https://blog.csdn.net/v13910/article/details/83540289
1.ARM interrupt system
Interrupt means do not say. The main explanation several knowledge points:
(1) ARM system, the lower memory addresses , a 32-byte cured hardware interrupt vector table.
(2) exception interrupt occurs, the program counter PC at different locations within the meaning of the abort is different. After the interrupt, the interrupt is different return address is different. However, for system reset interrupt, do not need to return , because the entire application system is to start from the reset interrupt.
Data access terminated: The address data access does not exist, or the current address is not allowed access.
Fast Interrupt Request: fast interrupt request external pins, external interrupt request than the high level, but the general peripheral interrupt request to use an external interrupt request .
Instruction prefetch termination: prefetch instruction address does not exist, or the current address can not be accessed.
Undefined instruction: ARM coprocessor or that the current instruction is undefined.
ARM interrupt process:
IRQ interrupt request occurs first in the main program, the program jumps to the interrupt IRQ interrupt to find the corresponding address vector table parser then parses the program jumps to the interrupt, and then execute the interrupt routine.
2.ZYNQ interrupt system
ZYNQ includes three interrupts: Private interrupts, software interrupts and share interrupt.
(1) Private interrupts: Private 5 connected to each CPU interrupt, the interrupt ID27-31.
(2) Software interrupts: 16 interrupt numbers: 0-15. Write interrupt number to register via the CPU ICDSGIR private bus , and to develop CPU.
(3) Shared Interrupt: receiving as GPIO, DMA, timers and other modules of the interrupt signal. Interrupt number 32-95.
The relationship between them:
3. Interrupt LED lights
A key end PL, PS side lighting LED.
First or hardware configuration, adding soft-core ZYNQ, configuration about the DDR and UART.
然后，因为要用到PL端的按键，所以要建立PL与PS之间的联系，通过EMIO或者AXI总线，EMIO能不能中断还没有研究，这里用的AXI。
1.加AXI_GPIO IP核，设置GPIO端口中断使能，GPIO宽度为1（只用了一个按键），设置方向为全输入。
（如果想控制PL端LED，就再加一个AXI_GPIO核），设置输出就可以了。
2.打开中断
IRQ_F2P是PL与PS的共享中断，下面的是两个ARM核的快速中断和外部中断（都来自PL属于CPU私有中断），私有中断如何点亮LED还没有测试。
3.PS端LED，设置I/O外设，GPIO里勾选MIO，点亮的LED管脚为MIO0。
然后自动连接，（手动连接AXI_GPIO ip2intc_irpt），绑定gpio_rtl的管脚为T17（按键），3.3V，然后输出，生成HDL Wrapper，导出硬件（包含比特流文件），载入SDK。
4.中断代码
各种初始化：
1.初始化按键：
-
status = XGpio_Initialize(&
key, KEY1_ID);
-
if(status!=XST_SUCCESS)
-
return XST_FAILURE;
-
XGpio_SetDataDirection(&
key,
1,
1);
设置单通道，方向为输入。
2.初始化LED：
-
led_config = XGpioPs_LookupConfig(LED1_ID);
-
status = XGpioPs_CfgInitialize(&led, led_config, led_config->BaseAddr);
-
if(status!=XST_SUCCESS)
-
return XST_FAILURE;
-
XGpioPs_SetDirectionPin(&led,
0,
1);
//output
-
XGpioPs_SetOutputEnablePin(&led,
0,
1);
-
XGpioPs_WritePin(&led,
0,
1);
设置MIO0为输出，使能引脚（不使能不能点亮，与AXI接PL端LED有点区别，后者不需要使能）。然后引脚写高电平，使LED初始状态为灭。
3.初始化中断：
-
status = InitIntrFunction(INTR_ID);
-
if(status!=XST_SUCCESS)
-
return XST_FAILURE;
中断初始化写成一个函数，传入参数是中断的ID，另外以上各种初始化，需要实例化XGpio、XGpioPs、XScuGic类型的变量，直接定义为全局变量，这样会比较方便。
中断函数：
-
u32 InitIntrFunction(u16 device_ID){
//INTR ID
-
XScuGic_Config* intr_config;
-
int status;
-
-
//init
-
intr_config = XScuGic_LookupConfig(device_ID);
-
status = XScuGic_CfgInitialize(&gpio_intr, intr_config, intr_config->CpuBaseAddress);
-
if(status!=XST_SUCCESS)
-
return XST_FAILURE;
-
-
//call to interrupt setup Function
-
status = InterruptSystemSetup(&gpio_intr);
-
if(status != XST_SUCCESS)
-
return XST_FAILURE;
-
-
//connect
-
status = XScuGic_Connect(&gpio_intr, INTR_GPIO, (Xil_ExceptionHandler)BTN_Intr_Handler, (void*)&key);
-
if(status!=XST_SUCCESS)
-
return XST_FAILURE;
-
-
//Enable Intr
-
XGpio_InterruptEnable(&key,
1);
-
XGpio_InterruptGlobalEnable(&key);
-
//print("Hello World");
-
-
//Enable Intr in controller
-
XScuGic_Enable(&gpio_intr, INTR_GPIO);
-
-
return XST_SUCCESS;
-
}
1.函数首先是中断初始化，与先前的按键初始化与LED初始化差不多。
2.接着是定义了一个InterruptSystemSetup函数，定义为：
-
u32 InterruptSystemSetup(XScuGic* XScuGicInstancePtr){
-
Xil_ExceptionRegisterHandler(XIL_EXCEPTION_ID_INT,
-
(Xil_ExceptionHandler)XScuGic_InterruptHandler,
-
XScuGicInstancePtr);
-
Xil_ExceptionEnable();
-
return XST_SUCCESS;
-
}
查了查，说是Xil_ExceptionRegisterHandler函数是Xilinx提供的通用异常处理程序，中断触发之后统一由XScuGic_InterruptHandler先处理，然后在HandlerTable中查找相应的处理函数。Xil_ExceptionEnable函数使能异常处理。
3.连接，我理解的就是，将这个中断与按键的行为，连接起来。XScuGic_Connect(&gpio_intr, INTR_GPIO, (Xil_ExceptionHandler)BTN_Intr_Handler, (void*)&key)，这个函数中参数的意思，第一个参数就是实例化的XScuGic对象了，第二个参数，是对应的XPAR_FABRIC_AXI_GPIO_0_IP2INTC_IRPT_INTR，也就是定义的那个中断IRQ_F2P，定义在xparameters.h里。
定义为61，这也就是IRQ_F2P的中断号为61-68和84-91，共同组成了IRQ_F2P[15:0]。
第三个参数，调用的中断处理函数，发生的中断操作写在里面。第四个参数，连接的对象，这里是按键，即将中断行为与按键行为连接起来。
4.使能中断与挂起中断。
中断调用函数：
在函数里，点亮LED即可。
5.问题
1.首先在文档里写了：
这个中断触发方式，是否是高电平触发？如果是高电平触发
没有按下的时候，输入为高电平，为何不触发呢？懂的朋友留个评论！