Please help about sensors as input in PIC16F877A

UyAb · Mar 11, 2013

I have an IR sensor..
I want it to be an input to my microcontroller..
How would I write the codes if my sensor is in PortA and my output is in PortC?

speedEC · Mar 11, 2013

Compiler? Sensor - Analog - Digital? If analog, connect it to Analog channel (PORTA), setting ADC, and read ADC.

For example (this is for PIC16F1827):

main(){

//initiate ADC:

Setting PORT A bits as Analog Inputs (if Sensor Outputs connected to RA0, RA1 AND RA2):

TRISA = 0b00000111;

// setting ANSEL
ANSELA = 0b00000111;

init_ADC();

int val_X_Initial = read_ADC(0); //Read Channel 0 (AN0/RA0)
int val_Y_Initial = read_ADC(1); //Read Channel 1 (AN1/RA1)
int val_Z_Initial = read_ADC(2); //Read Channel 2 (AN2/RA2)

}
void init_ADC(){

ADCS0 = 1; // ADCS<1:0>: A/D Conversion Clock Select bits when ADCS2 = 0;
ADCS1 = 0; // 01 = FOSC/8

ADCON1 = 0b10100000; // bit 0 - 3 -> undefined
// bit 4-5 -> 10 -> voltage ref is +Vref and Vss (VCFG0& VCFG1)
// bit 6 -> 0 -> A/D clock divide by 2 is disabled (ADCS2 = 0)
// bit 7 -> 1 -> ADFM -> result format -> right justified

ADON = 1; // Turn A/D on

__delay_us(20); // delay 20 usec to settle A/D acquisition

}

unsigned int read_ADC(unsigned char channel_ADC){

__delay_us(20); // time interval required between two Consecutive ADC channel reads

if (channel_ADC == 0){ // X - direction
CHS2 = 0; // CHS<2:0>: (000) Analog Channel Select bits; Channel 0 (RA0/AN0)
CHS1 = 0;
CHS0 = 0;
}

if (channel_ADC == 1){ // Y - direction
CHS2 = 0; // CHS<2:0>: (001) Analog Channel Select bits; Channel 1 (RA1/AN1)
CHS1 = 0;
CHS0 = 1;
}

if (channel_ADC == 2){ // Z - direction
CHS2 = 0; // CHS<2:0>: (010) Analog Channel Select bits; Channel 2 (RA2/AN2)
CHS1 = 1;
CHS0 = 0;
}

ADGO = 1; // Start conversion

while ( ADGO ); // wait for ADGO to go off signalling end of conversion

//return (ADRESH);
return (((unsigned int)ADRESH)<<8)|(ADRESL); // 10 bit resolution - 1024 steps
}

Hope this help.

UyAb · Mar 15, 2013

i"m using MicroC 8.1.
But I can't understand the codings.
by d way here is my codes..
can you help me finish this?
one of my problem is..the timer goes like this..1:23,1:22,1:21,1:20,1:13,1:12..
it always goes back to it's initial value..

Code:

char message1[]="INSERT BARCODE";
char message2[]="WELCOME USER";
char message3[]="Enter Time(Hr/s)";
char message4[]="CLASSROOM";
char message5[]="POWER CONTROL";
char message6[]="Press * or #";
char message7[]="*:Start #:Cancel";
unsigned short kp;
char code[3],code1[1];
short i=0,h=0,m2=0,m1=0;
unsigned int delay=60000;
void enter_hours()
{
     kp=0; //reset key code variable
       do
       kp= Keypad_Released();  //store key code in variable
       while (!kp);     //prepare value for output,transform key to it's ASCII value
       switch(kp)
       {
        case 1: kp=49;break; //1
        case 2: kp=50;break; //2
        case 3: kp=51;break; //3
        case 5: kp=52;break; //4
        case 6: kp=53;break; //5
        case 7: kp=54;break; //6
        case 9: kp=55;break; //7
        case 10: kp=56;break;//8
        case 11: kp=57;break;//9
        case 14: kp=48;break;//0
       }
     code[i]=kp;
     Lcd_Chr(2,i+1,code[i]);
     Lcd_Chr_Cp(':');
     i++;
}
void enter_min10s()
{
     kp=0; //reset key code variable
       do
       kp= Keypad_Released();  //store key code in variable
       while (!kp);     //prepare value for output,transform key to it's ASCII value
       switch(kp)
       {
        case 1: kp=49;break; //1
        case 2: kp=50;break; //2
        case 3: kp=51;break; //3
        case 5: kp=52;break; //4
        case 6: kp=53;break; //5
        case 14: kp=48;break;//0
       }
     code[i]=kp;
     Lcd_Chr(2,3,code[i]);
     i++;
}
void enter_min1s()
{
     kp=0; //reset key code variable
       do
       kp= Keypad_Released();  //store key code in variable
       while (!kp);     //prepare value for output,transform key to it's ASCII value
       switch(kp)
       {
        case 1: kp=49;break; //1
        case 2: kp=50;break; //2
        case 3: kp=51;break; //3
        case 5: kp=52;break; //4
        case 6: kp=53;break; //5
        case 7: kp=54;break; //6
        case 9: kp=55;break; //7
        case 10: kp=56;break;//8
        case 11: kp=57;break;//9
        case 14: kp=48;break;//0
       }
     code[i]=kp;
     Lcd_Chr(2,4,code[i]);
     i++;
}
void select()
{
     kp=0; //reset key code variable
       do
       kp= Keypad_Released();  //store key code in variable
       while (!kp);     //prepare value for output,transform key to it's ASCII value
       switch(kp)
       {
        case 13: kp=42;break;//*
        case 15: kp=35;break;//#
       }
     code1[i]=kp;
}
void input_time()
{
 Lcd_Cmd(Lcd_Clear);
   Lcd_Out(1,1,message3);
   enter_hours();
   enter_min10s();
   enter_min1s();
   delay_ms(500);
}
void display_time()
{
 Lcd_Chr(2,8,h+48);
 Lcd_Chr(2,9,':');
 Lcd_Chr(2,10,m2+48);
 Lcd_Chr(2,11,m1+48);
}
void buzzer()
{PORTC.F7=1;
delay_ms(10000);
}
void countdown_timer()
{
 Lcd_Cmd(Lcd_Clear);
 Lcd_Out(1,1,"Time Left:");
 Lcd_Out(2,14,"H:M");
 for(h=code[0]-48;h>-1;h--)
 {display_time();
   for(m2=code[1]-48;m2>-1;m2--)
   {display_time();
     for(m1=code[2]-48;m1>-1;m1--)
     {display_time();
      delay_ms(1000);
     }
   }
 }
}

void main()
{ADCON1=1;
 TRISA=1;
 TRISC=0;
 PORTA=0;
 PORTC=0;
 Keypad_Init(&PORTD);
 Lcd_Init(&PORTB);
 
 Preload:
 Lcd_Cmd(Lcd_Clear);
 Lcd_Cmd(Lcd_Cursor_Off);
 Lcd_Out(1,2,message1);
 delay_ms(3000);
 {
  do
   {PORTA=0;
    if(PORTA.F2==1&&PORTA.F3==1&&PORTA.F4==1)goto Start
   }while(1);
 }

 Start:
 Lcd_Cmd(Lcd_clear);
 Lcd_Out(1,2,message2);
 delay_ms(2000);
 input_time();
 Lcd_Cmd(Lcd_clear);
 Lcd_Out(1,1,message6);
 Lcd_Out(2,1,message7);
 {
  do
  {
   i=0;
   select();
   if(code1[0]==42)goto Start1
   if(code1[0]==35)goto Start
  }while(1);
 }

 Start1:
 Lcd_Cmd(Lcd_Clear);
 Lcd_Out(1,4,message4);
 Lcd_Out(2,2,message5);
 delay_ms(1500);
 countdown_timer();
 buzzer();
}

ragav4456 · Mar 15, 2013

IR sensor output is high 5v or low 0v (digital).

**broken link removed**

jayanth.devarayanadurga · Mar 15, 2013

Code C - [expand]
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unsigned int seconds = 0;
unsigned char strSec[5];
 
void main() {
 
    while(1) {
 
        //Decrement seconds
        seconds--;
        strSec[0] = seconds/100 + 48;
        strSec[1] = (seconds/10)%10 + 48;
        strSec[2] = (seconds/1)%10 + 48;
        strSec[3] = '\0';
        //send strSec to lcd display function as argument.  
 
 
    }
 
}

UyAb · Mar 18, 2013

thank you so much sir for your help..
It really help me a lot..
now I can Graduate in Engineering

osamahameed90 · Apr 5, 2013

please tell me about a good book to learn pic16877a programming, i am good in programming of 8051 but dont know about pic16f877a

JohannP · Apr 6, 2013

Check out for "Nigel's Pic Tutor" at www.winpicprog.co.uk

A real gold mine for a PIC student.

Best regards
Johann

Please help about sensors as input in PIC16F877A

UyAb

Junior Member level 2

speedEC

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UyAb

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ragav4456

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jayanth.devarayanadurga

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UyAb

UyAb

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osamahameed90

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JohannP

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