Unstable external priorities scheduling on stm32f4 discovery

[d4ng3r09]

Posted on December 02, 2014 at 22:15

Hi,

I am playing with stm32f4 discovery board's external interrupts. Consider 2 external interrupts:one is higher priority than the other.What i am trying to do is to decrment the priority of the higher priority task so i won t be preempted if the other flag is set.But i find that this is very unstable.Sometimes it works and sometimes no. Here is my code (i know i can make some optimasations but it is not my purpose right now) Thank you for your attention

#include ''stm32f4xx.h''
#include ''stm32f4xx_syscfg.h''
#include ''stm32f4xx_rcc.h''
#include ''stm32f4xx_gpio.h''
#include ''stm32f4xx_exti.h''
#include ''misc.h''
#include ''stm32f4xx_tim.h''
EXTI_InitTypeDef EXTI_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
void EXTILine0_Config(void);
void EXTILine1_Config(void);
void LEDInit(void);
/* Private functions ---------------------------------------------------------*/
/**
* @brief EXTI Example program
* @param None
* @retval None
*/
void main(void)
{
LEDInit();
configTimerAndGpio();
EXTILine0_Config();
EXTILine1_Config();
while (1)
{
}
}
void configTimerAndGpio() {
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;
TIM_TimeBaseInitStruct.TIM_Period = 2000-1;
TIM_TimeBaseInitStruct.TIM_Prescaler = 16000-1;
TIM_TimeBaseInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInitStruct.TIM_RepetitionCounter=0;
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStruct);
TIM_Cmd(TIM2, ENABLE);
}
//delay 2 seconds
void delay() {
TIM_Cmd(TIM2, ENABLE);
while (1) {
if (TIM_GetFlagStatus(TIM2, TIM_FLAG_Update) != RESET)
{TIM_ClearFlag(TIM2, TIM_FLAG_Update);
break;
}
}
TIM_Cmd(TIM2, DISABLE);
}
void LEDInit()
{
GPIO_InitTypeDef GPIO_InitStructure;
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);
/* Configure the GPIO_LED pin */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_All;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOD, &GPIO_InitStructure);
}
void EXTILine0_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_DOWN;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_Init(GPIOA, &GPIO_InitStructure);
SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource0);
/* Configure EXTI Line0 */
EXTI_InitStructure.EXTI_Line = EXTI_Line0;
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure);
NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x01;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x01;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
/**
* @brief This function handles External line 0 interrupt request.
* @param None
* @retval None
*/
void EXTI0_IRQHandler(void)
{
if(EXTI_GetITStatus(EXTI_Line0) != RESET)
{
/* Toggle LED1 */
GPIO_SetBits(GPIOD, GPIO_Pin_12);
delay();
delay();
GPIO_ResetBits(GPIOD,GPIO_Pin_12);//vert
/* Clear the EXTI line 0 pending bit */
EXTI_ClearITPendingBit(EXTI_Line0);
}
}
void EXTILine1_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
/* Enable GPIOA clock */
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
/* Enable SYSCFG clock */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);
/* Configure PA0 pin as input floating */
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_DOWN;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* Connect EXTI Line0 to PA0 pin */
SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource1);
/* Configure EXTI Line0 */
EXTI_InitStructure.EXTI_Line = EXTI_Line1;
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure);
/* Enable and set EXTI Line0 Interrupt to the lowest priority */
NVIC_InitStructure.NVIC_IRQChannel = EXTI1_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x02;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x02;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
void EXTI1_IRQHandler(void)
{
if(EXTI_GetITStatus(EXTI_Line1) != RESET)
{ NVIC_InitStructure.NVIC_IRQChannel = EXTI1_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x01;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x01;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
/* Toggle LED1 */
GPIO_SetBits(GPIOD, GPIO_Pin_13);//orange
delay();
delay();
/* Clear the EXTI line 0 pending bit */
GPIO_ResetBits(GPIOD,GPIO_Pin_13);
NVIC_InitStructure.NVIC_IRQChannel = EXTI1_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x02;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x02;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
EXTI_ClearITPendingBit(EXTI_Line1);
}
}