System clock is abnormal during stm32f401 using TIM2.

[SWoon]

Hello,

I am using timer as stm32f401.

However, the clock set in CubeMx is different from the actual clock. (I set it to 48Mhz, but I get 2Mhz when measuring with an oscilloscope.)

I used the MCO pin to measure the PLLCLK clock, but my set clock does not come out.

Where should I look for a solution?

[Tesla DeLorean · Accepted solution]

Perhaps by looking at the code in SystemClock_Config(), and printing out the speeds

 printf("Core=%d, %d MHz\n", SystemCoreClock, SystemCoreClock / 1000000);

 printf("HCLK=%d\n", HAL_RCC_GetHCLKFreq());

 printf("APB1=%d\n", HAL_RCC_GetPCLK1Freq());

 printf("APB2=%d\n", HAL_RCC_GetPCLK2Freq());

Look at the TIM2 setup code.

Check your input clock if using HSE

[SWoon]

I checked as you told me.

The settings are out of order. However, checking the SystemClock_Config () created by cubemx did not find any problems.​

The output of the compiler is shown below.

Core = 16000000, 16 MHz

HCLK = 16000000

APB1 = 1000000

APB2 = 1000000

Below is the configuration code generated by CubeMx.

void SystemClock_Config(void)

{

 RCC_OscInitTypeDef RCC_OscInitStruct = {0};

 RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

 RCC_PeriphCLKInitTypeDef PeriphClkInitStruct = {0};

 /**Configure the main internal regulator output voltage 

 */

 __HAL_RCC_PWR_CLK_ENABLE();

 __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE2);

 /**Initializes the CPU, AHB and APB busses clocks 

 */

 RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE|RCC_OSCILLATORTYPE_LSE;

 RCC_OscInitStruct.HSEState = RCC_HSE_ON;

 RCC_OscInitStruct.LSEState = RCC_LSE_ON;

 RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;

 RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;

 RCC_OscInitStruct.PLL.PLLM = 4;

 RCC_OscInitStruct.PLL.PLLN = 96;

 RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4;

 RCC_OscInitStruct.PLL.PLLQ = 4;

 if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)

 {

  Error_Handler();

 }

 /**Initializes the CPU, AHB and APB busses clocks 

 */

 RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK

               |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;

 RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;

 RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;

 RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;

 RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

 if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1) != HAL_OK)

 {

  Error_Handler();

 }

 PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_RTC;

 PeriphClkInitStruct.RTCClockSelection = RCC_RTCCLKSOURCE_LSE;

 if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK)

 {

  Error_Handler();

 }

}

Please let me know if there are any misconfigurations (HSE clock is good).

[Tesla DeLorean]

You should use the debugger, break point the SystemClock_Config() and check that it is actually being called.

[SWoon]

Debugging at the start and end breakpoints of SystemClock_Config (). It seems to work correctly by entering a function.