Atmega168PA Fuse Value Problems..

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Greetings to all the AVR Geeks,

 

I am a newbie for avr chips. 2 days back i bought Atmega168PA chip and wrote uart program for it in atmel studio 7.0. The code was tested in proteus simulator and found it working. I am using 11.0592 external crystal and also defined F_CPU symbol in my code. Problem came when i modified the fuse bits of uC in AVR dude and uploaded to the chip over writting default fuse values. Still i have not uploaded the hex file. I dont know what values i have written in the uC. At this point avr dude is not able to communicate to uC. The device signature always received is 0x000000. I have tried to fix bad fuse settings by reading this article. Still no luck. I have googled and found that HVPP or HVSP can help but i don't know how to connect AVR Dragon to my uC. Any help will be appreciated.

 

I have AVR Dragon, USBASP and a blown uC(Atmega168PA).

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Have a read of this:

 

https://www.avrfreaks.net/forum/t...

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Hey clawson,

 

Thanks for the post. I have gone through it but my mind is totally mixed up. I am not the hardware expert so i would like to go step by step. Can you please help me how to connect Atmega168Pa to HVPP to avr dragon ? I think i need to connect avr pins mentioned in image 1.png to pins of Atmega168PA shown in 2.png. After the connection is done which software tool should i use to repair the fuses.

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Is this a socketed mega168 or is it already in circuit?

 

Anyway the connections are shown in the manual here:

 

http://www.atmel.com/webdoc/avrd...

 

EDIT: sorry just realised that is the same as the picture you attached - so I'm not entirely sure what you are asking - aren't these diagrams clear? (it's difficult to see how thy could be any clearer!)

Last Edited: Tue. May 3, 2016 - 10:56 AM
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I would not recommend attempting HVPP if you are unsure how the HW works, instead use another MPU as a clock source (toggle an output pin) and use it to inject a clock signal into the xtal1 pin on your MPU as suggested in the link provided to you above.   Then use your ISP to reset your mpu back to factory defaults.  

Then use this site to find the correct fuse settings for proper operation:  http://www.engbedded.com/fusecalc/

 

Jim

 

 

 

 

 

 

 

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Hi, 

Its socked as shown in the attached image. Which software should i used to reset the fuse settings ? Currently i have Atmel studio 7.0.

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