USING TIMER0 AS A COUNTER

[mohdismiaswaly]

Hello,

Please check my schematic simulation using Proteus.
Switch is toggle ON 3 times so that the LED will ON. After that, the PIC will start again to count 3 times of the switch.

The code is as below, any comment? The simulation is not working

CODE: SELECT_ALL_CODE

#include <htc.h>


#pragma   config FOSC = HS         // HS oscillator
#pragma   config FCMEM = OFF         // Fail-Safe Clock Monitor disabled
#pragma   config IESO = OFF         // Oscillator Switchover mode disabled
#pragma   config PWRT = OFF         // PWRT disabled
#pragma   config BOREN = OFF         // Brown-out Reset disabled in hardware and software
#pragma   config WDT = OFF         // WDT disabled (control is placed on the SWDTEN bit)
#pragma   config MCLRE = ON         // MCLR pin enabled; RE3 input pin disabled
#pragma   config PBADEN = OFF         // PORTB<4:0> pins are configured as digital I/O on Reset
#pragma   config CCP2MX = ON          // CCP2 input/output is multiplexed with RC1
#pragma   config LVP = OFF         // Single-Supply ICSP disabled
#pragma   config XINST = OFF         // Extended

delay_ms(unsigned int x);                 // function prototype for delay

   
void main()
{
    char TEST = 3;                  // Constant TEST = 3
    enum outputs {LED = 3};   // Constant RELAY = 3
   
    ADCON1= 0b00001111;  // Make all AN0 - AN12 digital inputs
    PORTA = 0;                      // Reset port A
    TRISA = 0xFF;                  // All portA pins are configured as inputs
    PORTD = 0;                        // Reset port D
    TRISD = 0b11110111;       // Pin RD3 is configured as an output, while the rest are
                                          // configured as inputs
   

   
    T0CON=0b11111000;        // ON Timer 0,
    TMR0 = 0;                               // Reset timer/counter TMR0
   
    do {
        if (TMR0 == TEST)              // Does the number in timer match constant TEST?
        {PORTD.LED = 1;                // Numbers match. Set the RD3 bit (output LED
         delay_ms(1500);
        }
    }
    while (1);                              // Remain in endless loop
}


delay_ms(unsigned int x)      // delay 1 mS   
{
   for(;x>0;x--);
   {
   T0CON=0b10010000;    //Fosc 4MHz, Timer 0,16-bit mode, prescaler 1:2, use internal clock, increment on positive-edge
   TMR0H=0xF6;
   TMR0L=0X3C;
   T0CONbits.TMR0ON=1;
   while(INTCONbits.TMR0IF==0);
   T0CONbits.TMR0ON=0;
   INTCONbits.TMR0IF=0;
   }      
}


[mohdismiaswaly]

Any thoughts?
Mr.Ober?

[Idris]

Hi mohdismiaswaly,

Looking at your schematic, you need to set external clock for Timer 0 because you use switch to trigger. But from your code, I see the comment here "use internal clock".

CODE: SELECT_ALL_CODE

T0CON=0b10010000;    //Fosc 4MHz, Timer 0,16-bit mode, prescaler 1:2, use internal clock, increment on positive-edge

So maybe you need to change that to external clock. Correct me if I'm wrong.

[mohdismiaswaly]

Hi mohdismiaswaly,

Looking at your schematic, you need to set external clock for Timer 0 because you use switch to trigger. But from your code, I see the comment here "use internal clock".

CODE: SELECT_ALL_CODE

T0CON=0b10010000;    //Fosc 4MHz, Timer 0,16-bit mode, prescaler 1:2, use internal clock, increment on positive-edge

So maybe you need to change that to external clock. Correct me if I'm wrong.

Hello Idris,

You mean the configuration bit in T0CON<5>, yes, I think that's maybe too. Because I connect the switch to pin T0CK1, so I need to set bit 5 in T0CON register, right?

[mohdismiaswaly]

Hello Idris,

I forgot, the T0CON configuration that you mentioned just as above is for creating a timer for my delay function in the do-while statement. Therefore bit 5 in T0CON register is cleared to enable a timer function, not a counter.

But,the other T0CON configuration in the upper code area I set 1 for bit 5 to enable counter.