[Edit: just hooked up logic analyzer and I see it's actually 5 times a second] I thought that led should blink once a second. If that is true then there is something wrong with this board and I will return it. I have tried everything to get a sketch to upload with no luck, including a few dozen manual reset attempts. The RX led blinks 3 times but the TX does not blink when I try uploads. The chip looks fine when I hook up the USBisp and read the flash and fuses. I can see there is a sketch loaded on it, but I suspect the 200ms blinking is not from the sketch. It is an R3 I bought on Ebay, looks genuine Arduino but I suppose it could be a knockoff. My op system is Win7. Windows says my driver is up to date, for what that's worth.
Anyone know if 5 blinks a second sounds like a bad board?
I'm confused, you mix the bootloader with the sketch.
The clone boards from Ebay are very cheap, but I have to repair 1 in 5.
Do you have a programmer, and can you upload a sketch using the programmer and the 6-pin ICSP header ?
This example:
arduino.cc/en/Tutorial/Blink
sets the led on for a second and off for a second.
When you use the programmer to upload it, the bootloader is overwritten. After that you have to rewrite the bootloader.
If it flashes 5 times a second, the sketch is not running. It might be in a reset loop.
After rewriting the bootlader, you should be able to upload a sketch using the USB plug.
If that is not working, the board might be broken.
The bootloader itself will flash the LED 3 times "rapidly" when the bootloader first starts.
A board that is flashing the LED rapidly and continuously may just be completely empty except for the bootloader, which would cause the bootloader to run over and over again.
From my post "The chip looks fine when I hook up the USBisp and read the flash and fuses. I can see there is a sketch loaded on it,"
I even used a byte by byte compare utility to compare what my USBisp/asp read from the chip with the optiboot.hex file for the Uno .. It compares exactly except for the last line. I hesitate to try downloading a sketch with SPI because I don't want to erase the bootloader. If the board is bad, I should return it unmodified. I might try that though, and if it doesn't work, I suppose i could put the original bootloader and sketch back on it because I did save it to file.
I have to assume, from what you guys posted, that this board is bad and I probably should return it because there is a pretty good chance that I will never be able to upload sketches via the USB or use USB Serial.
You can try to upload a sketch via the ICSP header. That is perfectly normal to do.
After that, rewrite the bootloader, using the Arduino IDE. That way you have also the newest bootloader, which is also good. The Arduino IDE even sets the fuses to the right values when you rewrite the bootloader.
If avrdude can connect to the ATmega chip with the ICSP header, you don't have to hesitate to upload sketches and bootloaders.
There is one small note. If you have a clone with the ATmega328 chip instead the ATmega328p chip (with a 'P'), you might get into trouble. The Arduino IDE for the Arduino Uno board want the ATmega328p chip.
If you have the ATmega328p, go for it. Don't bother about 'original' bootloader, the Arduino IDE is the original software.
I bought my first Arduino (an Uno r3) on Ebay, From an outfit in Florida for $29.95. That I later found as an "Authorized" Arduino reseller.. The real giveaway is the Price IMO... The fakes are always in my limited (3 Year) experience quite a bit less than the ++$20.00 "Real" Price that a "Genuine" product sells for... I buy fakes... but I do realize that doing so is a crap shoot (crappy shot?) and I use them for well defined task's that I have proven on a known genuine part.. Simply because the final price is within the project budget...
Caveat Emptor is simply Good Sense.. There is ALWAYS a reason for "Cheap"
pegwatcher:
It's black and golden, but after very careful scrutiny, I find it's a fake, albeit a very good one.
How do you determine that?
Pictures, please!
It is interesting to see a new fake.
The black-and-gold polyfuses were custom made for Arduino. If they appear on fakes, it will mean that the fakers have realized the difference, and adjusted accordingly.
Here's a major fake-alert! The component 501 K located next to the voltage regulator is generally green on fake boards. The green one has similar properties as the original Arduino golden-black component and is available off the shelf.
We get it specially made for Arduino to make it look different:
I compared mine with the pictures on this site: http://arduino.cc/en/Products/Counterfeit
Mine is very close to the Real Arduino but it fails to pass a few comparisons, especially the character font.
BTW I did load a sketch on mine with USBasp and the board works fine, including Serial Monitor. I then put the Optiboot on it but still cannot upload via USB. Tried manual reset dozens of times, but never get a peep out of the TX pin, only activity is on the RX. I suspect the driver. I have never tried a Uno on this laptop until just now. Win7 auto installed a driver as soon as I plugged the new Uno in, but I have to wonder if it's the correct one. I am away from my desktop for the winter and using a laptop, instead of the desktop I had used with the old (now dead) (reference to company selling counterfeit boards removed by moderator) Uno.
I am searching for info/help about drivers for the R3. I removed the driver using DEVICES & PRINTERS and then intended to manually install the driver that came with 1.0.5 but Windows re-installed a driver without giving me the chance. I don't know if they installed the one that came with the 1.0.5 distribution, or what. ( I really hate Windows)
Peter_I, I will try to put up a picture of my board tomorrow so you can see a really good fake. It is very late where I live and I will call it a day now..
Got a couple pretty good pictures of front and back of the counterfeit Uno but even though my camera shows up in Devices and Printers, when I try to transfer from my camera to the laptop, I only get "Cannot detect camera". I have transferred to this laptop dozens of times in the past.
Something is amuck with this laptop. Whatever, maybe it's related to not being able to upload to Uno via USB
westfw:
I've always found that particular claim a bit unbelievable. "Not normally stocked at xxx distributor", perhaps. "Custom made" - no way.
Oh dear! So these are in fact, merely standard Bourns Polyfuses, in the case of the "501K" cited, a MF-SM(D)F050, 550 mA batch made at the start of March 2011 (or was that 2001?), or my "500Z", presumably made at Christmas 2010.
Or did Arduino acquire whole batches so that the codes would be unique? Here's a question (if it hasn't been asked before) - what batch numbers of the genuine gold polyfuses do people have?
I dunno. If Bourns is the only one who sells the gold/black parts, and all the "clone" manufacturers clone/use the other company's (littlefuse, TEC, etc) green fuses, then it's still a pretty good indicator. If the clone vendors all bought the high-quality components from the expensive vendors, then the clone wouldn't be cheap... (presumably "let's plate our contacts with gold, but still sell them for cheaper" is not a phrase you hear very often.)
I have a Duemilanove and MEGA1280 with 508S, and a more recent MEGA-ADK with 501L.