Have I Bricked it?

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What a wazzock...

 

Connected up to a brand new ATMEGA644P with a 20 MHz crystal in place and programmed the CKSEL fuses for low power xtal oscillator and 64ms start up.

 

Of course for a crystal beyond 16MHz I should have used full-swing oscillator...

 

Now it won't talk to me. I've tried fitting two 4 MHz crystals in the hope the fuses programmed OK, but the darn thing refuses to talk (to my AVRISPII)

 

 

Is it likely that I've bricked the thing? I woudl have expected it to fail to verify, but then to be happy with a low frequency xtal. Or could it be an issue with the xtal oscillator?

 

Any kindly suggestions ... I have got an ancient STK500 that may still work so parallel programming may be a possibility, but I've never had to resort to it before.
 

It's me again...

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644 Has JTAG so you might be able to resurrect it with a wee bit of foutering(*1) about.

 

 

*1 Foutering see here. (Definition 2 is perfect in these circumstances.)

SpiderKenny
@spiderelectron
www.spider-e.com

 

Last Edited: Thu. Feb 18, 2016 - 08:32 PM
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I have got an ancient STK500

If the chip is PDIP then the STK500 has a built in clock to get the chip running if you managed to mess up the fuses. Otherwise you may just need to inject a clock int XTAL1.

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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> Otherwise you may just need to inject a clock int XTAL1.

 

Sounds like a plan. Tomorrow I'll hook it up to a scope just in case there is a cloxk and it's something else going pear shaped.

It's me again...

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*1 Foutering see here. (Definition 2 is perfect in these circumstances.)

 

Ah, now I spend a lot of time doing taht without realising I was foutering.

 

Neil

It's me again...

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If you are still unable to get it going you also have HVPP on the STK500 that should allow you to read the fuses to see what went wrong, then reset things

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

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

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Stub_Mandrel wrote:

*1 Foutering see here. (Definition 2 is perfect in these circumstances.)

 

Ah, now I spend a lot of time doing taht without realising I was foutering.

 

Neil

 

Funnily enough it's a word I use a lot, especially towards my 10 year old "Stop foutering about!"

It's pronounced "footering"

SpiderKenny
@spiderelectron
www.spider-e.com

 

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...  xtal oscillator ...

Pay close attention to whether or not you are setting the Fuses to expect the clock source to be an external crystal running with the internal crystal oscillator hardware, or an external crystal oscillator, which is a 4 pin device with its own power, ground, and digital square wave output signal, which feeds O\the micro's Osc 1 pin.

 

It is very easy to make a mistake!

 

JS mentioned injecting a clock signal, (with a common Ground connection), above.

 

Cliff goes into more detains in his De-Bricking tutorial.

 

JC

 

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Hello,

  If the new fuse setting is for a crystal oscillator, then you can't simply attach a crystal.  There has to be an external clock coming into the AVR from an external source.  Which is usually a 4-pin oscillator IC.    You could use the clock output from another AVR IC as an input clock signal.  Check the data sheet for which pin the clock signal is fed into.

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I definitely set the fuses for EXTLOFXTAL_32KCK_65MS

 

Pushing 8mHz into XTL1 hasn't worked so far. Perhaps I need a stronger square wave.

 

Hmm... found my AVR based 0-900 KHz DDS sig gen ... still no success.

It's me again...

Last Edited: Sun. Feb 21, 2016 - 12:43 PM
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DOH!

 

I'll see if I can find a 32KHz watch crystal...

It's me again...

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Can't the DDS do 32k then?

PS since I've been married my Irish wife has often slipped words of Gaelic origin into the conversation. She has a word "foostering" (not entirely sure how that is spelt) that sounds a lot like foutering.

Last Edited: Sun. Feb 21, 2016 - 03:58 PM
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Good point...

It's me again...