在最近的工程中，需要用到PS/2键盘和鼠标作为控制输入，所以在网上找了一些相关的资料，内容很丰富，看来已经有很多人做过了这方面的编程。本篇Blog算是实践总结，为以后的开发积累一些基础知识。MicroBlaze支持重启（reset）,中断（ interrupt）, 暂停（break）和异常（ exception）。这里粗略的介绍：
- reset当 外部按键发出reset信号或者XMD通过MDM（MicroBlaze Debug module）发出reset信号，这些信号都会被proc_sys_reset模块接收，然后该模块产生一个16周期长的高电平信号至 MicroBlaze的MB_RESET管脚。MicroBlaze响应reset, PC 寄存器指向0x0地址，依照向量表中代码执行。
- exception异常是MicroBlaze对内部运行发生错误的情况发做出的响应，这些情况包括：非法指令，指令和数据总线错误和未对齐的访问(unaligned access)。如除0操作，非法操作码异常，数据总线异常等。
- breakbreak 分为software break和hardware break。hardware break，这时MDM模块的输出端口Ext_BRK和Ext_NM_BRK跟MicroBlaze对应的输入端口相连。一旦break响应，暂停返回地 址（break return address）自动装入R16寄存器中。而software break通过brk和brki指令来完成。
- interruptMicroBlaze 只支持一个外部中断源（连接于Interrupt 端口），所以需要多个中断输入的话，就得添加中断控制器(xps_intc)了。只有当机器状态寄存器(Machine Status Register,MSR)中的中断使能位（interrupt enable）置'1'，MicroBlaze才能响应中断。MicroBlaze响应中断，PC指向中断向量(地址：0x10)，R14存储了中断返回 地址。
注：具体细节问题，请见参考1。 注：该表格来自于MicroBlaze参考手册，见参考1下面具体介绍如何对MicroBlaze进行中断编程。
- 中断信号的物理连接system.mhs文件定义了物理硬件的相关信息，包括总线架构、外围设备、处理器、系统内部信号互连和地址空间等。所以这里就通过MHS定义文件给出关于中断信号互连的信息。当然MicroBlaze的中断输入，可以配置成电平触发或者边沿触发，在配置MicroBlaze的GUI或者在MicroBlaze.mpd中通过设置 C_INTERRUPT_IS_EDGE ，C_EDGE_IS_POSITIVE来完成对中断的触发的配置。BEGIN microblaze . . . PORT MB_RESET = mb_reset PORT Interrupt = InterruptENDBEGIN xps_uartlite. . . PORT Interrupt = RS232_Uart_1_InterruptENDBEGIN xps_intc. . . PORT Irq = Interrupt PORT Intr = RS232_Uart_1_Interrupt&plb_ps2_controller_0_IP2INTC_IrptENDBEGIN plb_ps2_controller. . . PORT IP2INTC_Irpt = plb_ps2_controller_0_IP2INTC_IrptPORT mouse_clk = plb_ps2_controller_0_mouse_clkPORT mouse_data = plb_ps2_controller_0_mouse_dataPORT key_clk = plb_ps2_controller_0_key_clkPORT key_data = plb_ps2_controller_0_key_dataEND
- EDK提供的驱动以及相关函数的介绍void microblaze_enable_interrupts(void)该函数使MicroBlaze可以响应中断，即MSR中的“interrupt enable”位置’1’;void microblaze_disable_interrupts(void)该函数使MicroBlaze不能响应中断，即MSR中的“interrupt enable”位置 ’0’;这几个函数都定义包含在$EDK_project/microblaze_0/include/mb_interface.h头文件中XIntc_Initialize(&InterruptController, (Xuint16)INTC_DEVICE_ID);该函数用于初始化中断控制器，主要包括初始化XIntc的结构体，初始化向量列表，以及所有中断源输入禁用，中断输出禁用。int XIntc_Connect(XIntc * InstancePtr, u8 Id, XInterruptHandler Handler, void *CallBackRef)中断源的标示和相关中断处理程序的连接。XIntc_Start(XIntcInstancePtr, XIN_REAL_MODE);该函数使得中断控制器输出的中断信号启用。XIN_REAL_MODE 意思是只允许硬件中断(hardware interrupt)void XIntc_Enable(XIntc * InstancePtr, u8 Id)该函数使得对应ID的中断源输入启用这几个函数定义在$EDK_project/microblaze_0/libsrc/intc_v1_11_a/src/xintc.c需要包含的头文件：xintc.h
- C语言编程实例/**Date 2010-12-27*author Qi Yao*decription main function code for interrupt program* such as timer or keyboard and mouse interrupt.*//* FPGA includes */#include /* for printf */#include /* for usleep */#include "xparameters.h"#include "xutil.h"#include "xintc.h"#include "plb_ps2_controller.h"#include "mb_interface.h"#define INTC_DEVICE_ID XPAR_INTC_0_DEVICE_IDint init_input(void);XStatus SetUpInterruptSystem(XIntc *XIntcInstancePtr);static XIntc InterruptController;/*Instance of the Interrupt Control*//*** Input interrupt handler*/void PS2_InterruptHandler(void *CallbackRef){ u32 mouse_state, keybd_state, flags; Xuint32 baseaddr = (Xuint32) XPAR_PLB_PS2_CONTROLLER_0_BASEADDR; /* read information from device registers */ keybd_state = ((u32 *)baseaddr)[0]; mouse_state = ((u32 *)baseaddr)[1]; flags = PLB_PS2_CONTROLLER_mReadReg(baseaddr, PLB_PS2_CONTROLLER_INTR_IPISR_OFFSET); if (flags & EVENT_FROM_MOUSE) /*mouse event handler*/ handle_mouse_event(mouse_state); if (flags & EVENT_FROM_KEYBD) /*keyboard event handler*/ handle_keybd_event(keybd_state); /* clear interrupt flags in PS/2 controller */ PLB_PS2_CONTROLLER_mWriteReg(baseaddr, PLB_PS2_CONTROLLER_INTR_IPISR_OFFSET, flags);}XStatus init_input(void){ XStatus Status; Xuint32 baseaddr = (Xuint32) XPAR_PLB_PS2_CONTROLLER_0_BASEADDR; /* initialize PS/2 interrupts */ PLB_PS2_CONTROLLER_mWriteReg(baseaddr, PLB_PS2_CONTROLLER_INTR_DIER_OFFSET, 0); PLB_PS2_CONTROLLER_mWriteReg(baseaddr, PLB_PS2_CONTROLLER_INTR_DGIER_OFFSET, 0xFFFFFFFF); PLB_PS2_CONTROLLER_mWriteReg(baseaddr, PLB_PS2_CONTROLLER_INTR_IPIER_OFFSET, 0xFFFFFFFF); PLB_PS2_CONTROLLER_mWriteReg(baseaddr, PLB_PS2_CONTROLLER_INTR_IPISR_OFFSET, 0); /* initialize Interrupt controller */ Status = XIntc_Initialize(&InterruptController, (Xuint16)INTC_DEVICE_ID); if (Status != XST_SUCCESS) { return XST_FAILURE; } Status = XIntc_SelfTest(&InterruptController); if (Status != XST_SUCCESS) { return XST_FAILURE; } /* * Connect a device driver handler that will be called when an interrupt * for the device occurs, the device driver handler performs the specific * interrupt processing for the device */ Status = XIntc_Connect(XIntcInstancePtr, XPAR_XPS_INTC_0_PLB_PS2_CONTROLLER_0_IP2INTC_IRPT_INTR, (XInterruptHandler)PS2_InterruptHandler, (void *)0); if (Status != XST_SUCCESS) { return XST_FAILURE;} /* * Start the interrupt controller such that interrupts are enabled for * all devices that cause interrupts, specify simulation mode so that * an interrupt can be caused by software rather than a real hardware * interrupt */ Status = XIntc_Start(XIntcInstancePtr, XIN_REAL_MODE); if (Status != XST_SUCCESS) { return XST_FAILURE; } /* * Enable the interrupt for the device and then cause (simulate) an * interrupt so the handlers will be called */ XIntc_Enable(XIntcInstancePtr, XPAR_XPS_INTC_0_PLB_PS2_CONTROLLER_0_IP2INTC_IRPT_INTR); /* * Enable the Interrupts for the MicroBlaze Processor */ microblaze_enable_interrupts(); return XST_SUCCESS;}int main(void){ /*Initialization*/ init_input(); /*wait for interrupt*/ while(1); return 1;}
- 汇编代码详解使用mb-objdump工具对实例进行了反汇编，想看看到底是个什么情况Disassembly of section .vectors.reset:00000000 <_start>: 0: b0009000 imm -28672 4: b8080000 brai 0 #main()程序起始地址是0x90000000Disassembly of section .vectors.sw_exception:00000008 <_vector_sw_exception>: 8: b0009000 imm -28672 c: b8080438 brai 1080Disassembly of section .vectors.interrupt:00000010 <_vector_interrupt>: 10: b0009000 imm -28672 14: b8080474 brai 1140 #中断处理程序起始地址是0x90000474Disassembly of section .vectors.hw_exception:00000020 <_vector_hw_exception>: 20: b0009000 imm -28672 24: b8080450 brai 110490000474 <__interrupt_handler>: #中断处理程序起始地址和汇编代码90000474: 3021ffb0 addik r1, r1, -8090000478: f9e10000 swi r15, r1, 09000047c: f8610020 swi r3, r1, 3290000480: f8810024 swi r4, r1, 3690000484: f8a10028 swi r5, r1, 4090000488: f8c1002c swi r6, r1, 449000048c: f8e10030 swi r7, r1, 4890000490: f9010034 swi r8, r1, 5290000494: f9210038 swi r9, r1, 5690000498: f941003c swi r10, r1, 609000049c: f9610040 swi r11, r1, 64900004a0: f9810044 swi r12, r1, 68900004a4: fa210048 swi r17, r1, 72
- 总结主要描述了MicroBlaze的中断的基本原理，以及编程。
参考文献：
来源：KiKi的博客 |
