STM32 IO中斷方式測試頻率
阿新 • • 發佈:2020-07-20
1、STM32 IO中斷方式測試頻率有要求,頻率不能過快,目前測試2M沒問題,頻率過高中斷觸發就處理不過來。
2、過快的頻率得先降頻,用D觸發器對頻率進行降頻,如下圖所示,2、4、8、16分頻,此例用2M時鐘進行測試,對2M時鐘進行2、4、8、16分頻
3、設定一個定時器,用於計時,可用於測試一段函式使用的時間
1 void times_on(void) 2 { 3 TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; 4 5 RCC_APB1PeriphClockCmd (RCC_APB1Periph_TIM2, ENABLE);6 7 /* Time base configuration */ 8 TIM_TimeBaseStructure.TIM_Period = 0xFFFFFFFF; 9 TIM_TimeBaseStructure.TIM_Prescaler = (uint16_t) ((SystemCoreClock / 2) / 1000000) - 1; //TIM2 clocked by 1MHz 10 TIM_TimeBaseStructure.TIM_ClockDivision = 0; 11 TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;12 13 TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure); 14 TIM_ARRPreloadConfig(TIM2, ENABLE); 15 16 /* TIM Interrupts disable */ 17 TIM_ITConfig(TIM2, TIM_IT_CC1 | TIM_IT_CC2 | TIM_IT_CC3 | TIM_IT_CC4, DISABLE); 18 19 /* TIM2 enable counter */ 20 TIM_Cmd(TIM2, ENABLE); 21 22 } 23 voidtimes_off(void) 24 { 25 TIM_Cmd(TIM2, DISABLE); 26 27 } 28 29 uint32_t get_cur_times() 30 { 31 return TIM2->CNT; 32 }
4、利用IO上升沿中斷方式觸發,在中斷裡計數,比如計數10000次,也就是10000個時鐘週期
IO配置:
void gpio_config(void) { //PA0外部中斷觸發 RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA,ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE); GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN; GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz; GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; GPIO_Init(GPIOA, &GPIO_InitStructure); }
中斷配置:
void EXTI_Config(void) { EXTI_InitTypeDef EXTI_InitStructure; //PA0作為外部中斷,得相連線 SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource0); EXTI_InitStructure.EXTI_Line = EXTI_Line0;//通道 EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;//中斷 EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;//上升沿 EXTI_InitStructure.EXTI_LineCmd = ENABLE;//使能 EXTI_Init(&EXTI_InitStructure); } void NVIC_Config(void) { NVIC_InitTypeDef NVIC_InitStructure; NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn; //由於使用的是PA0,對應的是EXTI0通道 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //中斷使能 NVIC_Init(&NVIC_InitStructure); }
stm32f4xx_it.c 中斷函式:
#define EXIT_CNT 10000 //測試10000個時鐘週期計數 float T = 0.0; float Fre = 0.0; uint32_t exit_cnt = 0; uint8_t exit_flg = 0; __IO uint32_t time_1 = 0; __IO uint32_t time_2 = 0; void EXTI0_IRQHandler() { if(0 == exit_cnt) { time_1 = get_cur_timestamp(); //首次觸發進入中斷,獲取當前值 } EXTI_ClearITPendingBit(EXTI_Line0); exit_cnt ++; if(EXIT_CNT == exit_cnt) { time_2 = get_cur_timestamp();//計數達到設定值後,獲取當前值 exit_cnt = 0; T = (time_2 - time_1)*1.0/EXIT_CNT; //前後獲取的值做差值,算出一個時鐘週期時間 Fre = 1/T * 1000*1000; //換算出頻率 exit_flg = 1; } }
主函式:
int main(void)
{
gpio_config();
Debug_USART_Config(); timestamp_on(); //開啟定時器 EXTI_Config(); NVIC_Config(); while(1) { if(1 == exit_flg) { exit_flg = 0; printf("------------------------------------------\r\n"); printf("T = %lf(us)\r\n", T); printf("Fre = %lf(Hz)\r\n", Fre); printf("------------------------------------------\r\n"); } Delay_ms(850); }
}
測試2M源時鐘、4分頻、8分頻、16分頻結果如下: