Can PWM settings affect other timer settings?

[treeset]

 

 

 

#include "Main.h"

#define MAX_Intensity 1600

static volatile uint16_t Intensity = 10;

void Timer4_Configuration(void)
{
	TIM_TimeBaseInitTypeDef TIM_BaseStructure;

	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);

	TIM_BaseStructure.TIM_Prescaler = 1 - 1;
	TIM_BaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
	TIM_BaseStructure.TIM_Period = MAX_Intensity - 1;
	TIM_BaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
	TIM_TimeBaseInit(TIM4, &TIM_BaseStructure);
	TIM_Cmd(TIM4, ENABLE);
}

void PWM_Configuration()
{
	TIM_OCInitTypeDef TIM_OCStructure;
	TIM_OCStructure.TIM_OCMode = TIM_OCMode_PWM1;
	TIM_OCStructure.TIM_OutputState = TIM_OutputState_Enable;
	TIM_OCStructure.TIM_OCPolarity = TIM_OCPolarity_High;
	TIM_OCStructure.TIM_Pulse = 0;

	TIM_OC1Init(TIM4, &TIM_OCStructure);
	TIM_OC1PreloadConfig(TIM4, TIM_OCPreload_Enable);

	TIM_OC2Init(TIM4, &TIM_OCStructure);
	TIM_OC2PreloadConfig(TIM4, TIM_OCPreload_Enable);
	
	TIM_OC3Init(TIM4, &TIM_OCStructure);
	TIM_OC3PreloadConfig(TIM4, TIM_OCPreload_Enable);
	
	TIM_OC4Init(TIM4, &TIM_OCStructure);
	TIM_OC4PreloadConfig(TIM4, TIM_OCPreload_Enable);

}

void GPIO_PWM_Configuration()
{
	GPIO_InitTypeDef GPIO_InitStructure;
	RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);

	GPIO_PinAFConfig(GPIOD, GPIO_PinSource12, GPIO_AF_TIM4);
	GPIO_PinAFConfig(GPIOD, GPIO_PinSource13, GPIO_AF_TIM4);
	GPIO_PinAFConfig(GPIOD, GPIO_PinSource14, GPIO_AF_TIM4);
	GPIO_PinAFConfig(GPIOD, GPIO_PinSource15, GPIO_AF_TIM4);

	GPIO_InitStructure.GPIO_Pin = ALL_LEDS;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
	GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
	GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
	GPIO_Init(GPIOD, &GPIO_InitStructure);
}

void TIM2_Configuration(u32 Intervalms)
{
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

	TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

	TIM_TimeBaseStructure.TIM_Prescaler = 16000-1;
	TIM_TimeBaseStructure.TIM_Period 	 = Intervalms-1;
	TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
	TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

	TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
	TIM_Cmd(TIM2, ENABLE);

	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
	NVIC_InitTypeDef NVIC_InitStructure;

	NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

	NVIC_Init(&NVIC_InitStructure);
}


int main(void)
{
	

	GPIO_PWM_Configuration();
 
	Timer4_Configuration();
	
	PWM_Configuration();
	
	TIM2_Configuration(500);
	
	while(1)
	{
	}
}



void TIM2_IRQHandler()
{
	if(TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET)
	{
		if(Intensity > MAX_Intensity)
		{
			Intensity = 10;
		}
		TIM4->CCR1 = Intensity;
		TIM4->CCR2 = Intensity;
		TIM4->CCR3 = Intensity;
		TIM4->CCR4 = Intensity;

		Intensity = Intensity * 2;
		
		TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
	}
}

 

 

 

The code above is the example I am referring to. However, the Timer2 interrupt does not occur in this code. However, if you change the Timer2Configuration function call to before the PWM_Configuration function call, the interrupt operates normally. I can't find the cause of this behavior, so I'm asking a question.

i'm conducting practice using STM32F407G-DISC1.

 

[Sarra.S]

Hello @treeset, welcome to ST community, 

I think that the part in the TIM2 configuration that makes it work is the NVIC configuration, it's mandatory to configure the NVIC before enabling interrupts 

[SabTuna]

int main(void)
{
 GPIO_PWM_Configuration();
 TIM2_Configuration(500);
 Timer4_Configuration();
 PWM_Configuration();
 while(1)
 {
 }
}

Try like this.

[treeset]

If you make this modification, PWM will operate normally. However, I think it is strange that it works normally even though I simply changed the calling order. Do you know what the cause is?

[SabTuna]

The issue occurs because the NVIC_PriorityGroupConfig() function, which sets the interrupt priority grouping, must be called before any interrupt configurations; if you call PWM_Configuration() before TIM2_Configuration(), it's possible that PWM_Configuration() or functions it invokes alter the NVIC settings, overwriting the priority settings for TIM2 and preventing its interrupt from occurring; by moving the NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1); call to the very beginning of main()—before any other configurations—you ensure that the priority grouping is set correctly before any interrupts are configured, which resolves the issue.