Nios II按键中断调试程序及经验.doc

Nios II按键中断调试程序及经验软件：Quatus II 6.1,Nios II 6.1硬件：EP1C3T144 FPGA开发板实验目的:熟悉nios II开发,掌握中断程序调试系统配置：CPU+OnChipRam(4K)+LED_PIO+BUTTON_PIO功能描述：按键实现中断，使led亮或灭led配置成开发板上的led0,led1,led2,led3按键采用简单按钮B17,B18,19,B20不给过多注释了(其实注释够多了)#include #include #include sys/alt_irq.h#include altera_avalon_pio_regs.h#include system.h/* A variable to hold the value of the button pio edge capture register. */volatile int edge_capture;#ifdef BUTTON_PIO_BASE/* 按键中断服务程序*/static void handle_button_interrupts(void* context, alt_u32 id) /* Cast context to edge_captures type. It is important that this be * declared volatile to avoid unwanted compiler optimization. */ volatile int* edge_capture_ptr = (volatile int*) context; /* Store the value in the Buttons edge capture register in *context. */ *edge_capture_ptr = IORD_ALTERA_AVALON_PIO_EDGE_CAP(BUTTON_PIO_BASE); /* Reset the Buttons edge capture register. */ IOWR_ALTERA_AVALON_PIO_EDGE_CAP(BUTTON_PIO_BASE, 0);/* Initialize the button_pio. */static void init_button_pio() /* Recast the edge_capture pointer to match the alt_irq_register() function * prototype. */ void* edge_capture_ptr = (void*) &edge_capture; /* Enable all 4 button interrupts. */ IOWR_ALTERA_AVALON_PIO_IRQ_MASK(BUTTON_PIO_BASE, 0xf); /* Reset the edge capture register. */ IOWR_ALTERA_AVALON_PIO_EDGE_CAP(BUTTON_PIO_BASE, 0x0); /* Register the interrupt handler. */ alt_irq_register( BUTTON_PIO_IRQ, edge_capture_ptr, handle_button_interrupts );#endifint main (void) _attribute_ (weak, alias (alt_main);int alt_main(void) alt_irq_init(ALT_IRQ_BASE); /necessary,enable interrupts alt_sys_init(); /unnecessary alt_io_redirect(ALT_STDOUT,ALT_STDIN,ALT_STDERR);/unnecessary init_button_pio(); while(1) switch(edge_capture) case 0x01: IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE,0xFF); break; case 0x02: IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE,0x00); break; case 0x04: IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE,0xFF); break; case 0x08: IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE,0x00); break; default: IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE,0x0A); break; return 0;1 因为使用的是片上RAM,容量有限,故得重载alt_main(), 否则空间不够2 系统默认的alt_main()是干了很多活的.比如系统中断,IO设备驱动等,改写的时候得注意,哪些用户程序用到了.比如本例用到中断,故 alt_irq_init(ALT_IRQ_BASE);函数是必须的.开始没有调试成功就是因为没有开总中断中断的调试过程可以依次看以下: status:最低位PIE