I recently bought a pair of Uno R3 off AliExpress but when I tried to upload a sketch they both gave an out of sync error, it appears the bootloader is running at a slower baud rate, I changed the Uno to a Duemilanove and the sketch uploaded okay.
The crystal speeds on both types of board seem to be identical, the cpu doesn't have any markings on it but the pcb does state it is a LGT8F328 UNO R3.
I have uploaded the onboard LED sketch and that flashes at 4sec intervals not 1sec as programmed, would I benefit from uploading the bootloader from one of my other Uno's? or just use it as it stands.
Hi @malcolmgb. I'm sorry to hear you got one of these difficult to use Uno R3 derivative board where the Chinese manufacturer swapped in the cheap LGT8F328 chip instead of the standard ATmega328P we know and love.
This is because the clock on these boards runs at a different speed (4 MHz) than the clock on the Duemilanove (16 MHz). You should use a boards platform that is specifically made for the LGT8F328 boards instead of trying to use "Arduino AVR Boards" platform, which is for ATmega328P boards.
If you look closely at the product listing on Aliexpress, you will probably find a link or URL for one there. However, these are often low quality or difficult to install. I recommend instead using this nice community created "LGT8fx Boards" platform:
You can install it by following the instructions here:
After installing the platform, select Tools > Board > LGT8fx Boards > LGT8F328 from the Arduino IDE menus. After doing that, you will find that several new menus have been added under the "Tools" menu:
SERIAL_RX_BUFFER_SIZE
Clock Source
Clock Divider
Variant
Upload speed
It is possible you might need or want to adjust the settings under those menus, but hopefully the default settings will be OK for your board.
For now, I think it is best to leave it as is. The bootloader burning procedure is quite complex, so it should really only be done in cases where the board is unusable. I think you will find that once you switch to using the "LGT8fx Boards" platform, it will work as expected.
Thank you that has worked perfectly, I think a lesson learned there, look at what I am buying in future, I just expected a Uno to be a Uno, this electronics hobby is a little more complex than this old man realises.
Yeah. It can be very tricky with these boards because the sellers often intentionally advertise them as if they are just another normal UNO R3 clone.
The LGT8F328 chip is actually pretty interesting because, beyond the lower price, it has some features that the ATmega328P doesn't. However, the chip manufacturer did a terrible job at documenting and supporting the chip so it is quite a headache to try to do anything with it. Fortunately once you install the LGT8fx Boards platform, you should be able to pretty much just treat it as a normal Uno R3.
Thank you again Per, as you can see I am not knowledgeable about electronics just trying to keep my brain active in my old age.
As you said there are options in the IDE but have just left it with the defaults which is the fastest clock speed so that seems good.
Regards Malcolm