# AVR fuse bits problem

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#### vinodstanur

Hi,
This was my only problem which I am always facing after moving from pic to avr. I am using usbasp programmer. Lot of avr chips are screwed due to fusebit problem. But the interesting thing is, it is getting screwed some time even if we are not doing any thing on the fuse. Just burning flash also makes the fuse bits screwed some time... Today I ordered few pcb with smd AVR chips and provided ISP programming feature. Playing for around 30 minutes on one board made it screwed... :-(
No way to take that smd atmega328 to a parallel programmer to correct its fuse... So it seems that the board is waste...

Even I am using -u option in the command line to prevent reading and burning fuse while normal flash programming.,...

Pls help me,...

#### alexxx

I am using usbasp programmer. Lot of avr chips are screwed due to fusebit problem. But the interesting thing is, it is getting screwed some time even if we are not doing any thing on the fuse. Just burning flash also makes the fuse bits screwed some time...
Hi!
Such a behaviour seems very strange. I have seen open source usbasp applications in the web but never used them. I have used several ISP programmers without the slightest problem. Are you sure there is nothing wrong with the programmer's firmware? I don't think it is an AVR problem.

#### tpetar

It is user error made ​​the wrong choice of fuses.

;-)

#### vinodstanur

I am using the usbasp firmware binary and didn't modified it....
Most time it works but some time it gets screwed....
After that I couldn't do further programming... Most time I used to provide external clock frequency and make it work... But this time that also not working....
It is a bad design by Atmel..;-) There should be some easy fuse resetting options in the hardware....

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Hi!
Such a behaviour seems very strange. I have seen open source usbasp applications in the web but never used them. I have used several ISP programmers without the slightest problem. Are you sure there is nothing wrong with the programmer's firmware? I don't think it is an AVR problem.
Hi alexxx,
Hi!
Such a behaviour seems very strange. I have seen open source usbasp applications in the web but never used them. I have used several ISP programmers without the slightest problem. Are you sure there is nothing wrong with the programmer's firmware? I don't think it is an AVR problem.
Hi Alexxx, now I also have the same doubt. I am sure it is not avr's problem but I dislike the avr's design. Some thing should be there to repair it easily via the ISP itself because it is very very hard to take the smd avr from pcb to a prarllel HVP to reset the fuse. Practically better is the replace the chip...

I will try for the latest usbasp firmware, I am using 1 year ago's firmware right now... (made it 1 year ago)..

Also I am having avr dragon programmer but didn't tried it since I am always using GNU/LINUX for the development....

#### tpetar

Some thing should be there to repair it easily via the ISP itself because it is very very hard to take the smd avr from pcb to a prarllel HVP to reset the fuse. Practically better is the replace the chip...

Use hot air to desolder TQFP cases and other SMD chips, its job for kids, and use flux.

Programmer USBasp works like charm. You will not solve fuse problem with some programmer settings or changing programmer firmware.

Hot air station nozzles photos :

Programming adapter, you dont need to solder to program chip :

:wink:

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#### alexxx

Some thing should be there to repair it easily via the ISP itself because it is very very hard to take the smd avr from pcb to a prarllel HVP to reset the fuse. Practically better is the replace the chip...
This thing is not meant to happen, unless fusebits are not configured correctly.
But you are right, the design could be easier for developers when by accident they configure fusebits incorrectly. I agree, better replace the chip. ATmega 328 should be easy to desolder even with a soldering iron.
If however you are absolutely positive that you download the same project to all MCUs without changing anything, then it would be reasonable to update its firmware and see how it goes.

#### Magvitron

##### Full Member level 5
try to program using a hv programmer described in arduino main site. try soldering wires from the MISO, MOSI, reset pins and then solder it to the programmer. might work. give it a try. avr fuse bits problems are common. its not the problem of avr architecture , but of the user

#### tpetar

Atmega fusebit doctor (HVPP+HVSP) – fix the fusebits
http://mdiy.pl/atmega-fusebit-doctor-hvpp/?lang=en

HVPP = high voltage parallel programming
HVSP = high voltage serial programming

Use SMD to DIP adapters for SMD devices.

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#### alexan_e

ass? :lol:

P.S. an ass addon... interesting concept :lol:

#### tpetar

ass? :lol:

P.S. an ass addon... interesting concept :lol:
Oh yes sorry what one additional s can do.

#### vinodstanur

Use hot air to desolder TQFP cases and other SMD chips, its job for kids, and use flux.
.
Programmer USBasp works like charm. You will not solve fuse problem with some programmer settings or changing programmer firmware.
:wink:

Any way for me it is not so easy..... Also my package is very small (32-QFN). I know it is not due to AVR architecture problem.
I just commented it is a bad design by the Atmel. Otherwise they can easily implement a fuse bit reset to default option by some simple way in the hardware itself so that no need to take the chip using hot air pump etc...

It happens only due to improper fuse bits. But for me it happens frequently even if I am not burning the fuse directly but I dont know why. It can happen at any time while programming the flash memory in my case. I am always worried of this problem nowadays especially while dealing with smd avrs...
I have many chips with me which got screwed while programming the flash only. I repaired most of them using avr dragon programmer. Then I started using -u option in the command line for avrdude to prevent this error... Still I got one new board screwed...

Does any one used AVR dragon ISP with avrdude ? Can I use it in linux?

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Also now I prefer a bootloader always because it is reliable and no worry about fuse bit problem unless I am trying to modify it....

#### ctownsend

Any way for me it is not so easy..... Also my package is very small (32-QFN). I know it is not due to AVR architecture problem.
I just commented it is a bad design by the Atmel. Otherwise they can easily implement a fuse bit reset to default option by some simple way in the hardware itself so that no need to take the chip using hot air pump etc...

It happens only due to improper fuse bits. But for me it happens frequently even if I am not burning the fuse directly but I dont know why. It can happen at any time while programming the flash memory in my case. I am always worried of this problem nowadays especially while dealing with smd avrs...
I have many chips with me which got screwed while programming the flash only. I repaired most of them using avr dragon programmer. Then I started using -u option in the command line for avrdude to prevent this error... Still I got one new board screwed...

Does any one used AVR dragon ISP with avrdude ? Can I use it in linux?

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Also now I prefer a bootloader always because it is reliable and no worry about fuse bit problem unless I am trying to modify it....
you probably programmed the CKSEL fuses incorrectly.
Look at my post here:

99% this should fix your problem

#### tpetar

Any way for me it is not so easy..... Also my package is very small (32-QFN). I know it is not due to AVR architecture problem.
I just commented it is a bad design by the Atmel. Otherwise they can easily implement a fuse bit reset to default option by some simple way in the hardware itself so that no need to take the chip using hot air pump etc...

It happens only due to improper fuse bits. But for me it happens frequently even if I am not burning the fuse directly but I dont know why. It can happen at any time while programming the flash memory in my case. I am always worried of this problem nowadays especially while dealing with smd avrs...
I have many chips with me which got screwed while programming the flash only. I repaired most of them using avr dragon programmer. Then I started using -u option in the command line for avrdude to prevent this error... Still I got one new board screwed...

Does any one used AVR dragon ISP with avrdude ? Can I use it in linux?

- - - Updated - - -

Also now I prefer a bootloader always because it is reliable and no worry about fuse bit problem unless I am trying to modify it....
TQFP32 is not hard to desolder and solder, main thing is to use flux. You can watch some videos on Youtube.

Soldering a TQFP32 by hand

QFP32 Removal (Real Man´s Method)

#### nandhu015

You need a HVPP only if you disable SPIEN bit. Else every problem can be solved without HVPP.

All you need is few oscillator circuits to correct all the problems.

#### vinodstanur

Hi now solved the issue... I was programming the 3.3v line connected AVR with 5V level USBASP programmer. This is making problem.
So I powered the mcu with 5v and there after the fusebit problem doesn't happened...
Before that when ever I try to program correct fuse, most time it is written wrong fuse and this screwed the avr...