nios II--实验5——定时器软件部分

/*

* "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 "system.h"

#include "altera_avalon_pio_regs.h"

#include "altera_avalon_timer_regs.h"

#include "alt_types.h"

#include "sys/alt_irq.h"

#include <stdio.h>

#include <unistd.h>

#include <io.h>

#include <string.h>

/********************************

variables

********************************/

void init_timer(void);

int i = 0, j = 0, flag;

alt_u32 timer_prd[4] = {5000000, 10000000, 50000000, 100000000};

// 这四个是定时器的时钟数，定时时间=定时器的时钟数/定时器的时钟周期

// 该实验中系统时钟为 50MHz，则上述定时时间为{0.1s,0.2s,1s,2s}

/*

*================================functions================================

Name: main

Description:

*=========================================================================

*/

int main(void)

{

????init_timer(); // 初始化定时器

????while(1);

????return 0;

}

/*

*================================functions================================

Name: ????????ISR_handle_time1

Description:

*=========================================================================

*/

void ISR_handle_timer1(void *context)

{

????// 控制 4 个流水灯闪烁

????IOWR_ALTERA_AVALON_PIO_DATA( LED_PIO_BASE, 1<<i );

????i++;

????if( 4 == i )

????i = 0;

????// 清除中断标志寄存器

????IOWR_ALTERA_AVALON_TIMER_STATUS( TIMER_0_BASE, 0x0 );

}

/*

*================================functions================================

Name: ????????????ISR_handle_timer2

Description: ????通过定时器 2 来改变定时器 1 的周期，改变后需要重启定时器

*=========================================================================

*/

void ISR_handle_timer2(void *context)

{

????// 改变定时器 1 的周期

????IOWR_ALTERA_AVALON_TIMER_PERIODL( TIMER_0_BASE, timer_prd[j] );

????IOWR_ALTERA_AVALON_TIMER_PERIODH( TIMER_0_BASE, timer_prd[j]>>16 );

????// 重启定时器 1

????IOWR_ALTERA_AVALON_TIMER_CONTROL( TIMER_0_BASE, 0x07 );

????// 闪烁频率先高后低然后又变高

????if( 0 == j )

????flag = 0;

????if( 3 == j )

????flag = 1;

????if( 0 == flag )

????j++;

????else

????j--;

????// 清除中断标志寄存器

????IOWR_ALTERA_AVALON_TIMER_STATUS( TIMER_1_BASE, 0x0 );

}

/*

*================================functions================================

Name: ????????????init_timer

Description: ????定时器初始化

*=========================================================================

*/

void init_timer(void)

{

????// timer1

????// 清除中断标志寄存器

????IOWR_ALTERA_AVALON_TIMER_STATUS( TIMER_0_BASE, 0x00 );

????// 设置定时周期 2s，输入的是时钟周期数

????IOWR_ALTERA_AVALON_TIMER_PERIODL( TIMER_0_BASE, 10000000 );

????IOWR_ALTERA_AVALON_TIMER_PERIODH( TIMER_0_BASE, 10000000>>16 );

????IOWR_ALTERA_AVALON_TIMER_CONTROL( TIMER_0_BASE, 0x07 ); // 使能中断

????alt_ic_isr_register( TIMER_0_IRQ_INTERRUPT_CONTROLLER_ID,

????TIMER_0_IRQ, ISR_handle_timer1, NULL, 0x0 ); // 注册中断

????// timer2

????// 清除中断标志寄存器

????IOWR_ALTERA_AVALON_TIMER_STATUS( TIMER_1_BASE, 0x00 );

????// 设置定时周期 10s，输入的是时钟周期数

????IOWR_ALTERA_AVALON_TIMER_PERIODL( TIMER_1_BASE, 50000000 );

????IOWR_ALTERA_AVALON_TIMER_PERIODH( TIMER_1_BASE, 50000000>>16 );

????IOWR_ALTERA_AVALON_TIMER_CONTROL( TIMER_1_BASE, 0x07 ); // 使能中断

????alt_ic_isr_register( TIMER_1_IRQ_INTERRUPT_CONTROLLER_ID,

????TIMER_1_IRQ, ISR_handle_timer2, NULL, 0x0 ); // 注册中断

}