demo_10_3.c

Chip type : ATmega16L Program type : Application Clock frequency : 4.000000 M

/*****************************************************
File name			: demo_10_3.c
Chip type           : ATmega16L
Program type        : Application
Clock frequency     : 4.000000 MHz
Memory model        : Small
External SRAM size  : 0
Data Stack size     : 256
*****************************************************/

#include <mega16.h>

flash unsigned char led_7[10]={0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,0x7F,0x6F};
flash unsigned char position[6]={0xfe,0xfd,0xfb,0xf7};

unsigned char dis_buff[4]={0,0,0,0},posit;
bit time_2ms_ok;

// ADC电压值送显示缓冲区函数
void adc_to_disbuffer(unsigned int adc)		
{
	unsigned char i;
	for (i=0;i<=3;i++)
	{
		dis_buff[i]=adc%10;
		adc /= 10; 
	}
}

// Timer 0 比较匹配中断服务
interrupt [TIM0_COMP] void timer0_comp_isr(void)
{
	time_2ms_ok = 1;
}

// ADC 转换完成中断服务
interrupt [ADC_INT] void adc_isr(void)
{   
    unsigned int adc_data,adc_v;
    adc_data=ADCW;                  //读取ADC置换结果                  
    adc_v=(unsigned long)adc_data*5000/1024;    //换算成电压值
    adc_to_disbuffer(adc_v);
}

void display(void)	// 4位LED数码管动态扫描函数
{
    PORTA |= 0x0f;	
	PORTC = led_7[dis_buff[posit]]; 
	if (posit==3) PORTC |= 0x80;
	PORTA &= position[posit]; 
	if (++posit >=4 ) posit = 0;
}

void main(void)
{
	DDRA=0x0f;
	PORTA=0x0f;				
	DDRC=0xff;      // LED显示控制I/O端口初始化
	PORTC=0x00;
	// T/C0 初始化
	TCCR0=0x0B;     // 内部时钟，64分频（4M/64=62.5KHz），CTC模式
	TCNT0=0x00;     
	OCR0=0x7C;      // OCR0 = 0x7C(124),(124+1)/62.5=2ms
	TIMSK=0x02;     // 允许T/C0比较中断

    // ADC 初始化
    ADMUX=0x47;     // 参考电源AVcc、ADC7单端输入
    SFIOR&=0x1F;    
    SFIOR|=0x60;    // 选择T/C0比较匹配中断为ADC触发源
    ADCSRA=0xAD;    // ADC允许、自动触发转换、ADC转换中断允许、ADCclk=125Kz
 
    #asm("sei")     // 开放全局中断

    while (1)
    {
        if (time_2ms_ok)
        {
        	display();  	// LED扫描显示        
            time_2ms_ok = 0;
        }
    }
}