheral Clock = 200 Mhz
- APB1/2 Peripheral Clock = 100Mhz
My main loop just tries to send out data repeatedly
status = HAL_SPI_Transmit(&hspi1, &buffer, 8, 1);
HAL_Delay(1);If I set my prescaler to, lets say 8, I can see the data being transmitted with my logic analyzer without a problem. I can also see the EOT bit getting set in the SPI2S_SR register.
If I set my prescaler any higher though problems occur. I can still see the transmissions on my logic analyzer. The timing is much worse though.
After some investigating, I found the function
SPI_WaitOnFlagUntilTimeout(hspi, SPI_FLAG_EOT, RESET, tickstart, Timeout)in stm32h7xx_hal_spi.c which is the culprit. The library tries to busy wait for the EOT flag to get set which does no longer happen when i choose any prescaler >=8.
If I use the Interrupt or DMA mode to get around the busy waiting, I can only transmit once. Afterwards the functions returns HAL_BUSY. I think this supports that the EOT bit is not getting set.
What I have done:
- I have tried to increase the spi_pclk, in case the register access is to slow
- I confirmed that the peripheral clocks are active both for GPIOB (AHB3ENR bit 1) and SPI1 (ABP2ENR bit 12)
- I tried out normal Full Duplex Mode with no change.
- I tried to write a smaller value into the SPI_CR2->TSIZE field. This resulted in fewer bytes being transmitted. The problem was still the same, EOT bit was not getting set
- I´ve tried to use a completely new project with only the SPI1 interface activated. This did also not change anything.
- A whole lot of trial and error, mostly error.
I also found the stm32h47s errata sheet where 2.14.2 sounded like it could be related, but the clocks are pretty much the other way around.
What my questions are:
- Am I mistaken about which clock in CubeMx ends up as spi_ker_ck?
- Is there anything that I am missing, as to why the EOT bit might not get set?
For completeness sake, here are my init functions (CubeMx generated)
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
/** Supply configuration update enable
*/
HAL_PWREx_ConfigSupply(PWR_LDO_SUPPLY);
/** Configure the main internal regulator output voltage
*/
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
while(!__HAL_PWR_GET_FLAG(PWR_FLAG_VOSRDY)) {}
/** Initializes the RCC Oscillators according to the specified parameters
* in the RCC_OscInitTypeDef structure.
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
RCC_OscInitStruct.HSEState = RCC_HSE_BYPASS;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
RCC_OscInitStruct.PLL.PLLM = 4;
RCC_OscInitStruct.PLL.PLLN = 400;
RCC_OscInitStruct.PLL.PLLP = 2;
RCC_OscInitStruct.PLL.PLLQ = 5;
RCC_OscInitStruct.PLL.PLLR = 2;
RCC_OscInitStruct.PLL.PLLRGE = RCC_PLL1VCIRANGE_1;
RCC_OscInitStruct.PLL.PLLVCOSEL = RCC_PLL1VCOWIDE;
RCC_OscInitStruct.PLL.PLLFRACN = 0;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
/** Initializes the CPU, AHB and APB buses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2
|RCC_CLOCKTYPE_D3PCLK1|RCC_CLOCKTYPE_D1PCLK1;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.SYSCLKDivider = RCC_SYSCLK_DIV2;
RCC_ClkInitStruct.AHBCLKDivider = RCC_HCLK_DIV1;
RCC_ClkInitStruct.APB3CLKDivider = RCC_APB3_DIV2;
RCC_ClkInitStruct.APB1CLKDivider = RCC_APB1_DIV2;
RCC_ClkInitStruct.APB2CLKDivider = RCC_APB2_DIV2;
RCC_ClkInitStruct.APB4CLKDivider = RCC_APB4_DIV2;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
{
Error_Handler();
}
} hspi1.Instance = SPI1;
hspi1.Init.Mode = SPI_MODE_MASTER;
hspi1.Init.Direction = SPI_DIRECTION_2LINES_TXONLY;
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_16;
hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi1.Init.CRCPolynomial = 0x0;
hspi1.Init.NSSPMode = SPI_NSS_PULSE_ENABLE;
hspi1.Init.NSSPolarity = SPI_NSS_POLARITY_LOW;
hspi1.Init.FifoThreshold = SPI_FIFO_THRESHOLD_01DATA;
hspi1.Init.TxCRCInitializationPattern = SPI_CRC_INITIALIZATION_ALL_ZERO_PATTERN;
hspi1.Init.RxCRCInitializationPattern = SPI_CRC_INITIALIZATION_ALL_ZERO_PATTERN;
hspi1.Init.MasterSSIdleness = SPI_MASTER_SS_IDLENESS_00CYCLE;
hspi1.Init.MasterInterDataIdleness = SPI_MASTER_INTERDATA_IDLENESS_00CYCLE;
hspi1.Init.MasterReceiverAutoSusp = SPI_MASTER_RX_AUTOSUSP_DISABLE;
hspi1.Init.MasterKeepIOState = SPI_MASTER_KEEP_IO_STATE_DISABLE;
hspi1.Init.IOSwap = SPI_IO_SWAP_DISABLE;
if (HAL_SPI_Init(&hspi1) != HAL_OK)
{
Error_Handler();
}Thanks for your help
-Vincent