[AVR] Microocntroller not working as before after exposure to Heat gun

[kunal5959]

I used a heat gun for a PCB with ATMega128 and simple circuit consisiting of serial interface, Power supply and ADC. After the exposure a simple toggling function shows this strange behaviour so when port pin is set to low it shows a very slow decay to reach from high to low. Normally it should be immediate transition to high or low without delay. and if the delay between port set and port clear is less than 1 millisecond the signal does not toggle. I am sure its a hardware problem.. Guess that the hardware is effected by the over exposure to hea gun because the PCB was very hot after the exposure. How can i diagnose which part has to be changed or replaced?.


The code for toggling the PORTC pin is

#include <avr/io.h>
#include <util/delay.h>
# define F_CPU 1830000UL

//# define speedPIN PORTC2
//# define dir1PIN  PORTC1
//# define dir2PIN  PORTC0


int main(void)
{
	DDRC=0x00 ;
	//int speed= 0;
	//int dir=1;
	
	
    while(1){
		
		
		PORTC|=(1<<PORTC0);
		_delay_ms(1);
		PORTC&=~(1<<PORTC0);
		_delay_ms(1);
		
	}
 
}

The oscilloscope reading for toggle function is in attachment :-

Please guide me for the diagnose process. Could it be some hardware problem such as loosened connection of Microcontroller pins to PCB board or some capacitor burnout.!

 

[udayan92]

I think the PORTC pins of the Microcontroller you soldered on to the PCB using the heat gun,were the ones that got affected by the excess heat.Test the Microcontroller through a 40 pin IC tester.From what you have described,it looks like the internal chip inside the Microcontroller also might have gotten affected.