Question
Unable to set up SPI between 2 stm32 devices
I am trying to get 2 stm32f411's to communicate via SPI. From my understanding, there should be 1 master device while the others should be its slaves.
For my master device, I am using full-duplex master and I have disabled NSS and enabled the NSS pin as an GPIO OUTPUT pin.
For my slave device, I am using full-duplex slave and have enabled NSS INPUT SIGNAL so it knows when it needs to read.
Here are my problems:
- I have set the prescalar of the master device to 64 but am unable to set the prescalar of the slave device as there is no option to do so. I am unsure if this is a problem as I have seen an example where it is possible to set the prescalar for the slave device. However, am I unsure if it is necessary as the option disappears for me every time I set a device to slave.
- I am unsure if I need to change anything in the "clock configuration". I noticed that there is a option to enable PLLCLK for CSS but I am not sure if I need to do this or if leaving it set to HSI is ok.
- I am unable to send and receive any data.
Here is a screenshot of the clock configuration I am talking about.
Here is the code for my master device:
int main(void)
{
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_SPI2_Init();
MX_USART1_UART_Init();
/* USER CODE BEGIN 2 */
HAL_GPIO_WritePin(GPIOB, GPIO_PIN_12, GPIO_PIN_SET);
uint8_t TX_Data[] = "abcdefgh";
HAL_GPIO_WritePin(GPIOB, GPIO_PIN_12, GPIO_PIN_RESET);
HAL_SPI_Transmit(&hspi2, TX_Data, sizeof(TX_Data), 5000);
HAL_GPIO_WritePin(GPIOB, GPIO_PIN_12, GPIO_PIN_SET);
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}
static void MX_SPI2_Init(void)
{
/* USER CODE BEGIN SPI2_Init 0 */
/* USER CODE END SPI2_Init 0 */
/* USER CODE BEGIN SPI2_Init 1 */
/* USER CODE END SPI2_Init 1 */
/* SPI2 parameter configuration*/
hspi2.Instance = SPI2;
hspi2.Init.Mode = SPI_MODE_MASTER;
hspi2.Init.Direction = SPI_DIRECTION_1LINE;
hspi2.Init.DataSize = SPI_DATASIZE_8BIT;
hspi2.Init.CLKPolarity = SPI_POLARITY_LOW;
hspi2.Init.CLKPhase = SPI_PHASE_1EDGE;
hspi2.Init.NSS = SPI_NSS_SOFT;
hspi2.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_64;
hspi2.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi2.Init.TIMode = SPI_TIMODE_DISABLE;
hspi2.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi2.Init.CRCPolynomial = 10;
if (HAL_SPI_Init(&hspi2) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN SPI2_Init 2 */
/* USER CODE END SPI2_Init 2 */
}Here is the code for my slave device:
int main(void)
{
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_SPI2_Init();
MX_USART1_UART_Init();
/* USER CODE BEGIN 2 */
int8_t RX_Data[1652];
// Receive SPI Data (Blocking Mode) Polling
HAL_SPI_Receive(&hspi2, RX_Data, sizeof(RX_Data), 5000);
HAL_UART_Transmit(&huart1, RX_Data, sizeof(RX_Data), 5000);
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}
static void MX_SPI2_Init(void)
{
/* USER CODE BEGIN SPI2_Init 0 */
/* USER CODE END SPI2_Init 0 */
/* USER CODE BEGIN SPI2_Init 1 */
/* USER CODE END SPI2_Init 1 */
/* SPI2 parameter configuration*/
hspi2.Instance = SPI2;
hspi2.Init.Mode = SPI_MODE_SLAVE;
hspi2.Init.Direction = SPI_DIRECTION_2LINES;
hspi2.Init.DataSize = SPI_DATASIZE_8BIT;
hspi2.Init.CLKPolarity = SPI_POLARITY_LOW;
hspi2.Init.CLKPhase = SPI_PHASE_1EDGE;
hspi2.Init.NSS = SPI_NSS_HARD_INPUT;
hspi2.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi2.Init.TIMode = SPI_TIMODE_DISABLE;
hspi2.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi2.Init.CRCPolynomial = 10;
if (HAL_SPI_Init(&hspi2) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN SPI2_Init 2 */
/* USER CODE END SPI2_Init 2 */
}Also, please let me know if there are any good and detailed guides on spi, i2c, uart, etc.
Thank you very much for your time and help!
