cho em hỏi ạ

[princedx]

#include <16F877A.h>
#include <def_877a.h>
#device *=16 adc=10
#include <string.h>
#FUSES NOWDT, HS, NOPUT, NOPROTECT, NODEBUG, NOBROWNOUT, NOLVP, NOCPD, NOWRT
#use delay(clock=4000000)
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,bi ts=8)
#include <lcd_lib_4bit1.c> // file giao tiep LCD

#define l1 RD0
#define l2 RD1
#define l3 RD2
#define l4 RD3
#define l5 RD4
#define rl1 RC0
#define rl2 RC1
//#define bt RC4

unsigned char str[60],str1[20],str2[20],str3[13];
char ch; int is1=0;
int kt,is,isti,ngat,idex,idex1,index,index1;
int32 read,temp,as; int nd;int16 high1,high,low;
int32 temp1,temp2; int isas=0;
//=============================================
#INT_RDA
Receive_isr()
{
ch = getc();
if(isti==1) //cho phep nhan khi da khoi tao thanh cong
{
if(ch==10 && index ==0) is=1; //bat dau cho phep nhan chuoi
if(ch==10 && index>0) {idex=index; ngat=1; isti = 2; } //KHI KET THUC MOT CHUOI
if(ch!=10 && ch!=13 && is == 1) { str[index] = ch; index++; }
}
if(isti==2) //cho phep nhan khi da khoi tao thanh cong
{
if(ch==10 && index1 ==0) is=1; //bat dau cho phep nhan chuoi
if(ch==10 && index1>0) {idex1=index1; ngat=2; isti = 0; } //KHI KET THUC MOT CHUOI
if(ch!=10 && ch!=13 && is == 1) { str1[index1] = ch; index1++; }
}
}
//------------
void send_sms()
{
putc('A'); putc('T'); putc('+'); putc('C'); putc('M'); putc('G'); putc('S'); putc('='); putc(34);
putc('0'); putc('9'); putc('7'); putc('5'); putc('1'); putc('9'); putc('1'); putc('4'); putc('0');
putc('9'); putc(34); putc(13); delay_ms(200);
putc(str3[0]); putc(str3[1]); putc(str3[2]); putc(str3[3]); putc(str3[4]); putc(str3[5]);
putc(str3[6]); putc(str3[7]); putc(str3[8]); putc(str3[9]); putc(str3[10]); putc(str3[11]); putc(str3[12]);putc(26); putc(13);
delay_ms(200);
putc('A'); putc('T'); putc('+'); putc('C'); putc('M'); putc('G'); putc('S'); putc('='); putc(34);
putc('0'); putc('9'); putc('3'); putc('7'); putc('7'); putc('0'); putc('5'); putc('3'); putc('7');
putc('9'); putc(34); putc(13); delay_ms(200);
putc(str3[0]); putc(str3[1]); putc(str3[2]); putc(str3[3]); putc(str3[4]); putc(str3[5]);
putc(str3[6]); putc(str3[7]); putc(str3[8]); putc(str3[9]); putc(str3[10]); putc(str3[11]); putc(str3[12]);putc(26); putc(13);
//----------------
int kiemtra()// lenh tu dt de dk role
{
int j,k;
for(j=0;j<idex;j++)
{
if(str2[0]==str[j])
{
for(k=0;k<Strlen(str2);k++)
{
if(str2[k] != str[j+k]) break;
}
if(k==strlen(str2)) { idex=0; index = 0; return 1; }
}
}
idex=0; index = 0; return 0;
}
//-------------------
int kiemtra1()
{
int j,k;
for(j=0;j<idex1;j++)
{
if(str2[0]==str1[j])
{
for(k=0;k<strlen(str2);k++)
{
if(str2[k] != str1[j+k]) break;
}
if(k==strlen(str2)) { return 1; }
}
}
return 0;
}
void chuyen(int32 x)
{
high1 = x/100;
high=(x%100)/10;
low=x%10; //chia lay phan du, so hang don vi

low = low + 0x30;
high = high + 0x30;
high1 = high1 + 0x30;
}
//-------
void nhietdothap()
{
LCD_putcmd(0x80);
Printf(LCD_putchar,"NHIET DO THAP ");
LCD_putcmd(0xC0);
Printf(LCD_putchar," SE CANH BAO");
delay_ms(500); l1 = 1; rl1 = 1; delay_ms(600); l1 = 0; delay_ms(600); l1 = 1; delay_ms(600); l1 = 0; delay_ms(600);
l1 = 1; delay_ms(600); l1 = 0; delay_ms(600);
//gui tin nhan
delay_ms(500);
isti = 0; //
strcpy(str3,"NHIET DO THAP"); send_sms();delay_ms(500);
LCD_putcmd(0xC0); Printf(LCD_putchar,"ND thap dang goi");
delay_ms(200);
puts("atd 0975191409;");
delay_ms(20000);
puts("ath");
isti = 1;
rl1 = 0;
}
void nhietdocao()
{
LCD_putcmd(0x80);
Printf(LCD_putchar,"NHIET DO CAO ");
LCD_putcmd(0xC0);
Printf(LCD_putchar," SE CANH BAO");
delay_ms(500); l5 = 1;rl1 = 1; delay_ms(600); l5 = 0; delay_ms(600); l5 = 1; delay_ms(600); l5 = 0; delay_ms(600);
l5 = 1; delay_ms(600); l5 = 0; delay_ms(600);
//gui tin nhan
delay_ms(500);
isti = 0; //
strcpy(str3,"NHIET DO CAO "); send_sms(); delay_ms(500);// day chuoi ki tu qua tap lenh sms
LCD_putcmd(0xC0); Printf(LCD_putchar,"ND cao dang goi ");
delay_ms(200);
puts("atd 0975191409;");
delay_ms(20000);
puts("ath");
isti = 1;
rl1 = 0;
}
void baoasyeu()
{
LCD_putcmd(0x80);
Printf(LCD_putchar,"DO SANG YEU ");
LCD_putcmd(0xC0);
Printf(LCD_putchar,"GUI TIN CANH BAO");
delay_ms(500); l2 = 1; rl1 = 1; delay_ms(600); l2 = 0; delay_ms(600); l2 = 1; delay_ms(600); l2 = 0; delay_ms(600);
l2 = 1; delay_ms(600); l2 = 0; delay_ms(600);
//gui tin nhan
delay_ms(500);
isti = 0; //
strcpy(str3,"DO SANG YEU "); send_sms(); delay_ms(500);
isti = 1;
rl1 = 0;
}
//===========Chuong trinh chinh================
void main()
{


//===========================================
TRISA=0xff; // Thiet lap chan vao ra
TRISB=0x00;
TRISC=0xF0;
TRISD=0x00;
TRISE=0x00;
setup_adc_ports(RA0_RA1_RA3_ANALOG);
setup_adc(ADC_CLOCK_INTERNAL);
delay_ms(50);
enable_interrupts(int_rda);
ENABLE_INTERRUPTS(GLOBAL);
delay_ms(10);
//===================
l1 = l2 = l3 = l4 = l5 = 0; rl1 = rl2 = 0;
//=====================
LCD_init();
Printf(LCD_putchar,"D_KHIEN QUA SMS ");
LCD_putcmd(0xC0);
Printf(LCD_putchar,"Dang khoi tao...");
delay_ms(1200);
while(true)
{
index = 0; is = 0; isti = 0;
puts("AT"); putc(13); isti = 1; delay_ms(300);
Printf(LCD_putchar,str);
strcpy(str2,"OK");
if(kiemtra()==1)
{
LCD_putcmd(0xC0);
Printf(LCD_putchar,"Da khoi tao xong");
puts("ATE0"); putc(13); delay_ms(100);
puts("AT+CMGF=1"); putc(13); delay_ms(300);
puts("AT+CMGD=1"); putc(13); delay_ms(300);
break;
}
delay_ms(700);
}
while(true)
{
LCD_putcmd(0x80);
Printf(LCD_putchar,"NHIET DO LA: ");
LCD_putcmd(0x8F);
Printf(LCD_putchar,"C");
set_adc_channel(0);
read=read_adc();
delay_ms(500);
temp = (int)read*500/102,3;
temp1 = (temp / 100);
temp = temp % 100;
temp2 = (temp / 10);
nd = temp1 * 10 + temp2;
LCD_putcmd(0x8D);
chuyen(nd); LCD_putchar(high); LCD_putchar(low);
LCD_putcmd(0xC0); Printf(LCD_putchar,"DO SANG: ");
set_adc_channel(1);
read=read_adc();
delay_ms(500);
temp = read*500/1023;
as = temp*2;
if(as<400)
{ chuyen(as);LCD_putcmd(0xC9); LCD_putchar(high1); LCD_putchar(high); LCD_putchar(low);
Printf(LCD_putchar," lux"); if(isas==0) { baoasyeu(); isas = 1; }
}
else
{
LCD_putcmd(0xC0); Printf(LCD_putchar,"DO SANG >400 lux"); isas = 0;
}

if(nd<20) nhietdothap(); if(nd>50) nhietdocao();
if(ngat!=0) //co tin hieu dieu khien
{
isti = 0;// bien kt tin hieu dk
LCD_putcmd(0xC0);
Printf(LCD_putchar,"Co tin hieu dk ");
strcpy(str2,"CMTI");
if(kiemtra()==1)
{
kt = 1;
while(kt<2)
{
idex = 0; idex1 = 0; index = 0; index1 = 0; ngat = 0; isti = 0; is = 0;
puts("at+cmgr=1"); putc(13); isti = 1;
while(ngat != 2) {} isti = 0;
//------------
strcpy(str2,"BATDEN");
if(kiemtra1()==1)
{
strcpy(str3,"DA BAT DEN "); send_sms(); delay_ms(300); RL2 = 1; is1 = 1; kt=2;
}
else
{
strcpy(str2,"TATDEN");
if(kiemtra1()==1)
{
strcpy(str3,"DA TAT DEN "); send_sms(); delay_ms(300); RL2 = 0; is1 = 0; kt=2;
}
}
//------------------
kt++;
if(kt==2) { strcpy(str3,"SAI CU PHAP"); send_sms(); delay_ms(300); }
puts("at+cmgd=1"); putc(13); delay_ms(800);
} //end kt < 2
} //end kt CMTI
idex = 0; idex1 = 0; index1 = 0; index = 0; ngat = 0; isti = 1; is = 0;
} //end co tin hieu dk
}
}
//========= END MAIN ==============


đoạn code trên viết cho pic với sim 300 mấy anh pro có thể giải thích cho em 2 khúc được ko ạ?
Đoạn thứ 1
Receive_isr()
{
ch = getc();
if(isti==1) //cho phep nhan khi da khoi tao thanh cong
{
if(ch==10 && index ==0) is=1; //bat dau cho phep nhan chuoi
if(ch==10 && index>0) {idex=index; ngat=1; isti = 2; } //KHI KET THUC MOT CHUOI
if(ch!=10 && ch!=13 && is == 1) { str[index] = ch; index++; }
}
if(isti==2) //cho phep nhan khi da khoi tao thanh cong
{
if(ch==10 && index1 ==0) is=1; //bat dau cho phep nhan chuoi
if(ch==10 && index1>0) {idex1=index1; ngat=2; isti = 0; } //KHI KET THUC MOT CHUOI
if(ch!=10 && ch!=13 && is == 1) { str1[index1] = ch; index1++; }
}
đoạn thứ 2:
\putc('A'); putc('T'); putc('+'); putc('C'); putc('M'); putc('G'); putc('S'); putc('='); putc(34);
putc('0'); putc('9'); putc('7'); putc('5'); putc('1'); putc('9'); putc('1'); putc('4'); putc('0');
putc('9'); putc(34); putc(13); delay_ms(200);
putc(str3[0]); putc(str3[1]); putc(str3[2]); putc(str3[3]); putc(str3[4]); putc(str3[5]);
putc(str3[6]); putc(str3[7]); putc(str3[8]); putc(str3[9]); putc(str3[10]); putc(str3[11]); putc(str3[12]);putc(26); putc(13);
mấy cái putc(34); putc(13); delay_ms(200);
putc(str3[0]); putc(str3[1]); putc(str3[2]); putc(str3[3]); putc(str3[4]); putc(str3[5]);
putc(str3[6]); putc(str3[7]); putc(str3[8]); putc(str3[9]); putc(str3[10]); putc(str3[11]); putc(str3[12]);putc(26); putc(13);
có nghĩa là gì vậy ạ?