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Topic: Overvoltage on 3.3V - Duemilanove dead or just parts? (Read 4831 times) previous topic - next topic

SteelWolf

Dec 31, 2012, 02:07 pm Last Edit: Dec 31, 2012, 03:46 pm by SteelWolf Reason: 1
Hi,
I accidentally shorted the 3.3V pin to the 12V VIN
It draw about 500mA for several seconds.
I don't know which part got warm but it was arround the main voltage regulator.
My question now:
Is it completely dead or just parts? (5V reg, atmega..)
The program that was previously stored won't work, RX and TX flicker some times when I try to upload a program and the software says:
after binary sketch size:
avrdude: stk500_getsync(): not in sync: resp=0x00
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51

Do I have to buy a new one or is it repairable?

Edit: The Loopback test fails. Only the Rx led flickers.
The PC recognizes it and beeps.

Edit2:
Im a student with limited budget, the best would be if its just the atmega.. but I can't afford the time to order again if something different is broken :/

Im from Austria, does somebody know where to get the single ATMEGA 328 with arduino? (If its the right type?)
I don't have an IDE, whats the simplest way to burn a fresh atmega?
Aaaand if its probably not the atmega thats dead, where do I get a new duemilanove? (because this one was a present :/)

Thanks,
Max

CrossRoads

You probably killed the FTDI chip, which is the source of the 3.3V on the Duemilnove. Not an easy part for a novice to replace.
Your best bet may be to unsolder the part anyway you can, and then use an external USB/Serial interface connected to the same pins (Rx, Tx, +5, Gnd and DTR)
such as
http://www.nkcelectronics.com/breakout-board-for-ft232rl-usb-to-ser232.html
http://www.nkcelectronics.com/ftdi-basic-breakout.html
or this with a slight mod
http://www.ebay.com/itm/CP2102-USB-2-0-to-UART-TTL-6PIN-Module-Serial-Converter-/130683943875?pt=LH_DefaultDomain_0&hash=item1e6d5ebbc3
(cut trace going to RST header pin, add jumper from DTR hole to the pin instead)

Check farnell.com for Austria for parts, ATmega328P-PU.
You will need an AVR ISP to program a bootloader, or a sketch with no bootloader, onto a part.
This one is pretty inexpensive when they are back in stock, or if you can find a local source.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

SteelWolf

#2
Jan 01, 2013, 08:25 pm Last Edit: Jan 01, 2013, 08:27 pm by SteelWolf Reason: 1
Hi,

Thanks for the answer!
The problem is that I don't have a hot-air soldering station :/
Maybe I can modify my hot-air blower to try desoldering the ftdi chip cleanly.
I'm a bit afraid trying to desolder it with my normal solder-station

I have one ftdi module here. But I guess its not the right one.
But if it is, can i just connect the pins directly to the "breakout pins" or do I have to solder them to the FTDI chip pins (Are the 5V, TX, RX the same as for the chip)
The FTDI board (DLP-USB232M) has TXD and RXD but also TXN and TXL

Is there a chance that the atmega survived and "only" the ftdi is dead?
I think I have to buy a hot air station..

PS: I have a source for the atmegas.. but they don't have ISPs for them :/ A friend of mine got an arduino nano. Can i burn the atmega with the second arduino? If yes, is there a good instruction somewhere?

Grumpy_Mike

Quote
Can i burn the atmega with the second arduino?

Yes.
Quote
is there a good instruction somewhere?

http://arduino.cc/en/Tutorial/ArduinoISP

SteelWolf

Hi,
thanks! That was what I was looking for.. I will test it tomorrow if I'll get and arduino until then.

Buuuuut I now removed the Atmega and tried the loopback test again
Now it echos everything back in the serial monitor!
So I guess its not the FTDI?
Im a bit confused..
If the FTDI is not broken.. what else could be damaged? and why is the atmega blocking the echo?

CrossRoads

You could try snipping the legs next to the body with really small cutters and touch each leg with a soldering iron and lift it off with tweezers.  I think cutting the legs could tricky, I don't think I have small enough cutters to do that even.
If you have a small dental pick kind of tool, you can try heating/lifting one leg at a time.
Use some magnification and be patient.

You need about 300C-315C for 30 seconds to heat the legs enough to lift the part.

What FTDI module do you have? Post a link.
You should be able to connect to the Rx, Tx, Reset, 5V, Gnd pins on the headers.

There's a good chance the rest of the board is fine, the 3.3V is isolated from the rest of the board by the FTDI chip.

"I have a source for the atmegas.. but they don't have ISPs for them".. What does the 2nd part of this mean?
You can use an arduino to put a bootloader on a 2nd arduino.
Look at File:Examples:ArduinoISP, connect as listed.
http://arduino.cc/en/Tutorial/ArduinoISP

Also look at  NickGammon's page
http://www.gammon.com.au/forum/?id=11635

Late edit: Since loopback is working, perhaps FTDI chip is only partially damaged.
Try putting in a different uC chip.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

SteelWolf

http://www.dlpdesign.com/usb/usb232.shtml is the FTDI module.
But since the loopback is working, do I have all the functionality of the FTDI that I need?
I just don't see how the overvoltage could have destroyed the atmega but not the ftdi?
And how exactly can the ATmega stop the loopback from working?

I meant that I have a shop that sells the right ATmega type but no ISP for the atmegas in stock.
(If I can't get the second arduino until tomorrow I would have a bought an ISP)

Grumpy_Mike

Quote
I just don't see how the overvoltage could have destroyed the atmega but not the ftdi?

Why not? Chips do not expire at the same time when suffering abuse.

Quote
And how exactly can the ATmega stop the loopback from working?

Simply by holding the pins at a fixed level.

CrossRoads

"do I have all the functionality of the FTDI that I need?"

Perhaps. Is the 3.3V output still good? Can see the output with a meter. Connect an LED with current limit resistor for 20mA to Gnd, see if it lights up. Or two in parallel for 40mA, maybe a 3rd for the full 50mA.

Is the DTR output still working? That's a tougher one to check, as it normally sits at 5V and briefly dips to Gnd (0.4V or so) to create a reset.
Can connect it to Reset on another board (Gnds also) and see if plugging in the USB cable creates a reset on the good board.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

SteelWolf

#9
Jan 01, 2013, 11:48 pm Last Edit: Jan 01, 2013, 11:51 pm by SteelWolf Reason: 1
I don't need the 3.3V, is it essential to test if it delivers enough current?
The 3.3V has 3.30V and the 5V pin arround 4.92V

Its a bit hard to capture the DTR, its normally on.

When I plug in USB (and use it as power) it quickly changes to 5V.. no idea if there is a reset between : /
I guess I have to connect a seperate supply to test it.

@ Grumpy_Mike:
What i meant is that the FTDI is the only chip that was directly connected to the 3.3V pin and it still works.. but the atmega behind it propably not.

CrossRoads

I suppose the 12V could have backfed thru the FTDI chip and got out onto the 5V supply line to fry the Atmega.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

SteelWolf

#11
Jan 07, 2013, 09:11 pm Last Edit: Jan 07, 2013, 09:23 pm by SteelWolf Reason: 1
Ok,
so I got a new Atmega816
And a Arduino Nano from a friend.
I connected everything like it would be 2 Duemilanove.
I also added an 120Ohm resistor between 5V and reset because many instructions connected this error mesage with the auto reset:
avrdude: stk500_getsync(): not in sync: resp=0x15

And thats exactly my problem.
I get this error message about 4 seconds after I press burn with "arduino as isp"
The L led shortly flashes on the Duemilanove (The One that has to be programmed)
I choose the right target board and also uploaded the ISP to the right board.
The "to be programmed" board is powered via the 5V from the nano.

I really hope that it was just the atmega thats broken.
But again,
RX / TX works when jumpering it and removing the atmega.
And everything has the right voltage.

I hope someone can help me
Thanks!

Edit:
I removed the resistor and added a 10µF cap between gnd and reset on the NANO (ISP arduino)
Now i get this error message:

avrdude: Expected signature for ATMEGA168 is 1E 94 06
         Double check chip, or use -F to override this check.

SteelWolf

#12
Jan 08, 2013, 02:20 am Last Edit: Jan 08, 2013, 03:53 am by SteelWolf Reason: 1
Mpf..
I accidentaly bought and Atmega8-16
not and Atmega168..
Altough they are pretty pin compatible this one won't fit in the Duemilanove, or would it?
The problem is that I now have absolutely no source for the 168 in Vienna.

I now read another bunch of threads and many end with the solution to burn it with an external programmer.
The problem is that I also can't get one in the next week, but that would be very important. :/

I guess will now start to implement the Arduino Nano into my project, as damage reduction. Altough I have to create new "shields" for it.



CrossRoads

See if these guys will ship to you

http://www.taydaelectronics.com/catalogsearch/result/?q=atmega
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

SteelWolf

Altough this needs 7-12 working days, this seems to be a very attractive site.
They also have a -15% discount coupon on their facebook site until tomorrow jan.9, just for info.
I will definately order some atmegas on stock there.
(Still need to find a source for the next days, but I think I can forget that)

Thanks!

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