2021-07-27 02:02 AM
Hello. I am trying to setup SPI1 on the STM32WB55 nucleo board. I have setup the nucleo board with the default peripheral configuration using STM32CUBEMX and I have enabled SPI1 Transmit Only Master mode:
In my code, all I am trying to do is SPI1 transmit every 1 second and I use oscilosscope to probe SP1 clock pin ( supposed to be A2 pin on the header according to the stm32wb55 nucleo datasheet.
My main.c and loop:
```
const uint8_t EEPROM_RDSR = 0b00000101;
/* USER CODE END 0 */
/**
* @brief The application entry point.
* @retval int
*/
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_USART1_UART_Init();
MX_SPI1_Init();
/* USER CODE BEGIN 2 */
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
HAL_SPI_Transmit(&hspi1, (uint8_t *)&EEPROM_RDSR, 1, 100);
HAL_Delay(1000);
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}
```
On the scope, the SPI1 clock is not toggling at all. Please suggest possible ways to debug/solve this issue
2021-07-27 03:26 AM
Hello,
I tried your code after quickly setting up a cubeMX project for this nucleo.
It is working.
I suspect you don't see the frame on the scope. Please try to remove the HAL_Delay, to have continuous transmission.
2021-07-27 04:21 AM
Hello. Thank you very much for the response. I am big noob debugging hardware and never really had an opportunity to have a look at SPI through an oscilloscope. I have managed to capture some sort of signal on clock pin with trigger option on my osciloscope. Please see the image below:
Does that look like a decent SPI clock? I have measured the time difference between the start of the spike and end of the spike and it looks like 60ns
2021-07-27 05:13 AM
Near 62.5ns + 8 spikes, it works.
The signal is not square at all.
Maybe your probe/scope need to be calibrated.
2021-07-27 05:17 AM
Once I have set the prescaler to 256, the signal is square. Now the clock period is 125Khz and that is correct since the CPU cluck frequency is 32Mhz/256 = 125kHz. Maybe my scope is too old to handle 16Mhz? Anyways, thanks. That confirmed the SPI is working as expected
2021-07-27 05:23 AM
>> Maybe my scope is too old to handle 16Mhz ?
I can't answer to that question. 🙂
Most of that time max freq it is written in front of the scope.