STM32 Study Notes--EXTI

      PA1 ... PF1 share an interrupt flag EXT1
       . .
       . .
     PA15... PF15 share an interrupt flag EXT15
2. EXT5-9 share an interrupt source
      EXT10-15 share an interrupt source   
3. Before enabling interrupts, you need to ENABLE the multiplexing function of the IO port (AFIO)      
4. Set the interrupt IO port
5. Register the IO port to the interrupt line (map the IO port to the interrupt line N)
Example: GPIO_EXTILineConfig(GPIO_PortSourceGPIOD, GPIO_PinSource3); Register GPIOD.3 to　　　　　　　　　　　　　　　　　　

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　Interrupt line EXTIline3
       GPIO_EXTILineConfig(GPIO_PortSourceGPIOD, GPIO_PinSource4); Register GPIOD.4 to

                                                                                                                                    Interrupt line EXTIline4
6. Configure interrupt
   EXTI_InitStructure.EXTI_Line = EXTI_Line3;
   EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt; Interrupt
                                                            = EXTI_Mode_Event event (trigger other modules)
   EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising Rising edge trigger
                                                              = EXTI_Trigger_Falling Falling edge trigger
                                                              = EXTI_Trigger_Rising_Falling Pulse trigger
7. Configure NVIC   
8. If you use the library function to write interrupts, you must open the corresponding interrupt in stm32f10x_conf.h
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Example:
RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOD|RCC_APB2Periph_AFIO, ENABLE);
                                                                                                                             /* PD3,4,5,6 key input*/
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3|GPIO_Pin_4|GPIO_Pin_5|GPIO_Pin_6;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; //Pull-up input
GPIO_Init(GPIOD, &GPIO_InitStructure);

/* Connect the IO port to the interrupt line*/
GPIO_EXTILineConfig(GPIO_PortSourceGPIOD, GPIO_PinSource3);
GPIO_EXTILineConfig(GPIO_PortSourceGPIOD, GPIO_PinSource4);
GPIO_EXTILineConfig(GPIO_PortSourceGPIOD, GPIO_PinSource5);
GPIO_EXTILineConfig(GPIO_PortSourceGPIOD, GPIO_PinSource6);
/* Configure interrupt line 3 as falling edge Trigger*/ 
EXTI_InitStructure.EXTI_Line = EXTI_Line3;
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising_Falling;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure);
/*Others are falling edge triggers*/
EXTI_InitStructure.EXTI_Line = EXTI_Line4|EXTI_Line5|EXTI_Line6;
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(& EXTI_InitStructure);