Someone tell me what's wrong with a simple led blinking program/circuit!

[DanT29]

Hey guys can someone tell me what I'm doing wrong with the simple led blinking program. I'm using the PIC16f628a, Hi-Tech C complier(Lite), pickit 2 and MPLAB v8.88.

#include<htc.h>
#define _XTAL_FREQ 4000000

void main (void){

TRISB=0b00000000;
PORTB=0b00000001;

while(1){
PORTB=0b00000000;
__delay_ms(1000);
PORTB=0b000000001;
__delay_ms(1000);
}
}

I have also used this code and it does not work:

#include<htc.h>
#define _XTAL_FREQ 4000000

void main (void){

TRISB=0x00;
PORTB=0xFF;

while(1){
PORTB=0x00;
__delay_ms(1000);
PORTB=0xFF;
__delay_ms(1000);
}
}

I have 5 volts going into VDD and VSS connected to ground while RB0(pin 6) is connected to a resistor which is connected in series with an LED that goes back to ground.

What's odd is when I remove VSS from ground it light's up slightly but doesn't blink. Thanks for the help guys!

 

[markdem]

Could it be that you have the LED the wrong way around? Try to take the LED off and check B0 with a multimeter. That will confirm that the PIC is OK, and the LED is the wrong way around.

Have Fun

 

[Tiwana6330]

Can you share your circuit? Try resistor value of 330 ohm

 

[js]

You can test this:
https://www.oz1bxm.dk/PIC/628LED.htm
Sch, source and hex included!

 

[DanT29]

Thanks for the replies guys. I have to go buy a multimeter soon I keep forgetting to I will check as soon as I get one. As for posting my circuit do you guys know any good software I can use to simulate and post the design of my circuit? Thanks for the link also!

- - - Updated - - -

Using the link https://www.oz1bxm.dk/PIC/628LED.htm given to me, I was able to make the led blink. So there is a software issue I believe can anyone help with that? I don't really understand assembly and I want to code in C. I also do not know why there is a 5v supply connected to the MCLR in the link I posted any clarifications will be greatly appreciated!

 

[js]

watchdog is OFF?
if not at begining of your code disable it!

__config _INTRC_OSC_NOCLKOUT & _LVP_OFF & _WDT_OFF & _PWRTE_ON & _BODEN_ON

 

[rajudp]

check for mlcr pin

 

[DanT29]

Can someone tell me what's wrong with this code? My diagram is similar to the one posted on this website : https://www.oz1bxm.dk/PIC/628LED.htm except I am using Pin RB8 to go into the LED and my MCLR goes directly to 5V without a resistor.

#include<htc.h>
#include<stdio.h>
#include <stdlib.h>

#define _XTAL_FREQ 4000000



int main(void)
{
__CONFIG(FOSC_INTOSCIO& LVP_OFF & WDTE_OFF   & PWRTE_ON  & BOREN_ON);
	TRISB=0x00; // PORTB is output

while(1)
{
	PORTB=0x00;
	__delay_us(1000);
	PORTB=0xFF;
	__delay_us(1000);
}

return (0);

}

 

[hemnath]

As for posting my circuit do you guys know any good software I can use to simulate and post the design of my circuit?

Use proteus for simulation.
Also check the crystal connections to uC.

Best wishes