test.c

针对多路视频远程无线传输问题

//ICC-AVR application builder : 2006-3-22 10:22:28
// Target : M8
// Crystal: 11.059Mhz

#include <iom8v.h>
#include <macros.h>
//#include <stddef.h>

unsigned char ICP_Flag;		  //ICP捕捉状态标记标量
unsigned int ICP_value_down;  //ICP捕捉计数值记录变量
unsigned char state;		  //通道状态标记变量

//利用宏定义组织各个频道的切换操作
#define LED1_ON()     PORTD=0x01;PORTC = 0x00;PORTC=0x01;
#define LED2_ON()     PORTD=0x02;PORTC = 0x00;PORTC=0x02;
#define LED3_ON()     PORTD=0x04;PORTC = 0x00;PORTC=0x04;
#define LED4_ON()     PORTD=0x08;PORTC = 0x00;PORTC=0x08;

void port_init(void)
{	 //mega8的IO管脚初始化
 PORTB = 0x00;
 DDRB  = 0x00;
 PORTC = 0x00; //m103 output only
 DDRC  = 0x0F;
 PORTD = 0x00;
 DDRD  = 0x0F;
}

//TIMER1 initialize - prescale:Stop
// WGM: 0) Normal, TOP=0xFFFF
// desired value: 1Hz
// actual value: Out of range
void timer1_init(void)
{	 //1号定时器初始化
 TCCR1B = 0x00; //stop
 TCNT1H = 0x00 /*INVALID SETTING*/; //setup
 TCNT1L = 0x00 /*INVALID SETTING*/;
 OCR1AH = 0x00 /*INVALID SETTING*/;
 OCR1AL = 0x00 /*INVALID SETTING*/;
 OCR1BH = 0x00 /*INVALID SETTING*/;
 OCR1BL = 0x00 /*INVALID SETTING*/;
 ICR1H  = 0x00 /*INVALID SETTING*/;
 ICR1L  = 0x00 /*INVALID SETTING*/;
 TCCR1A = 0x00;
 TCCR1B = 0xC0; //start Timer
}

///////////////////////////////////////延时程序
void delay_s(char x)   
{	 //定时x秒延时
int i;
int j;
while(x--)
{
for(i=0;i<500;i++)
  {
  for(j=0;j<1000;j++)
  ;
  }
}
}
//////////////////////////////////////

void VideoSwitch(unsigned int Counter)	   //根据捕捉计数值切换视频通道
{
     if(Counter>0x0D7E)
	    {   //捕捉到的一个脉宽超过2.5ms，可能是漏掉了一个脉宽信号，不做动作 										  
		    return;
		}
	 
 	 if(Counter<0x0818)
	 	{	//0.5~1.5ms  低脉宽，按键未被按下的状态
		 	; 
		}
		else
		{ //1.5ms~2.5ms	 长脉宽，按键被按下，进行频道切换
		  if(state > 1)	 //实现状态标记仅在0、1之间变换
		     state = 0;

		   //根据state进行相应的频道切换操作
		   switch(state)
		   {
		   	   case 0:
			       LED2_ON();
				   break;
			   case 1:
			       LED4_ON();
				   break;
		   }
		   state++;
		   delay_s(4);	 //切换完毕延时4s，避免按键时间过长产生频道频繁切换
           return;   
		}
}

#pragma interrupt_handler timer1_ovf_isr:9
void timer1_ovf_isr(void)
{	 //1号定时器溢出，则回复到初始状态等待上升沿捕捉
 //TIMER1 has overflowed
 TCNT1H = 0x00 /*INVALID SETTING*/; //reload counter high value
 TCNT1L = 0x00 /*INVALID SETTING*/; //reload counter low value
 TCCR1B |= 0xc0;  //回到等待上升沿的状态
}

#pragma interrupt_handler timer1_capt_isr:6
void timer1_capt_isr(void)
{
 //timer 1 input capture event, read (int)value in ICR1 using;
 // value=ICR1L;            //Read low byte first (important)
 // value|=(int)ICR1H << 8; //Read high byte and shift into top byte
 	switch(ICP_Flag)//根据状态值判断捕捉到的是什么跳变信号
	 {
 	  	case 1://0x40://捕捉到上升沿
			 TCNT1H = 0x00; //reload counter high value
			 TCNT1L = 0x00; //reload counter low value
			 TCCR1B &= 0xBF; //ICES1->0,转为捕捉下降沿
			 TCCR1B |= 0x82;	//开捕捉，开启定时器,8分频
			 ICP_Flag = 0;
			 break;
		
		case 0://0x00://捕捉到下降沿
			 TCCR1B &= 0xf8; //关闭定时器
			 ICP_value_down = ICR1L;//Read low byte first (important)
			 ICP_value_down |= (int)ICR1H << 8; //Read high byte and shift into top byte
			 VideoSwitch(ICP_value_down);
			 TCCR1B |= 0x40; //ICES1->1完成一个正脉宽捕捉,回到等待上升沿的状态
			 ICP_Flag = 1;
			 break;
 	 }
}

//call this routine to initialize all peripherals
void init_devices(void)
{
 //stop errant interrupts until set up
 CLI(); //disable all interrupts
 port_init();
 timer1_init();

 MCUCR = 0x00;
 GICR  = 0x00;
 TIMSK = 0x24; //timer interrupt sources
 SEI(); //re-enable interrupts
 //all peripherals are now initialized
}

void main()
{
 	 init_devices();
	 state = 0;
	 ICP_value_down = 0;
	 
	 //初始默认为4频道连通
	 PORTD = 0x08;
	 PORTC = 0x08;
	 while(1)
	 {
	  ;
	 }
}