AVR-Chat

Hi everyone,

I seem to have a bad batch of mega 128's in that for the current project I
am finding that 20 to 30% of the chips are not programmable, or some appear
to have faulty A/D ports.

Out of 32 units last weekend, I had to replace 12 parts, and the lot before
that I had to replace 9 of 31.

Has anyone come across this sort of thing before? I've checked with the
boardhouse that is assembling the PCB's and they have their ovens set up
correctly so I'm thinking that it must truly be a bd batch of parts.

Dean


[Non-text portions of this message have been removed]

There has been a spate of "forged" AVRs from China. I would not be  
surprised if there are also some that failed test but got stolen and  
sold. That was a BIG problem in the US a few years back, so I'd not be  
surprised if that tactic shows up again.

Jim Wagner
Oregon Research Electronics

On May 30, 2010, at 6:32 PM, Dean Claxton wrote:

> Hi everyone,
>
> I seem to have a bad batch of mega 128's in that for the current  
> project I
> am finding that 20 to 30% of the chips are not programmable, or some  
> appear
> to have faulty A/D ports.
>
> Out of 32 units last weekend, I had to replace 12 parts, and the lot  
> before
> that I had to replace 9 of 31.
>
> Has anyone come across this sort of thing before? I've checked with  
> the
> boardhouse that is assembling the PCB's and they have their ovens  
> set up
> correctly so I'm thinking that it must truly be a bd batch of parts.
>
> Dean
>
> [Non-text portions of this message have been removed]
>
>
> 



[Non-text portions of this message have been removed]

On Sun, May 30, 2010 at 7:32 PM, Dean Claxton <deanclaxton@gmail.com> wrote:
> Hi everyone,
>
> I seem to have a bad batch of mega 128's in that for the current project I
> am finding that 20 to 30% of the chips are not programmable, or some appear
> to have faulty A/D ports.

Are you running crystal oscillator with the CKOPT fuse in the default state?

On Sun, May 30, 2010 at 9:32 PM, Dean Claxton <deanclaxton@gmail.com> wrote:

>
>
> Has anyone come across this sort of thing before? I've checked with the
> boardhouse that is assembling the PCB's and they have their ovens set up
> correctly so I'm thinking that it must truly be a bd batch of parts.
>

Check your static controls.  Humidity has changed for the summer season,
there is also counterfeit ESD stuff showing up now.  Like we didn't have
enough problems with counterfeit parts.

Do the A/D pins that are failing have a more direct path to the outside
world than other pins?  That would fit the ESD hypothesis.

http://blog.softwaresafety.net/2010/05/counterfeit-esd-products-guide-on-emc.html

http://blog.softwaresafety.net/2010/04/software-bug-or-electrostatic-discharge.html


-- 
http://blog.softwaresafety.net/
http://www.designer-iii.com/
http://www.wearablesmartsensors.com/


[Non-text portions of this message have been removed]

Hi David,

External oscialltor, and I normally enable CKOPT during programming but the
ones that fail do not get that far - fail to read fuses or program. If I
replace the MCU then all good, so I assume the actual MCU is the issue.

On Mon, May 31, 2010 at 12:59 PM, David VanHorn <microbrix@gmail.com> wrote:

> On Sun, May 30, 2010 at 7:32 PM, Dean Claxton <deanclaxton@gmail.com>
> wrote:
> > Hi everyone,
> >
> > I seem to have a bad batch of mega 128's in that for the current project
> I
> > am finding that 20 to 30% of the chips are not programmable, or some
> appear
> > to have faulty A/D ports.
>
> Are you running crystal oscillator with the CKOPT fuse in the default
> state?
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>
>


-- 
Kind Regards
Dean Claxton


[Non-text portions of this message have been removed]

Sorry - I should have said crystal oscillator, and I check the CKOPT box.
The programmer (STK500) fails to read fuses etc though for these MCU's and
will not program them.

On Tue, Jun 1, 2010 at 8:46 AM, Dean Claxton <deanclaxton@gmail.com> wrote:

> Hi David,
>
> External oscialltor, and I normally enable CKOPT during programming but the
> ones that fail do not get that far - fail to read fuses or program. If I
> replace the MCU then all good, so I assume the actual MCU is the issue.
>
>   On Mon, May 31, 2010 at 12:59 PM, David VanHorn <microbrix@gmail.com>wrote:
>
>> On Sun, May 30, 2010 at 7:32 PM, Dean Claxton <deanclaxton@gmail.com>
>> wrote:
>> > Hi everyone,
>> >
>> > I seem to have a bad batch of mega 128's in that for the current project
>> I
>> > am finding that 20 to 30% of the chips are not programmable, or some
>> appear
>> > to have faulty A/D ports.
>>
>> Are you running crystal oscillator with the CKOPT fuse in the default
>> state?
>>
>>
>> ------------------------------------
>>
>> Yahoo! Groups Links
>>
>>
>>
>>
>
>
> --
> Kind Regards
> Dean Claxton
>



-- 
Kind Regards
Dean Claxton


[Non-text portions of this message have been removed]

Thanks Bob,

I'll check with the board assembly shop to ensure they have ESD precautions
in place.

Dean

On Mon, May 31, 2010 at 7:41 PM, Bob Paddock <bob.paddock@gmail.com> wrote:

> On Sun, May 30, 2010 at 9:32 PM, Dean Claxton <deanclaxton@gmail.com>
> wrote:
>
> >
> >
> > Has anyone come across this sort of thing before? I've checked with the
> > boardhouse that is assembling the PCB's and they have their ovens set up
> > correctly so I'm thinking that it must truly be a bd batch of parts.
> >
>
> Check your static controls.  Humidity has changed for the summer season,
> there is also counterfeit ESD stuff showing up now.  Like we didn't have
> enough problems with counterfeit parts.
>
> Do the A/D pins that are failing have a more direct path to the outside
> world than other pins?  That would fit the ESD hypothesis.
>
>
> http://blog.softwaresafety.net/2010/05/counterfeit-esd-products-guide-on-emc.html
>
>
> http://blog.softwaresafety.net/2010/04/software-bug-or-electrostatic-discharge.html
>
>
> --
> http://blog.softwaresafety.net/
> http://www.designer-iii.com/
> http://www.wearablesmartsensors.com/
>
>
> [Non-text portions of this message have been removed]
>
>
>
>  ------------------------------------
>
> Yahoo! Groups Links
>
>
>
>


-- 
Kind Regards
Dean Claxton


[Non-text portions of this message have been removed]

You are not alone...

http://www.sparkfun.com/commerce/news.php?id=364

It seems we go through "boom/bust" times with Atmel parts.  I love their 
processors but hate their fab - supply shortages happen every so often 
with them.

DLC

Dean Claxton wrote:
> Sorry - I should have said crystal oscillator, and I check the CKOPT box.
> The programmer (STK500) fails to read fuses etc though for these MCU's and
> will not program them.
> 
> On Tue, Jun 1, 2010 at 8:46 AM, Dean Claxton <deanclaxton@gmail.com> wrote:
> 
>> Hi David,
>>
>> External oscialltor, and I normally enable CKOPT during programming but the
>> ones that fail do not get that far - fail to read fuses or program. If I
>> replace the MCU then all good, so I assume the actual MCU is the issue.
>>
>>   On Mon, May 31, 2010 at 12:59 PM, David VanHorn <microbrix@gmail.com>wrote:
>>
>>> On Sun, May 30, 2010 at 7:32 PM, Dean Claxton <deanclaxton@gmail.com>
>>> wrote:
>>>> Hi everyone,
>>>>
>>>> I seem to have a bad batch of mega 128's in that for the current project
>>> I
>>>> am finding that 20 to 30% of the chips are not programmable, or some
>>> appear
>>>> to have faulty A/D ports.
>>> Are you running crystal oscillator with the CKOPT fuse in the default
>>> state?
>>>
>>>
>>> ------------------------------------
>>>
>>> Yahoo! Groups Links
>>>
>>>
>>>
>>>
>>
>> --
>> Kind Regards
>> Dean Claxton
>>
> 
> 
> 

-- 
-------------------------------------------------
Dennis Clark          TTT Enterprises
www.techtoystoday.com
-------------------------------------------------

On Mon, May 31, 2010 at 4:46 PM, Dean Claxton <deanclaxton@gmail.com> wrote:
> Hi David,
>
> External oscialltor, and I normally enable CKOPT during programming but the
> ones that fail do not get that far - fail to read fuses or program. If I
> replace the MCU then all good, so I assume the actual MCU is the issue.


Just checking, that low power oscillator will give you symptoms like
you'd described.