一个PIC单片机AD采样的程序没给注释，有些不懂，请教大神红字部分

ID:306032 · 发表于 2018-10-24 10:58

论坛里大神用pic18f4520写的8路AD采样，没给注释，新手有些地方看不太懂，请教大神！
请问红字部分是什么意思，实现的什么功能？
谢谢！
//******Multi_ADChannel converter**********//
#include <pic18.h>

__PROG_CONFIG(1,0xc200);
__PROG_CONFIG(2,0x0a16);
__PROG_CONFIG(3,0x8100);
__PROG_CONFIG(4,0x0081);
__PROG_CONFIG(5,0xc00f);
__PROG_CONFIG(6,0xe00f);
__PROG_CONFIG(7,0x400f);

#define uchar unsigned char
#define uint  unsigned int
uchar temp;
void multi_convertor(void);
void port_check(void);

uint ADbuf[10];
void delay_ms(uint t)
{
uint m,n;
for (m=0;m<t; m++)
   for (n=0; n<1140;n++);
}

void GPIO_Init(void)
{
  TRISA=0xff;
  TRISB=0xff;
  TRISC=0xff;
  TRISD=0xff;
  TRISE=0xff;
  PSPMODE=0;
  PSPIE=0;
  PSPIP=0;

  TRISBbits.RB2 =1;                //set direction of RB2 to be An input;
  TRISBbits.RB3 =1;                //set direction of RB3 to be An input;

}

void ADC_Init(void)
{
  ADCON1 = 0x05;                //seting AN0~AN9 to be analog input;
  ADCON2 = 0xBE;                //20TAD,FOSC/64 and right justified;
}

void timer0_init(void)
{
  INTCON =0xE0;//GIE,PEIE,TMR0IE to set;
  T0CON = 0x1F;// timer0 to be 16-bit;
  TMR0H = (65536-1000)/256;
  TMR0L = (65536-1000)%256;
  T0CON |=0x80;
  TMR0ON=1;
}

void EUART_init(void)
{
  TRISC7=1;
  TRISC6=1;
  SPBRG=0x40;
  TXSTA=0x24;
  RCSTA=0x90;
  RCIE=0;
  TXIE=0;
  PEIE=1;
  GIE=1;

}

void transmit_udata(uchar udata)
{
TXREG=udata;
while(!TRMT);
}

uchar receive_udata(void)
{
uchar temp;
if (RCIF==1)
{
   temp=RCREG;
}
return temp;

}
uint data_average(uint buffer[30])
{
  uchar i,j;
  uint temp;
  float temp1;
  for(i=1; i<30; i++)
  for(j=29; j>=i; --j)
  {
if(buffer[j-1] > buffer[j])
{
temp = buffer[j-1];
buffer[j-1] = buffer[j];
buffer[j] = temp;
}
  }

temp1 = 0;
for(i=5; i<25; i++)
{
  temp1 += buffer[ i];
}
temp = (uint)(((float)temp1) / 20 + 0.5);

return(temp);
}

void main(void)
{
  EUART_init();
  GPIO_Init();
  ADC_Init();
  timer0_init();
  while(1)
{
   temp=receive_udata();
   if (temp==0x01)
   {
      temp=0;
      port_check();
      multi_convertor();

   }
}
}
void port_check(void)
{
uchar num1, num2;

num1=PORTD;
num2=PORTB&0X03;
transmit_udata(num2);
transmit_udata(num1);
}

void multi_convertor(void)
{
uchar data1,data2,i;
static uchar ADC_channel=0;
uint adc[30]={0};
   // ADC_channel++;
   for (ADC_channel=0; ADC_channel<10; ADC_channel++)
      {

            switch(ADC_channel)
            {
                     case 0: ADCON0=0x01;break;//AN0 channel;
                     case 1: ADCON0=0x05;break;//AN1 channel;
                     case 2: ADCON0=0x09;break;//AN2 channel;
                     case 3: ADCON0=0x0D;break;//AN3 channel;
                     case 4: ADCON0=0x11;break;//AN4 channel;
                     case 5: ADCON0=0x15;break;//AN5 channel;
                     case 6: ADCON0=0x19;break;//AN6 channel;
                     case 7: ADCON0=0x1D;break;//AN7 channel;
                     case 8: ADCON0=0x21;break;//AN8 channel;
                     case 9: ADCON0=0x25;break;//AN9 channel;
                     default:break;
            }

                  for(i=0;i<30;i++)
                     {
                        ADCON0 |=0x01;
                        asm("NOP");
                        asm("NOP");
                        GODONE=1;
                        while(GODONE);
                        adc[ i]=(ADRESH*256)+ADRESL;

                     }
                     ADbuf[ADC_channel]=data_average(adc);
                     data1=ADbuf[ADC_channel]/255;
                     data2=ADbuf[ADC_channel]%255;
                     transmit_udata(data1);
                     transmit_udata(data2);

      }
}