NiosII的范例

				7个范例程序的测试结果
				1、字符模式设备范例.txt 
				--上位机串口波特率115200,在硬件上全速运行程序后控制台收到:
				This application will printf 'Hello world' to uart1!
				串口上收到:
				hello world
				
				2、Alarm范例.txt  
				--在my_alarm_callback()函数return前,加入了一条printf("CallCounter's Value is %d!\n",CallCounter);，在硬件上全速运行程序后收到:
				CallCounter's Value is 1!
				
				3、ISR范例.txt
				--在硬件上全速运行程序后收到:
				ISR Demo!
				Timer interrupt has occurred for: 0 times
				Timer interrupt has occurred for: 1 times
				Timer interrupt has occurred for: 2 times
				Timer interrupt has occurred for: 3 times
				…………
				
				4、HighResTimer范例.txt
				--在硬件上全速运行程序后收到:
				Elapsed time in func1 = 993 us
				Elapsed time in func1 = 4830 us
				
				5、DMA范例.txt
				--在SOPC Builder中建一个RAM型On-chip_memory命名为onchip_RAM_4K(也可取其它名)，建一个DMA命名为dma，将dma的read_master、write_master与onchip_RAM_4K连接.在硬件上全速运行程序后收到:
				DMA Demo(Memory to Memory)!
				Create the transmit channel successfully!
				Create the receive channel successfully!
				Post the transmit request successfully!
				Post the receive request successfully!
				
				6、Simple Flash Access驱动范例.txt
				--在硬件上全速运行程序后收到:
				Simple Flash Access Demo.
				Open Flash Device Successfully.
				Write Flash Device Successfully.
				Read Flash Device Successfully.
				Verify Successfully!
				
				7、Fine-gained Flash Access驱动范例.txt
				--在硬件上全速运行程序后收到:
				Fine-gained Flash Access Demo.
				Open Flash Device Successfully.
				Erase Flash Device Successfully.
				Write Flash Device Successfully.
				Read Flash Device Successfully.
				Verify Successfully!
				
				Alarm范例程序经过修改之后，可以看到重复进my_alarm_callback()函数了
				控制台显示结果为:
				my_alarm_callback has been called for: 0 times
				my_alarm_callback has been called for: 1 times
				my_alarm_callback has been called for: 2 times
				my_alarm_callback has been called for: 3 times
				my_alarm_callback has been called for: 4 times
				…………
				
				/*
				* 一、功能: Alarm演示代码修改版.
				* 
				* 二、相关说明：
				*    由于NiosII IDE的ISS(Instruction Set Simulation)支持JTAG_UART和定时
				*    器的仿真功能,所以该源码可以运行在ISS模式下,而无须任何硬件开发板的支持.
				* 
				* 三、运行前提:
				*    1. 选择包含JTAG_UART和具有周期中断功能的定时器的NiosII系统(ptf文件);
				*    2. 在系统库属性中完成下面的配置:
				*        (1) 将stdout映射到JTAG_UART;
				*        (2) 将具有周期中断功能的定时器映射为系统时钟;
				* 
				*/
				#include 
				#include "sys/alt_alarm.h"
				#include "alt_types.h"
				
				//定义my_alarm_callback函数的重复调用周期
				//INTEVAL_TICK不能太大,因为ISS对定时器的仿真需要很长的时间,这里取1即可
				//在SOPC Builder中对定时器周期的设定也不要太大,1ms即可
				#define INTEVAL_TICK 1 //单位:系统时钟周期
				
				//定义全局静态变量对my_alarm_callback的被调用次数进行计数;
				static int CalledCounter = 0;
				/* 定义欲注册为Alarm的callback函数; */
				alt_u32 my_alarm_callback (void* context)
				{
				  CalledCounter++;
				
				  //返回值决定在返回后的多少个系统时钟周期后,my_alarm_callback函数再次被调用;
				  return INTEVAL_TICK;
				}
				
				int main()
				{
				  //在注册alarm之前,必须先定义一个alt_alarm类型的变量(无须初始化),
				  //并将它作为alarm注册函数alt_alarm_start的输入参数;
				  static alt_alarm alarm;
				  //当alt_alarm_start注册成功时返回0,否则返回负数;
				  if(  
				      alt_alarm_start(&alarm,
				                      INTEVAL_TICK,
				                      my_alarm_callback,
				                      NULL
				                      ) < 0
				    )
				    {
				      printf ("No system clock available\n" ) ;
				    }
				    
				  //将my_alarm_callback的被调用次数由stdout设备输出          
				  printf("my_alarm_callback has been called for: %d times\n", CalledCounter) ;
				  int Old_Value = CalledCounter;
				  for( ; ; )
				  {
				    if(Old_Value != CalledCounter)
				    {
				      Old_Value = CalledCounter;
				      printf("my_alarm_callback has been called for: %d times\n", Old_Value);
				    }
				  }  
				}