STM32F446RET6 Timer and clock

[Junzhe]

Hi, 

I designed the us and ms delay functions using timer 2 and 4.

Initially in the PLL source, I was using HSI, but it had some errors, so I switched it to HSE. I was using my delay function to control the DAC output, but when I switched to HSE, all my delay functions became twice as long.

This is my code.

while (1)

{

/* USER CODE END WHILE */

/* USER CODE BEGIN 3 */

HAL_DAC_SetValue(&hdac, DAC_CHANNEL_1, DAC_ALIGN_12B_R, 2854); //

Delay_us(500);

HAL_DAC_SetValue(&hdac, DAC_CHANNEL_1, DAC_ALIGN_12B_R, 868);

Delay_us(500);

HAL_DAC_SetValue(&hdac, DAC_CHANNEL_1, DAC_ALIGN_12B_R, 1861);

Delay_ms(10);

}

 This is the waveform of the oscilloscope.

 In the clock tree settings, I only switched the clock source to HSE, and the divider settings did not change. I wonder why this happened.

Best,

[TDK]

Change HSE to 8 MHz if that's what's on your board.

You don't mention your board, but most of the ST boards have this as 8 MHz.