d0fd36fc458f001c180b8a3c09c33bce

NIOSII的经典JTAG通信程序,含所有底层源代码

#include  <stdio.h>
#include  "system.h"
#include  "altera_avalon_pio_regs.h"
#include  "alt_types.h"
#include  "sys/alt_irq.h"
#include  "priv/alt_busy_sleep.h"

#define   LEDCON   0xff          // 
#define   KEYCON   0xff          // 


alt_u32  done = 0;                   // 信号量：通知外部中断事件发生

/********************************************************************
* 功    能：键按下事件中断服务子程序，当键按下时，通过done标志
*           告知外界
********************************************************************/
static void KeyDown_interrupts(void* context, alt_u32 id)
{  
   /* 清中断捕获寄存器 */
   IOWR_ALTERA_AVALON_PIO_EDGE_CAP(BUTTON_PIO_BASE, 0);
   /* 通知外部有中断事件发生 */
   done++;
}

/********************************************************************
* 功    能：初始化LED_PIO为输出，KEY为输入，开中断，清边沿捕获寄存器
********************************************************************/
void  InitPIO(void)
{ 
  /* 初始化LED_PIO为输出，KEY为输入 */
  IOWR_ALTERA_AVALON_PIO_DIRECTION(LED_PIO_BASE, LEDCON);
  IOWR_ALTERA_AVALON_PIO_DIRECTION(BUTTON_PIO_BASE, 0x00);
  /* 开KEY的中断 */
  IOWR_ALTERA_AVALON_PIO_IRQ_MASK(BUTTON_PIO_BASE, KEYCON);
  /* 清边沿捕获寄存器 */  
  IOWR_ALTERA_AVALON_PIO_EDGE_CAP(BUTTON_PIO_BASE, 0x00);
  /* 注册中断服务子程序 */
  alt_irq_register(BUTTON_PIO_IRQ, NULL, KeyDown_interrupts); 
}

/********************************************************************
* 功    能：等待按键中断，并输出控制相应的LED。
********************************************************************/
int  main(void)
{      
    volatile alt_u32 key_state,old_state,new_state;
    old_state = 0xff;
     alt_u8 led = 0x2;
     alt_u8 dir = 0;
     volatile int i;
    IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, old_state);//初始化LED全灭
    InitPIO();
    
    
    while(1)  
    {  
       if (led & 0x81) 
    {
      dir = (dir ^ 0x1);
    }

    if (dir) 
    {
      led = led >> 1;
    } 
    else 
    {
      led = led << 1;
    }
    IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, led);

    /* 
    * The delay element in this design has been written as a while loop
    * to avoid confusing the software debugger.  A tight, one line software
    * delay loop such as:
    *   for(i=0; i<200000; i++);
    * can cause problems when it is stepped through using a software debugger.
    * The while loop below produces the same behavior as the for loop shown 
    * above, but without causing potential debugger problems.  
    */
 
    i = 0;
    while (i<200000)
      i++;
       
       if(0 != done)
       {
          /* 中断事件数量减1 */
          done--;
          alt_busy_sleep(5000);  //延时5ms
          key_state = IORD_ALTERA_AVALON_PIO_DATA(BUTTON_PIO_BASE)&KEYCON;
          if(key_state == 0xff)   //如果是由短暂脉冲引起的中断则忽略
        	    continue;
        	
          new_state = ~(old_state ^ key_state); // 按键按下时对应的LED取反
          old_state = new_state;                // 保存LED的状态
          IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, new_state);
          usleep(2000000);
       }
    }
    return(0);
}