atmega8 got hot!!!

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i got 2 atmega8 chips, one is atmega8L-8PI and the other one is atmega8L-8PU. when i connected them with similar circuits the 8PI got hot and also the l7805 got hot, but the 8PU was fine.

I had another problem which is when i programmed the MCU to blink LED on PC5 the led didn't run but when i programmed it to blink on PB0 it worked fine.

can i know the reason for both issues?

thanks in advance.

Ayman


#ifndef F_CPU
#define F_CPU 1000000UL
#endif
#include <avr/io.h>
#include <util/delay.h>


int main(void)
{
	DDRC|=(1<<PC5);
	
    /* Replace with your application code */
    while (1) 
    {
		PORTC^=(1<<PC5);
		_delay_ms(500);
		
    }
	return(0);
}

 

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Last Edited: Tue. Apr 3, 2018 - 01:51 PM
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Only you can answer the overheating problem

The datasheet answers the second question since you do not post you program. Maybe portc does something else?

No.

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB user

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To answer the first question, we would need to see the schematic or at least a clear picture of your setup.

As for the second question, you would need to show us your code, please use the "<>" code button in the comment menu when posting a reply.

 

Jim

 

Click Link: Get Free Stock: Retire early! PM for strategy

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thanks for your interests. I attached the schematic and the code for the case of PC5 didn't show anything

Last Edited: Tue. Apr 3, 2018 - 01:52 PM
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There are two pair of power pins, VCC/GND and AVCC/GND, BOTH pair need to be connected to the power source, and...

both pair need 100nf caps placed close to the pins.

Yes, even when battery powered!!!

 

Jim

 

Click Link: Get Free Stock: Retire early! PM for strategy

share.robinhood.com/jamesc3274

 

 

 

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I see two potential issues.

1. VCC is not connected to pin20 and GND is not connected to pin22. They should be connected, as well as pins 7 and 8.

2. There is no resistor connected in series with the LED.

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The 7805 requires a 0.33uF capacitor across the input and ground, as close to the physical package as possible.  The output requires a 0.1uF cap across the output and ground, also as close as possible.  Without the output cap, the regulator can go into oscillation, which might cause your symptoms.

 

PORTC output drivers are powered by AVCC, which you have not connected.

"Experience is what enables you to recognise a mistake the second time you make it."

"Good judgement comes from experience.  Experience comes from bad judgement."

"Wisdom is always wont to arrive late, and to be a little approximate on first possession."

"When you hear hoofbeats, think horses, not unicorns."

"Fast.  Cheap.  Good.  Pick two."

"We see a lot of arses on handlebars around here." - [J Ekdahl]

 

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Also, be sure the chip package is not rotated (thus connecting the wrong pins)...It can happen whether using dip or SMD parts.  Orient using the package physical shapes, not the printing.

Your regulator getting hot makes me suspicious of this (the micro with only 1 LED really has no other means to make the lm7805 hot)

 

A chip that got roasted is likely junked, but you can try it again for luck.

 

Draw all of your pins, or maybe cut/paste the datasheet pinout & draw on that.

When in the dark remember-the future looks brighter than ever.

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Get in the habit of drawing a complete schematic before building, even for simple circuits.  It will help you to check each connection has been made correctly, mark off each connection using a highlighter.

 

Good luck with your projects.

 

Jim

 

Click Link: Get Free Stock: Retire early! PM for strategy

share.robinhood.com/jamesc3274

 

 

 

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Get in the habit of drawing a complete schematic before building, even for simple circuits

 

Absolutely agree.

 

There are several free schematic drawing programs available.

 

Here is one that is both free and easy to use:

ExpressPCB's ExpressSCh Classic

(Look under the Free Software Tab)

 

You can download the Schematic drawing program (for free) and use it to draw full schematics for your projects.

You do not have to use the ExpressPCB PCB design software, or their PCB manufacturing.

 

If you use a stand-alone schematic drawing program that is not integrated with a PCB drawing program, then you miss out on the software checking for errors in the layout, but you are still far ahead of the game regarding your prototyping and breadboarding.

 

JC

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If your AVR gets really hot it has probably ceaced to function indefinately just like the Norwegian Blue and can only let more of the magic smoke escape.

As said before quite a lot of extra capacitors are needed. Bulk capacitance before and after the voltage regulator, decoupling caps on both Vcc and aVcc (to GND).

 

Did you upload a new schematic after Marek #6 noticed an absense of a series resistor for the Led?

Schematic is very likely not complete. How do you program the damn thing?

How can we give good advice from too limited info?

What is the total power consumption? If it is above 50mA or so your AVR has probably gone to meet it's maker.

 

 

 

Doing magic with a USD 7 Logic Analyser: https://www.avrfreaks.net/comment/2421756#comment-2421756

Bunch of old projects with AVR's: http://www.hoevendesign.com

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DipTrace also offers a free version of their schematic and pub software as well. So does Eagle

Jim

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB user

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For low budget schematic / PCB design KiCad is rapidly blowing away all competition.

I would not be surprised if KiCad outperforms  > USD 1000 software.

KiCad is pretty intuitive too (for the most part). If you follow the "getting started guide" http://kicad-pcb.org/help/getting-started/  you can draw your first schematic in 1/2 hour. Make your first PCB in a single afternoon.

As an Free & Open Source package there also are no artificial limits buit into KiCad. No limit on pin count. No limit on board size. No limit on number of layer (Well, I believe it does a maximum 32 copper layers).

 

There is also no vendor lock in. You are free to generate PDF, SVG, HPGL, Gerber or other output formats in high resolution.

ngSpice (unfortunately) will not make it in the soon to release Official KiCad V5, but it has been in the nightly (developer & debugging) releases for over a year now.

Doing magic with a USD 7 Logic Analyser: https://www.avrfreaks.net/comment/2421756#comment-2421756

Bunch of old projects with AVR's: http://www.hoevendesign.com