I have just received some very cheap WAVCAT clones claiming to be Uno R3 boards.
They will not take a program unless I select Duemilanove as board type, and when I load the basic blink sketch they are running at a quarter speed, so a 1000ms delay pauses for 4 seconds.
Serial communication only works by selecting 2400 baud on the monitor, despite the sketch asking for the usual 9600.
Fitting an LCD shield works but appears to disable the D3 pin which I was happily using for ds18b20 inputs with all my other UNO clones.
So I don't have UNO R3, but what the heck are they? Is there anything I can do to make them usable or these just destined for the bin?
Has anybody else seen these before?
I guess they put 4 MHz resonator/crystals on them instead of 16 MHz? The workaround that comes to mind is to run off the internal oscillator at 8 MHz. I think that would be easier than making the Arduino IDE properly handle the 4 MHz clock since I don't know of an existing hardware package for that. Note that the internal oscillator is not as accurate and if it's way off this could cause problems with timing critical operations such as serial communication (and thus uploads).
It's pretty easy to change to the 8 MHz oscillator using MiniCore:
- Install MiniCore
- Connect an ISP Programmer to your target board. If you don't have a dedicated ISP programmer then you can use a spare Arduino board as an "Arduino as ISP" programmer.
- Tools > Board > ATmega328
- Tools > Variant > 328P / 328PA
- Tools > Clock > 8 MHz internal
- Tools > Programmer > select the appropriate programmer
- Tools > Burn Bootloader
Looks like this? Are there any legible markings on the bottom right crystal?
16x slow is usually a fuse error. (default: internally 8MHz Oscillator/8.) 2x slow is usually fuse error (internal 8MHz Oscillator instead of crystal.) 4x slow is weird!
(It's not promising that the store seems to be "WAVGAT" and the board is labeled "WVACAT", but I suppose that could be adequately explained by lack of familiarity with the roman alphabet.
Thanks for your responses pert and westfw , this has kept me scratching my head for too long already.
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The oscillator is 12.000mz, but I tried swapping it for a 16.00 with no change in speed! (Go figure, I wonder if the chip isnt accessing the oscillator at all, relying on the internal timer instead??)
Meanwhile I see the Chinese supplier has now posted some additonal LIBRARY and HARDWARE software to add to the Arduino IDE to make these things work like a UNO. That .rar file generated Parsing errors in Linux but eventually worked on an old XP laptop.
You then need to select board type Wavcat Uno and yes, it now runs blink at the expected speed. However it also seems to have swapped some pin configuration around at the same time as these boards no longer work with an LCD shield when programmed as Wavcat Uno.
Either way this board doesn't meet my expectations of a basic UNO, we shouldn't have to load additional drivers to make it work like all its clone cousins, it should be interchangeable with all other UNO clones. Proof that you get what you pay for.
Refund requested via AliExpress. I would advise others to give the Wavcat or Wvacat a miss if you value your time, pay another 20 pence for something that meets the standards.
The 12MHz crystal is probably for the USB chip. There should be a second crystal (or a tiny resonator) connected to the AVR.
There's a "compatible" chip to the M328 called the lgt8f328, that has some "improvements" like a 32MHz internal oscillator, DACs, 12bit ADC, and some other features. Perhaps you have one of those, that is incorrectly set up. (32MHz with div8 fuse would give you 4MHz?)
They apparently use a different programming technique than real AVRs, so fixing the fuses might be tough.
I've got a USBASP on the way from WAVGAT, I'll be interested to see what it is like when it turns up. Out of curiousity, what markings does the microcontroller have on it? Does it look like a standard ATMega328P?
westfw:
The 12MHz crystal is probably for the USB chip. There should be a second crystal (or a tiny resonator) connected to the AVR.
The picture you posted shows a 12 MHz crystal by the MCU as well as by the CH340.
Aren't crystals more expensive than ceramic resonators? Seems odd they would make that decision when Arduino uses the resonator on their official boards. I don't think I've seen a cheap clone with a crystal on the MCU before.
Minicore does 12 MH too.
Get yourself a Programmer and rebootload that thing.
4th picture down appears to show 328P
https://nl.aliexpress.com/item/Free-shipping-high-quality-UNO-R3-MEGA328P-CH340G-for-Arduino-Compatible-NO-USB-CABLE/32522378826.html
$2.85 and 32 cents to ship it. Who can compete with that?
Considering the low quality of most of the support packages I see from 3rd party board manufacturers, I'd definitely give MiniCore a try before messing with the package the seller provides.
4th picture down appears to show 328P
The same pictures that show 2 12MHz Crystals, right?
Alas, the ultra-cheap cloners can't at all be trusted not to have cloned the pictures as well.
(Interestingly, they're no longer cloning "real" Arduinos. They're cloning each others "cheaper" circuit.)
Yes, both crystals are 12.00mhz. The chip is marked MEGA328P AU1736. On the appearance it looks as though it has all the usual components on board (except that others use a 16mhz), so why would they have gone to the trouble of writing revised software if it just needed the correct bootloader. Does this indicate they have made a bad copy of a clone and devised a partial workaround?
I tried and failed to change the bootloader using another good UNO as programmer, just couldn't get it to take it.
even worse: on the boards I got MISO and MOSI are not connected to the 6-pin SPI header, which is named SWD.
I also got punished with those WVACAT boards. As I hated to extend the list of installed boards I appreciated the idea of Solarpeter declaring them as Duemilanova boards.
Upload works, Serial speed divide by 4 o.k.
But the EEPROM library doesn't work, you keep getting random results.
Don't know if it works when you install the rar library provided.
So I better (mis-)use it for some silly LED installation and never ever order one of these again.
I got caught with this piece of junk thinking it was UNO compatible. The xtal is marked at 16 mhz however as others have said the Blink sketch runs quarter speed. Alo the lcd key pad shield doesn't work so I'm glad it only cost around $3. I may investigate or put it down to experience.
I was doomed with some of these clones... the ADC is 12bit indeed, and you can revert to 10bit with calling
analogReadResolution(10)
from setup. But the ACD is very noisy and returns very imprecise values.
Has anyone here managed to get i2c or SPI to work with this arduino ? With i2c it just hangs during setup...
I have some experience with the LGT8F328P board from WEMOS:
The LED is on Pin 12 (MISO) and the board is bigger than the original NANO V3 and has other layout (Pins,...).
I had made a DDS-function generator with an 1602 display and rotary encoders. Because of the 32 MHz the sine is going up to more than 20 kHz (Atmega328P about 10 kHz).
I have tested an ILI9341 SPI grahic display (240x320) . It was only going with ucglib:
not with adafruit gfx ...
ILI9341 is running also with UFTLIB (SW-SPI), but slow.
I have tested also the Nano LGTF328P clone ,
[url=https://www.ebay.de/itm/1pc-LGT8F328P-LQFP32-MiniEVB-For-Arduino-Nano-V3-0-HT42B534-1-Replace-ATMeag328P/183767606852?hash=item2ac9672644:g:0LcAAOSwMnZcrFkH[/url]
but with no positive results.
cyberponk:
I was doomed with some of these clones... the ADC is 12bit indeed, and you can revert to 10bit with callinganalogReadResolution(10)
from setup. But the ACD is very noisy and returns very imprecise values.
Has anyone here managed to get i2c or SPI to work with this arduino ? With i2c it just hangs during setup...
There are different clones...
The most boards from WAVCAT use a real ultra low cost clone and you can only use it with the WAVCAT board components inside the Arduino. The code is not compatible and the chip is also not compatible, but they write ATMega 328, even if it isn't an ATMega. The most people reports that it is so bad, that you can't use the most functionality of the real ATMega and it can't reach 4MHz.
And then, there is the LGT8F328P. This seems to be a good clone and is not from WAVCAT (they just use it). It has a 12bit ADC, 32MHz, a unique ID and also a DAC pin. I never had one.
For those who are still reading this discussion in 2020.
dbuezas make a great job on it.
And thanks to Ralph S Bacon for his wonderful introduction. 
In my own case, I bought 20X LGT8F328P at a unit price of $2.8 CNY.
Then made a six-way fan controller. It works fine.