Two boards: arduino nano and stmvldiscovery. Boards are connected by spi interface. Arduino is master device. Stm32vldiscovery is slave device. In the txBuf (transmit buffer) both board have the same data - uint8_t array (1, 2, 3, 4, 5, 6, 7, 8, 9, 10).

Both board send same data. Logic analyzer captured wrong data from stm32vldiscovery. I don't know why...

Both board have spi settings: arduino: msbfirst, freq = 1Mhz, spi_mode_0, 8 bit data; stm32: msbfirst, cpol = 0, cpha = 0, motorola frame format, same freq;

I tried set hardware/software NSS control for stm32. It haves same result. Same result I had with two boards - stm32f4-discovery and stm32vldiscovery. stm32vldiscovery was slave device same.

Why? What's wrong?

Yellow is arduino. Green is stm32. enter image description here

stm32 code:

#include "main.h"
SPI_HandleTypeDef hspi1;

uint8_t txBuff[10];
uint8_t rxBuff[10];

void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_SPI1_Init(void);

int main(void)


  for(int i = 0; i < 10; i++)
    txBuff[i] = i+1;
    rxBuff[i] = 0;

  while (1)
    HAL_SPI_TransmitRecieve(&hspi1, txBuff, rxBuff, 10, 10000);

static void MX_SPI1_Init(void)
  hspi1.Instance = SPI1;
  hspi1.Init.Mode = SPI_MODE_SLAVE;
  hspi1.Init.Direction = SPI_DIRECTION_2LINES;
  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_4;
  hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
  hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
  hspi1.Init.CRCPolynomial = 10;
  if (HAL_SPI_Init(&hspi1) != HAL_OK)

Arduino code:

#include <SPI.h>

void setup()

void loop()
    SPI.beginTransaction(SPISettings(1000000, MSBFIRST, SPI_MODE0));
    byte arr[10];
    for (int i = 0; i < 10; i++)
        arr[i] = i + 1;

    digitalWrite(SS, LOW);

    for (int i = 0; i < 10; i++)

    digitalWrite(SS, HIGH);
  • 1
    \$\begingroup\$ As for any debugging question, you must include code sufficient to demonstrate the problem. \$\endgroup\$ – Chris Stratton May 15 at 17:36
  • \$\begingroup\$ Looks like you have your STM32 configured for a different SPI mode to the Arduino. \$\endgroup\$ – brhans May 15 at 17:43
  • \$\begingroup\$ brhan, maybe, but why two stm32 with same configuration have same problems? \$\endgroup\$ – Alexey May 15 at 17:50

Today I replaced stm32vldiscovery board to stm32f4-discovery and it works fine! I think problem was in stm32vldiscovery board. Stm32vldiscovery board works badly in this mode. I can't find nothing other reasons. enter image description here


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