Problem with cheap chinese ATMEGAs in QFP32 package

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Hello, avrfreaks community!

 

I recently purchased several atmega328p chips from a well-known chinese online store (decided to go as low budget as possible) in QFP32 package for my next project. But I cannot seem to get them to work and cannot figure out what's the problem with them.

 

The atmegas arrived in the most ghetto package I've seen so far:

 

But that's fine with me as long as they work.

 

So I made a breakout board to test them (don't mind the crappy soldering, a continuity test was done so it's all fine).

 

I hooked it up to a USBASP and checked the connection with avrdude. It worked fine, it showed the fuse bits, the signature and all that goodness. Then I flashed it with the arduino bootloader. It showed the flashing process completed without errors, verification was also done without errors. Fuse bits were the same aflter flashing.

 

And then the funny part. After cycling the power (reconnecting the USBASP) the chip basically died --  the arduino bootloader-specific D13 led blinking at the bootup was not there. And it even stopped responding to serial programming!

I blamed my bad luck and figured the chip somehow actually died on me, but since I got em cheap I didn't bother much and just soldered another one in it's place. And from there on I was not able to get any of the chips I bought to work via USBASP. I've tried 5 out of 10 I bought so far.

 

I googled around and found some ideas to check -- like using an external oscillator or checking the "reset disable" bit.

 

Hooking up the chip to a 16mhz crystal (with 22pf caps) didn't work. But as far as I remember ICSP does not require an external oscillator at all since it's clocked with the SCK signal.

 

To check the "reset disable" fuse bit I borrowed a Dragon from an acquaintance of mine and hooked the board to it. This was the first time I was dealing with this beast so I didn't really know how to wire it correctly.

There are tons of info on how to do it with DIP-packaged ATMEGA but for QFP package there are only general suggestions like "get a QFP-to-DIP adapter and you're good", nothing concrete. I don't have one right now so I decided to make do with what I have.

 

 

I used this datasheet (http://www.atmel.com/webdoc/avrdragon/avrdragon.SCKT3200A2.html) to look up how to wire the HV_PROG pins to DIP pins and then used pinouts like these (https://it4it.club/uploads/monthly_2015_10/Atmega328P-AU.png.586d20b9b1c24ae595477930b3463353.png, http://cdn.instructables.com/F5B/UYWP/I63F0MTK/F5BUYWPI63F0MTK.MEDIUM.jpg) to correspondingly wire my QFP chip. So that, for instance, the pin#1 on HV_PROG connector wires to pin#12 on my QFP ATMEGA. But unfortunately that didn't work. Atmel Studio 7 device programming dialog shows it can read 5.0V but the device signature is 0xFFFFFF.

 

And as far as I understand if HVPP does not help then the game is over for good.

 

So here I am now. And before I go on and try to refund my money I'm asking you kind sirs to help me out. Maybe there's something wrong with what I was doing. Or maybe the answer is that it's just a cheap chinese crap.

 

Btw, my electronics skill level is noobish :D

Last Edited: Sun. Dec 29, 2019 - 04:00 AM
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Not working after a reset is often a symptom of bad choice of fuse settings. That is because fuse values are not loaded until a reset happens. One of the biggies is choosing external oscillator instead of crystal or selecting crystal when you mean internal RC oscillator. Another less common one is setting RSTDBL (I think that is its name) which will prevent any future programming. Another is enabling debugwire which will over-ride ISP for programming. Lots of poor choices available!

 

Can you tell us exactly how you set your fuses?

 

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

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Yeah, I know that fuse settings is the most common problem that fits the description. That's why I double-checked the fuses after I flashed the microcontroller the first time. The fuse values were the exactly the same as before flashing -- the microcontroller should have run on internal RC oscillator. Plus I've read that bootloader flashing should not affect fuses at all.

 

Note also that none of the other 4 chips worked via ISP right after I've soldered them onto the board.

 

I'm more interested in why the HVPP didn't work. Isn't it supposed to work regardless of the fuse settings?

Last Edited: Sat. Dec 26, 2015 - 08:12 AM
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You said   "Btw, my electronics skill level is noobish :D "

So why on earth do you tempt fate by fiddling with bare chips on home made adapter, using a Dragon in HVPP, .... etc

The moment you programmed the Arduino bootloader, you bricked you 328's: they have no longer a clock.

 

An Arduino Nano $3  http://www.banggood.com/ATmega32...

or Mini $ 2.63  http://www.banggood.com/Pro-Mini...

Uno $ 4.12  http://www.banggood.com/ATmega32...

.... and you're good to go.

 

You are blaming the Chinese. You shouldn't. Be a man and take the blame yourself.

A GIF is worth a thousend words   They are called Rosa, Sylvia, Tricia, and Ulyana. You can find them https://www.linuxmint.com/

Dragon broken ? http://aplomb.nl/TechStuff/Dragon/Dragon.html for how-to-fix tips

Last Edited: Sat. Dec 26, 2015 - 01:15 PM
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I need a low power consumption and a small footprint in my battery-powered wireless sensor. That's why I moved from arduino to a bare chip.

 

Testing a bare chip on a homemade board is not a rocket science. If you wire it right it should just work. Tempting fate has nothing to do with it.

 

Blaming the Chinese is a totally valid point. Counterfeit electronic components are everything but rare. Especially when bought cheap. Especially from online stores. I will blame myself as soon as I make sure I'm to blame.

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Um. Yea. Your chip now thinks it's in an Arduino, but your board is missing a couple important Arduino components, like a crystal and load caps. Bypass caps too.

If you don't know my whole story, keep your mouth shut.

If you know my whole story, you're an accomplice. Keep your mouth shut. 

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Please, read my post more carefully.

 

The bootloader was flashed only on the first chip out of 5 I've tried. The other 4 did not respond to ISP right from the beginning.

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I hooked it up to a USBASP and checked the connection with avrdude. It worked fine, it showed the fuse bits, the signature and all that goodness.

That would imply that the micro was working properly, and isn't a counterfeit chip.

The counterfeit chips generally aren't functional uC's at all, and don't report a correct Signature when quired.

 

Your micro's certainly need By-Pass caps.

Do you have ALL of the Vcc and the AVcc tied to V+, and ALL of the Grounds tied to Ground?

 

With one of your remaining new chips you should simply load a flash the LED program BEFORE trying to load a Bootloader, or anything else.

 

JC

 

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DocJC wrote:

That would imply that the micro was working properly, and isn't a counterfeit chip.

 

That's not entirely correct. Counterfeit chips are almost always working ones. It's the materials and technology where the corners are being cut, as well as avoiding paying royalties and license fees and skipping quality control. So by buying cheap electronics you're basically playing a roulette. But no matter the odds, sometimes you're just strictly being sold crap that wasn't intended to be working at all (I've read about cases like these somewhere on the net). I was lucky up until this point and everything I bought worked. Now is the case when I'm not sure where the problem is - my hands or the hands that made those micros.

 

DocJC wrote:

Your micro's certainly need By-Pass caps.

Do you have ALL of the Vcc and the AVcc tied to V+, and ALL of the Grounds tied to Ground?

 

Ok, I will try the bypass caps.

But to be honest I still don't see how it will help. Bypass caps are needed to make current more stable by filtering out noise and (with larger capacities) protect against short surges and drops. USBASP gets its power from a USB controller, which in turn is powered by a motherboard, which is powered by a power supply. Each of those components have its own current stabilizing circuits. Besides the MCU on my board is not doing anything, it's just a test board, there is no load. So how could bypass caps help me here?

 

As for hooking up all the Vcc and GND. Yes, I did try that too, but to no effect. And to my knowledge, that's not needed anyway. There are two parts in the atmega uC that are powered separately -- the main circuits and the ADC converter. The latter is not used for serial programming as far as I know. And the other Vcc and GND pins are internally connected anyway. Yes, in production they all should be connected, but for a test breakout board I think it's superfluous.

 

DocJC wrote:

With one of your remaining new chips you should simply load a flash the LED program BEFORE trying to load a Bootloader, or anything else.

 

Sadly, there is no "anything else". I can't access the chips via ISP, hence I can't even flash anything.

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Hmmm, for someone who says...

 

zdazzy wrote:
Btw, my electronics skill level is noobish :D

 

...you are making quite a few claims which appear to be wrong. For example, you say...

 

zdazzy wrote:
but for a test breakout board I think it's superfluous.

 

...and yet the datasheet says...

 

Quote:
AVCC is the supply voltage pin for the A/D Converter, PC3:0, and ADC7:6. It should be externally connected to VCC,
even if the ADC is not used.
(my bold).

 

 

#1 Hardware Problem? https://www.avrfreaks.net/forum/...

#2 Hardware Problem? Read AVR042.

#3 All grounds are not created equal

#4 Have you proved your chip is running at xxMHz?

#5 "If you think you need floating point to solve the problem then you don't understand the problem. If you really do need floating point then you have a problem you do not understand."

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You just need to say : "my skills are limited"
Then it totally absolves you from obeying the Laws of Physics.

Personally, I am a "rule of thumb" person. I will do detailed calculations occasionally.
But most of the time, you just follow the advice from data sheets. e.g. 100nF wherever specified, pins connected as specified.

Yes, you might be able to save $0.002 sometimes if you can use a different component. But you need to justify it with full calculations.

David.

Last Edited: Sat. Dec 26, 2015 - 04:49 PM
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Welcome to AVR Freaks!

 

Now that that's out of the way... what a load of rubbish.

 

You seem be utterly convinced of a great number of things which are demonstrably incorrect.  Let's set the record straight lest a future novice stumble across your thread and be led astray by your misconceptions:

 

  • You >>must<< apply power to all pins.  That means all Vcc/AVcc pins, and all GND pins.  Period.  Even if you are not using the ADC or other analog features, you must apply power to the AVcc pins.  The only option you have is whether to employ an LC filter for AVcc.
  • You >>must<< have bypass caps across >>all<< pairs of power.  That means all Vcc/AVcc pins must be bypassed with a 100 nF cap across to the nearest GND pin, and as close to the package as possible (i.e. with as short as possible connections).

 

But to be honest I still don't see how it will help. Bypass caps are needed to make current more stable by filtering out noise and (with larger capacities) protect against short surges and drops.

You are confusing bypass/decoupling caps with power supply filtering.  They are not the same.  Bypass caps are intended to smooth the extremely sharp and high frequency (often multi-hundred megahertz) noise induced on the power bus by the device itself, as a result of internal logic switching.  It has almost nothing to do with the loads which the device might be switching on its GPIO pins.  Without bypassing, the noise and ringing on the power bus will remain un-damped and unchecked and can adversely affect the operation of not only the device itself, but other devices sharing the power bus, including the programmer you are using.  So yes, bypass is necessary even when only programming.  It >>might<< work without bypass.  It might not.  Running or programming without bypass is driving the device out of spec.  Period.  Do so at your own peril.

 

There are two parts in the atmega uC that are powered separately -- the main circuits and the ADC converter.

More rubbish.  They are not entirely separate.  Leaving AVcc unpowered means that Vcc will pull up AVcc via its internal protection diode.  This will leave AVcc with a voltage drop of at least 0.7V below Vcc.  This is far out of spec.  This means that other internal logic connections between the core and those components powered by AVcc will be operating at different voltages.  AVcc also provides power for some non-analog portions of the core.  On the 328P, that includes PORTD[3:0].

 

That's not entirely correct. Counterfeit chips are almost always working ones. It's the materials and technology where the corners are being cut, as well as avoiding paying royalties and license fees and skipping quality control. So by buying cheap electronics you're basically playing a roulette. But no matter the odds, sometimes you're just strictly being sold crap that wasn't intended to be working at all (I've read about cases like these somewhere on the net). I was lucky up until this point and everything I bought worked. Now is the case when I'm not sure where the problem is - my hands or the hands that made those micros.

Again, rubbish.  Where is the documentation to support your claim that 'Counterfeit chips are almost always working ones'?  There are perhaps three or four kinds of 'counterfit' AVR:

 

  1. non-functioning silicon slugs labelled as AVR
  2. completely different devices labelled as AVR
  3. production rejects diverted from recycling/destruction and sold illegally
  4. reverse-engineered 'clones' like the Logic Green LGT8F88

 

(See here for details on the first two)

 

I'd suggest that there is a >>remote<< possibility that you are the victim of 3), but that you are almost certainly not the victim of any of the others.  The greatest likelihood is that your cheap but perfectly legitimate AVRs have suffered cumulative and catastrophic ESD damage during the time they were in storage at the vendor, or during transit to or from their warehouse, or during handling and shipping to you.  Cardboard and scotch tape don't make good antistatic shipping materials.  Quite the opposite.  I would refuse any shipment which arrived without proper anti-static protection.  Period.

 

Now on to your problem:  Do you have any other AVR lying around?  Have you tried to program one of them to confirm that your AVRasp is still working properly?

 

"Experience is what enables you to recognise a mistake the second time you make it."

"Good judgement comes from experience.  Experience comes from bad judgement."

"Wisdom is always wont to arrive late, and to be a little approximate on first possession."

"When you hear hoofbeats, think horses, not unicorns."

"Fast.  Cheap.  Good.  Pick two."

"We see a lot of arses on handlebars around here." - [J Ekdahl]

 

Last Edited: Sat. Dec 26, 2015 - 06:00 PM
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Okay, I admit I've been overly assertive. And, as it turns out, even downright wrong at certain things. Thank you for explaining. But hey

joeymorin wrote:
"Good judgement comes from experience. Experience comes from bad judgement."

right? :D

 

joeymorin wrote:
Do you have any other AVR lying around? Have you tried to program one of them to confirm that your AVRasp is still working properly?

Yes, I am able to access my Pro Mini with the same programmer.

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Hi

 

Why not purchase ONE new one chip from a reputable source and with that prove that your methods/practices are correct or not before blaming anyone or anything

 

Regards

Steve

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zdazzy wrote:
But hey
joeymorin wrote:
"Good judgement comes from experience. Experience comes from bad judgement."
right? :D
You bet! ;-)

"Experience is what enables you to recognise a mistake the second time you make it."

"Good judgement comes from experience.  Experience comes from bad judgement."

"Wisdom is always wont to arrive late, and to be a little approximate on first possession."

"When you hear hoofbeats, think horses, not unicorns."

"Fast.  Cheap.  Good.  Pick two."

"We see a lot of arses on handlebars around here." - [J Ekdahl]

 

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So I actually went through all 10 of my ATMEGAs. And the very last one actually worked! It got programmed with no problems whatsoever. The bootloader was flashed successfully and I can actually use it to upload code.

No additional components were needed -- no bypass capacitors and no crystal. Not that I'm trying to prove that they're not needed, all I'm saying is that in my particular case it worked without them.

 

I'm glad to know that I'm not crazy and the world is not falling apart. I'm gonna have a talk with the seller now.

 

But what's the lesson to learn here? Was that an ESD that caused it? Or is the overall low price led to such result?

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zdazzy wrote:
But what's the lesson to learn here? 

That there is no such thing as a free lunch!

 

zdazzy wrote:
decided to go as low budget as possible

If you pay junk prices, you will get junk goods and junk service.

 

Just because something is "cheap" does not mean that it is good value.

 

is the overall low price led to such result?

Yes - you get what you pay for!

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So what happens if you take a non-functioning chip and give it...

 

a) a full set of VCC and GND connections

b) some decoupling

c) an external clock source <- not a crystal, an external clock

 

#1 Hardware Problem? https://www.avrfreaks.net/forum/...

#2 Hardware Problem? Read AVR042.

#3 All grounds are not created equal

#4 Have you proved your chip is running at xxMHz?

#5 "If you think you need floating point to solve the problem then you don't understand the problem. If you really do need floating point then you have a problem you do not understand."

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I vote post #4. That let's you work on projects immediately, skipping the junk.

It all starts with a mental vision.

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So I actually went through all 10 of my ATMEGAs. And the very last one actually worked!

No additional components were needed -- no bypass capacitors

 Maybe the other 9 will work with those "needless" capacitors.

Also I would have all GND's connected, AVCC connected to Vcc, a pull-up resistor on RESET.

Only then I would say working or not working.

Last Edited: Sun. Dec 27, 2015 - 01:37 PM
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Brian Fairchild wrote:

So what happens if you take a non-functioning chip and give it...

 

a) a full set of VCC and GND connections

No effect.

 

Brian Fairchild wrote:
a) a full set of VCC and GND connections

b) some decoupling

No effect. To be more specific, I've added 0.1uF caps across both input voltage pin pairs as well as and analog voltage pin pair (gnd/vcc). Also I've added 100uF cap near the power supply rails.

 

Brian Fairchild wrote:
c) an external clock source <- not a crystal, an external clock

I have nothing to use as a clock source, unfortunately. The closest thing I have is a CLKOUT pin on my logic analyzer that outputs 48Mhz, but that would be outside of what atmega supports I believe.

I guess I could use another atmega as a clock source and just drive a single pin high and low in a loop, using a common ground for both. Will this work?

 

KitCarlson wrote:
I vote post #4. That let's you work on projects immediately, skipping the junk.

Those are only good for prototyping. I'm a little past that stage already and need a more complete and compact solution. Besides, would I have learned many interesting stuff should I have not tried to go low-level?..

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Initially, zdazzy wrote:
decided to go as low budget as possible ... 

Finally, zdazzy wrote:
So I actually went through all 10 of my ATMEGAs. And the very last one actually worked! 

So the "low budget" approach is not looking such good value after all ... ?

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zdazzy wrote:
Those are only good for prototyping. I'm a little past that stage already and need a more complete and compact solution. 

You call this "compact"?

 

There are plenty of Arduino-like and similar boards more complete & compact than that; eg,

 

https://www.pjrc.com/teensy/

 

 

https://www.arduino.cc/en/Main/A...

 

 

IMUduino

http://femto.io/

 

 

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  3. Wrong baud rate is usually due to not running at the speed you thought; check by blinking a LED to see if you get the speed you expected
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awneil wrote:

So the "low budget" approach is not looking such good value after all ... ?

Up until now it was. This is the first time I had problems and I got confused.

 

awneil wrote:
You call this "compact"?

Obviously, this is just a breakout board to run tests on. The end product will be properly routed on a dedicated board.

Last Edited: Sun. Dec 27, 2015 - 01:49 PM
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zdazzy wrote:
I guess I could use another atmega as a clock source and just drive a single pin high and low in a loop, using a common ground for both. Will this work?

 

Yes. Virtually anything you have to hand that will generate a square(ish) wave at 5v pk-pk will work.

#1 Hardware Problem? https://www.avrfreaks.net/forum/...

#2 Hardware Problem? Read AVR042.

#3 All grounds are not created equal

#4 Have you proved your chip is running at xxMHz?

#5 "If you think you need floating point to solve the problem then you don't understand the problem. If you really do need floating point then you have a problem you do not understand."

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Brian Fairchild wrote:
5v pk-pk

 

Or 3v3 pk-pk if that's what your uC runs at.

#1 Hardware Problem? https://www.avrfreaks.net/forum/...

#2 Hardware Problem? Read AVR042.

#3 All grounds are not created equal

#4 Have you proved your chip is running at xxMHz?

#5 "If you think you need floating point to solve the problem then you don't understand the problem. If you really do need floating point then you have a problem you do not understand."

Last Edited: Sun. Dec 27, 2015 - 02:07 PM
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Can you show a picture where we (and Atmel) can see what is printed.

 

there are clones of 328 (LGT8F328) that I guess works, but can't be programmed like an Atmel AVR (but they say that they are ARDUINO compatible)

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sparrow2 wrote:

Can you show a picture where we (and Atmel) can see what is printed.

 

there are clones of 328 (LGT8F328) that I guess works, but can't be programmed like an Atmel AVR (but they say that they are ARDUINO compatible)

Here you go.

 

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The printing on the underside includes fab, lot, and date code. Do all 10 match?

"Experience is what enables you to recognise a mistake the second time you make it."

"Good judgement comes from experience.  Experience comes from bad judgement."

"Wisdom is always wont to arrive late, and to be a little approximate on first possession."

"When you hear hoofbeats, think horses, not unicorns."

"Fast.  Cheap.  Good.  Pick two."

"We see a lot of arses on handlebars around here." - [J Ekdahl]

 

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I didn't know Atmel had fabs in Korea.  And indeed, not according to this site:

http://www.10stripe.com/featured... But as they said there:

This map only shows wafer fabs, and not other production facilities such as package and testing facilities.

And according to Atmel, there may indeed be "assembly" plants in Korea:

http://www.wikinvest.com/stock/A...

After probe, we send all of our wafers to one of our independent assembly contractors, located in China, Indonesia, Japan, Malaysia, the Philippines, South Korea, Taiwan or Thailand where they are cut into individual chips and assembled into packages.

There is a guide to reading the underside chip marks.

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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joeymorin wrote:
The printing on the underside includes fab, lot, and date code. Do all 10 match?

 

8 out of 10 have the same code as in the picture. 2 have different ones.

 

From what I can understand the MCUs are not counterfeit after all.

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It's like pulling teeth from a hen.
Two work. Eight don't.
Two have one set of markings on the underside. Eight have another.
Do I actually have to ask the questions?
OK: Do the eight which don't work all have the same underside markings?
What >>are<< those markings? All of them.

"Experience is what enables you to recognise a mistake the second time you make it."

"Good judgement comes from experience.  Experience comes from bad judgement."

"Wisdom is always wont to arrive late, and to be a little approximate on first possession."

"When you hear hoofbeats, think horses, not unicorns."

"Fast.  Cheap.  Good.  Pick two."

"We see a lot of arses on handlebars around here." - [J Ekdahl]

 

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zdazzy wrote:

8 out of 10 have the same code as in the picture. 2 have different ones.

... 2 of yours showed some signs of life, do they align with lots here ?

 

zdazzy wrote:

I guess I could use another atmega as a clock source and just drive a single pin high and low in a loop, using a common ground for both. Will this work?

 

Yes, there is a very wide tolerance range on clock source.

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I have found that a microprocessor requires a decoupling capacitor to function. Hanging leads will not work. It is totally basic electronic design. Put a cap across the power and ground.

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Someguy22 wrote:
I have found that a microprocessor requires a (sic) decoupling capacitor 

Often (usually?) more than just one

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The adapter board trace lengths deter the correct use of bypass capacitors, near uC pins. Same with xtal connections. Seems a good design would have those parts on adapter, add a few more like ch340, and you would be closer to nano v3.0. I do not think parts are available for what nano can be purchased for. I bought 10 shipped, for under $23, they all work.

It all starts with a mental vision.

Last Edited: Mon. Dec 28, 2015 - 01:21 AM
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One of my current 1-off projects is battery powered: I use a Pro-mini for that.

To cut down current consumption, I removed the resistors which are in series with the on board leds.

If required, I can save a little bit more power by using the internal RC oscillator. The crystal (or resonator) can remain on board so I can always go back to crystal clock drive.
 

In post #16 you wrote:

 

So I actually went through all 10 of my ATMEGAs. And the very last one actually worked! It got programmed with no problems whatsoever. The bootloader was flashed successfully and I can actually use it to upload code.

No additional components were needed -- no bypass capacitors and no crystal. Not that I'm trying to prove that they're not needed, all I'm saying is that in my particular case it worked without them.

 

No crystal for the Arduino bootloader ? How is that possible ?

 

I think you need a good night sleep :) That clears the mind.

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joeymorin wrote:
Do I actually have to ask the questions?

Apparently. Because for the life of me I can't understand how will knowing the exact markings serve any cause.

Anyway, here are 9 of them: http://imgur.com/f0Dq1M6. The last one is soldered and working right now, but the numbers are identical to the last one in the picture.

 

KitCarlson wrote:
The adapter board trace lengths deter the correct use of bypass capacitors, near uC pins. Same with xtal connections.

Huh.. that makes sense.

 

KitCarlson wrote:
Seems a good design would have those parts on adapter

Which would make things like this "badly designed"? https://www.adafruit.com/products/1163

 

Plons wrote:
No crystal for the Arduino bootloader ? How is that possible ?

I think you need a good night sleep :) That clears the mind.

You ARE aware that an Arduino bootloader is just a code that runs before the "sketch" code, right? And that one of it's jobs is to present an easy way to program the MCU using serial communication, which Arduino IDE utilizes.

And if you DO know that, then why would you assume that the same serial communication is not achievable when MCU is running on an internal RC oscillator?

(granted, there might be synchronization issues because the communication is asynchronous and an internal RC oscillator is unstable without a crystal, but it's not something that can't be dealt with)

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for the life of me I can't understand how will knowing the exact markings serve any cause.

I guess you haven't been following?  Knowing the fab, lot, and date of manufacture can help you determine if there was a production flaw.  In fact, if you open a ticket with Atmel or the vendor (which I'd say it's clear by now you most certainly should), the first information they will ask for are the backside markings so they can confirm that what you received is what they shipped, and so they can track the part from the beginning of the manufacturing process through to delivery.

 

You still haven't answered the 64-million-dollar question:

joeymorin wrote:
Do the eight which don't work all have the same underside markings?

Who-me wrote:
zdazzy wrote:

8 out of 10 have the same code as in the picture. 2 have different ones.

... 2 of yours showed some signs of life, do they align with lots here ?

So the working one has the following markings:

A3FHYA

35473D

1-A

1518 e3

 

... and 7 others share that marking.

 

2 more have these markings:

A3GRWA

35473D

1-A

1529 e3

 

The first unit you tried worked at first (for initial programming), even though you've been unable to get it to work since.  Which markings does it have?

 

Whatever the answer is, it means that 6 or 7 of the 8 which share the same markings are not working, as are 1 or both of the other two.

 

All ten appear to have come from the same fab, but have different lots and date codes.  So the possible conclusions are:

  • problem at fab affecting lots separated by 11 weeks (unlikely)
  • problem across entire fab (very unlikely)
  • ESD damage during storage/handling/shipping

 

If you don't answer questions asked by those trying to help you, they will lose interest.

 

I've lost interest already anyway.  AFAIC, you've got your answer:

zdazzy wrote:
The atmegas arrived in the most ghetto package I've seen so far:

joeymorin wrote:
The greatest likelihood is that your cheap but perfectly legitimate AVRs have suffered cumulative and catastrophic ESD damage during the time they were in storage at the vendor, or during transit to or from their warehouse, or during handling and shipping to you.  Cardboard and scotch tape don't make good antistatic shipping materials.  Quite the opposite.  I would refuse any shipment which arrived without proper anti-static protection.

 

Best of luck.

"Experience is what enables you to recognise a mistake the second time you make it."

"Good judgement comes from experience.  Experience comes from bad judgement."

"Wisdom is always wont to arrive late, and to be a little approximate on first possession."

"When you hear hoofbeats, think horses, not unicorns."

"Fast.  Cheap.  Good.  Pick two."

"We see a lot of arses on handlebars around here." - [J Ekdahl]

 

Last Edited: Mon. Dec 28, 2015 - 06:35 PM
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zdazzy wrote:
Which would make things like this "badly designed"? https://www.adafruit.com/product...

 

NO! That "SMT Breakout PCB for 32-QFN or 32-TQFP" is not intended for a specific microcontroller, rather to breakout any 32-QFN/TQFP device for prototype development.

 

Stan

Last Edited: Mon. Dec 28, 2015 - 07:09 PM
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joeymorin wrote:
ou still haven't answered the 64-million-dollar question

No, there is no correlation between the 2 working chips and 2 with different set of markings. Both A3GRWA chips didn't work. The two working ones were A3FHYA.

 

joeymorin wrote:
AFAIC, you've got your answer

Seems like it. Thank you for you patience, I appreciate it.

 

sbennett wrote:
NO! That "SMT Breakout PCB for 32-QFN or 32-TQFP" is not intended for a specific microcontroller, rather to breakout any 32-QFN/TQFP device for prototype development.

My board is just a breakout board too and it can be used for the same devices.

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joeymorin wrote:
The greatest likelihood is that your cheap but perfectly legitimate AVRs have suffered cumulative and catastrophic ESD damage during the time they were in storage at the vendor, or during transit to or from their warehouse, or during handling and shipping to you.  Cardboard and scotch tape don't make good antistatic shipping materials.  Quite the opposite.  I would refuse any shipment which arrived without proper anti-static protection.

I agree. One big problem here from a practical point of view is -- how are you ever gonna be able to rule out ESD damage? You cannot. 

/Jakob Selbing

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Note that this is a 4-year-old thread that has be necromanced by @mariusz0 for no apparent reason.

"Experience is what enables you to recognise a mistake the second time you make it."

"Good judgement comes from experience.  Experience comes from bad judgement."

"Wisdom is always wont to arrive late, and to be a little approximate on first possession."

"When you hear hoofbeats, think horses, not unicorns."

"Fast.  Cheap.  Good.  Pick two."

"We see a lot of arses on handlebars around here." - [J Ekdahl]

 

Topic locked