10473f393b2e001e1d49a4c70fa2aa82

alter FPGA

/*
 * "Hello World" example.
 *
 * This example prints 'Hello from Nios II' to the STDOUT stream. It runs on
 * the Nios II 'standard', 'full_featured', 'fast', and 'low_cost' example
 * designs. It runs with or without the MicroC/OS-II RTOS and requires a STDOUT
 * device in your system's hardware.
 * The memory footprint of this hosted application is ~69 kbytes by default
 * using the standard reference design.
 *
 * For a reduced footprint version of this template, and an explanation of how
 * to reduce the memory footprint for a given application, see the
 * "small_hello_world" template.
 *
 */

#include <stdio.h>

#include "system.h"
#include "altera_avalon_pio_regs.h"
#include "alt_types.h"
#include "sys/alt_irq.h"
#include "altera_avalon_timer_regs.h"

#define alt_cpu_freq 50000000

  /* 
   * Use alt_main as entry point for this free-standing application
   */
   int count = 0;
   int led = 0;
   //volatile alt_u8 count;


static void handle_Timer0_interrupts(void* context, alt_u32 id)
{
    alt_u8 a;
    volatile alt_u8 *countptr = (volatile alt_u8 *)context;
    IOWR_ALTERA_AVALON_TIMER_STATUS(TIMER_0_BASE, 0);//清TO标志
    a = *countptr; //取出count中的值
    a=a<<1; //作移一位
    if (a == 0x10) a=1; //我只有4个led,所以要让led循环闪烁
    *countptr=a; //重新赋值给count
    //IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, a); //写到LED输出口
    printf("Value shift! (%d)\n", a);
}

   
static void USER_IRQ(void* context,alt_u32 id)
{
  IOWR_ALTERA_AVALON_TIMER_STATUS(TIMER_0_BASE,0);//清除定时器状态寄存器。
  if(led == 0xff)
  {
    led = 0x00;
  }
  else
  {
    led = 0xff;
  }
  IOWR_ALTERA_AVALON_PIO_DATA(PIO_0_BASE, led);
  if (count == 0xff)
   {
    count = 0;
  }
  else
  {
    count++;
  }
  printf("One second passed! (%d)\n", count);
}




int main (void)
{
  //********************************************************
  /*count=1;
  alt_irq_register( TIMER_0_IRQ, (void *)&count, handle_Timer0_interrupts); //注册中断函数
  
  
  //因为我在添加定时器timer_0的时候，设置了初始值为 定时周期500ms的值，我的晶振是50Mhz,
  //因为只是简单测试一下定时中断代码的书写方法，所以这里没有重新设置预制值，直接采用初始化时自动
  //设置的初始值，当然，也是我懒得去计算初始值，如果要重新设置为不同的定时周期，用下面的2个函数
  // IOWR_ALTERA_AVALON_TIMER_PERIODL(TIMER_0_BASE, TimerValueLow);
  // IOWR_ALTERA_AVALON_TIMER_PERIODH(TIMER_0_BASE, TimerValueHigh);
  // 其中TimerValueLow和TimerValueHigh是你要设置的低16位和高16位的定时器初值。
  //定时器工作时是将这2个寄存器的值调入32位计数器，然后根据CPU的时钟，逐步递减计数器
  //的值，直到减到0为止，然后触发中断，并且再次从预制寄存器中将预制值调入32位计数器中,
  //再次重复【递减->到0->中断&重新装载初值 】的这个过程
  IOWR_ALTERA_AVALON_TIMER_PERIODL(TIMER_0_BASE,0xF080);//定义定时器的计数周期；
  IOWR_ALTERA_AVALON_TIMER_PERIODH(TIMER_0_BASE,0x02FA);
  IOWR_ALTERA_AVALON_TIMER_CONTROL(TIMER_0_BASE, 7); //启动timer允许中断，连续计数
  
  
  while (1) {;}
  */
  //********************************************************
  //********************************************************
  /*volatile unsigned long timer_capture;
  IOWR_ALTERA_AVALON_TIMER_PERIODL(TIMER_0_BASE,0xF080);//定义定时器的计数周期；
  IOWR_ALTERA_AVALON_TIMER_PERIODH(TIMER_0_BASE,0x02FA);
  IOWR_ALTERA_AVALON_TIMER_CONTROL(TIMER_0_BASE,0x0007);//写定时器的控制寄存器；
  //while(1)
  {
    alt_irq_register( TIMER_0_IRQ, (void*)timer_capture, USER_IRQ );//中断注册函数
  }
  while(1){}*/
  //********************************************************
  /*
  alt_u8 led = 0x0;
  int t = 0;
  IOWR_ALTERA_AVALON_TIMER_PERIODL(TIMER_0_BASE, (short)(alt_cpu_freq&0x0000ffff));
  IOWR_ALTERA_AVALON_TIMER_PERIODH(TIMER_0_BASE, (short)((alt_cpu_freq>>16)&0x0000ffff));
  IOWR_ALTERA_AVALON_TIMER_CONTROL(TIMER_0_BASE,
                        ALTERA_AVALON_TIMER_CONTROL_START_MSK + ALTERA_AVALON_TIMER_CONTROL_CONT_MSK);
  
  while(1)
  {
    if(IORD_ALTERA_AVALON_TIMER_STATUS(TIMER_0_BASE) & ALTERA_AVALON_TIMER_STATUS_TO_MSK)
    {
      printf("One second passed! (%d)\n", t++);
      IOWR_ALTERA_AVALON_TIMER_STATUS(TIMER_0_BASE, 0x0);
      if(led == 0xff)
      {
        led = 0x00;
      }
      else
      {
        led = 0xff;
      }
      IOWR_ALTERA_AVALON_PIO_DATA(PIO_0_BASE, led);
    }
      
  }
  */
  while(1)
  {    
    led = 0x00;
    count = 0;
    while(count < 0x50000)
    {
      count++;
    }      
    IOWR_ALTERA_AVALON_PIO_DATA(PIO_0_BASE, led);
    led = 0xff;
    count = 0;
    while(count < 0x50000)
    {
      count++;
    }      
    IOWR_ALTERA_AVALON_PIO_DATA(PIO_0_BASE, led);
  }

  return 0;
}