STM32WL33KCV TCXO

[nabilkontar]

Dear Experts,

I have an E04-400 module which contains a 48 MHz tcxo controlled through PB1 pin.

If i set the module to use HSI it can work (blinks an LED, radio is off)

If i set the module to use HSE (and set PB1 to 1 directly when main.c starts) the module doesn't even reach the stage where it is able to blink an LED.

I am using cubemx 6.17.0 to generate the code.

Here's part of main.c file

int main(void)
{
/* USER CODE BEGIN 1 */
// === CRITICAL: Power TCXO BEFORE any clock configuration ===
__HAL_RCC_GPIOB_CLK_ENABLE();
HAL_GPIO_WritePin(GPIOB, GPIO_PIN_1, GPIO_PIN_SET); // TCXO_EN = High

// Reliable delay on HSI (before SysTick/HAL_Init)
for(volatile uint32_t i = 0; i < 160000; i++); // ~10-15 ms
/* 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();

/* Configure the peripherals common clocks */
PeriphCommonClock_Config();

/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */

/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_USART1_UART_Init();
MX_RTC_Init();
MX_MRSUBG_Init();

/* USER CODE BEGIN 2 */
//rf_tx_init();
/* USER CODE END 2 */

/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
  HAL_Delay(500);
  HAL_GPIO_TogglePin(LED1_GPIO_Port, LED1_Pin);

  //process_tx();
  /* USER CODE END WHILE */

/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}

void SystemClock_Config(void)
{
 RCC_OscInitTypeDef RCC_OscInitStruct = {0};
 RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

 /** Initializes the RCC Oscillators according to the specified parameters
 * in the RCC_OscInitTypeDef structure.
 */
 RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE|RCC_OSCILLATORTYPE_HSI
   |RCC_OSCILLATORTYPE_LSE;
 RCC_OscInitStruct.HSEState = RCC_HSE_ON;
 RCC_OscInitStruct.LSEState = RCC_LSE_ON;
 if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
 {
  Error_Handler();
 }

 /** Configure the SYSCLKSource and SYSCLKDivider
 */
 RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_DIRECT_HSE;
 RCC_ClkInitStruct.SYSCLKDivider = RCC_DIRECT_HSE_DIV1;
 if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_WAIT_STATES_1) != HAL_OK)
 {
  Error_Handler();
 }
}

---

Edited to apply source code formatting - please see How to insert source code for future reference.

[Andrew Neil]

---

@nabilkontar wrote:

I have an E04-400 module which contains a 48 MHz tcxo 

---

You mean this: https://ebyteiot.com/products/e04-400m16s-s2-lp-rf-wireless-transceiver-module-433m-low-power-consumption-470mhz-long-range-spi-module ?

That's a 3rd-party product - not ST's - so you really need to go to EBYTE (the manufacturer) for support:

https://ebyteiot.com/pages/contact-us

Have you checked their documentation for advice on how to use the TCXO ?

[nabilkontar]

No it is an STM32WL33KCV mcu with a 48 MHz HSE TCXO.

When configured to run from HSI it works (can blink an LED). When HSE is enabled and configured to run the same code it does not. So i assumed it is something related to TCXO.

Note i also have NUCLEO-WL-33CC2 and it's working like a charm. Tx and Rx and everything...

So the question is when using a TCXO on STM32WL33KCV (and that TCXO is controlled by PB1), is there a specific sequence to initialize the code?

I know it is not ST's product, but would appreciate guidance here.

Thank you!

[nabilkontar]

It's a E04-400M20S

[Andrew Neil]

---

@nabilkontar wrote:

So the question is when using a TCXO on STM32WL33KCV (and that TCXO is controlled by PB1), is there a specific sequence to initialize the code?

---

Again, that's the 3rd-party's design - so you really need to ask them about it.

Have you checked their documentation for any guidance, recommendations, etc.

---

@nabilkontar wrote:

Note i also have NUCLEO-WL-33CC2 and it's working like a charm.

---

And is that running with an external clock?

The only thing the STM32 actually cares about is that it's an external clock signal - it neither knows nor cares about the source of the clock.

As for any external oscillator, The HSE will need to be in bypass mode.

[Andrew Neil]

---

@nabilkontar wrote:

It's a E04-400M20S

---

So this: https://www.cdebyte.com/products/E04-400M20S ?

Always best to give a link - so people can be sure what you're referring to.

That page says they have open-source code available:

have you looked at that, to see how they manage their TCXO ?

[nabilkontar]

Hello Andrew,

Yes that is the module.

Thank you for the advice. In the process of communicating with them and asking them for sample code. Will post it here once it works (or if i made a mistake somewhere).

Went as far as de-soldering the shield to make sure PB1 is the correct pin.

Thank you again!

[Filippo_Malleo · Accepted solution]

Hi nabilkontar,

you must initialize PB1 as output before using it.

BR,
Filippo

[nabilkontar]

Hello Filippo

Thank you! it worked and Tx is working. indeed i had to initialize PB1 before using it.

Thank you!