Hello
I write only the fuse to my Atmega8 as shown the attached picture. now I can not writing the hex file. and I get message unknown device. I try to erase the device but I can not.
is there a way to erase it.

thanks

 

Can you read the signature?

 

Can you read the signature?

thank you for your reply.
I tried to read the signature. but I can not.
I use the khazam software.

 

You should be able to read the signature regardless of whether the chip is locked or not.

I assume that you are attempting in-system programming (ISP)

Did you ever use this setup before?

Some things you can try:

• Recheck your connections including power supply

• Connect a crystal to XTAL1 and XTAL2 with appropriate load capacitors

• Try high voltage programming

 

You should be able to read the signature regardless of whether the chip is locked or not.

I assume that you are attempting in-system programming (ISP)

Did you ever use this setup before?

Some things you can try:

• Recheck your connections including power supply

• Connect a crystal to XTAL1 and XTAL2 with appropriate load capacitors

• Try high voltage programming

I programed Atmega8 using the --eXtreme Burner - AVR -- software.
but I write all fuse and flash at the same time.
But when I write firstly the fuse, I get this problem -unknown device-
So, I need repaire 4 microcontrller Atmega8 have the same problem.
please, show me the diagram of connecting a crystal to XTAL1 and XTAL2 with appropriate load capacitors .

 

I am sorry that I am not familiar with your programming software. What kind of programmer are you using?

 

the programmer is : 51 avr isp.
the software :I use two
1- Khazama AVR Programmer.
2-eXtreme Burner - AVR.

 

Is it repairable or not?

 

I believe that the settings you show for CKSEL3-0 have selected the internal 8 MHz clock; if that is true, adding an external crystal will not help.

 

He tells how to fix this here http://mightyohm.com/blog/2008/09/arduino-based-avr-high-voltage-programmer/
Add here he goes into better details
https://www.gammon.com.au/forum/?id=12898

 

As an alternative, you might want to consider a Fuse Restorer.

http://www.ebay.com/itm/ATMEL-AVR-A...67a1b60&pid=100005&rk=2&rkt=6&sd=152200630512

http://www.microcontrollerprog.com/fuseprog.html

http://www.ebay.com/itm/ATMEL-AVR-ATMEGA-ATTINY-Fuse-Repair-Programmer-Fuse-Doctor-/222337308536
http://www.ebay.com/itm/ATMEL-AVR-ATMEGA-ATTINY-Fuse-Repair-Programmer-Fuse-Doctor-/222337308536
https://www.aliexpress.com/item/Free-shipping-USB-interface-of-AVR-high-voltage-fuse-restorer-programmer-AVR-M8-M16-parallel-programmer/32796847131.html?spm=2114.search0305.4.6.0mf2nI

http://www.ebay.com/itm/222408846879?rmvSB=true
http://www.ebay.com/itm/222408846879?rmvSB=true
You can find more by Googling "Fuse Restorer" or AVR Fuse Restorer" without the quotes.