Hello. I'm new here, so apologies if my query is inappropriate to this forum, or if my query should have been entered elsewhere in the forum.
Not only am I new to this forum, but I'm also new to Arduino. I bought a Uno R starter kit on eBay and have enjoyed working my way through various exercises.
More recently, I bought a Mega 2560 board which seems to work fine. However, I now realise that my board doesn't exactly resemble some of the other Mega 2560 boards advertised on eBay.
There appear to be two variants. One that resembles photos on a number of websites and in books I've seen. That one has a small group of header pins behind the USB connector. Then there's another, like mine, which does not have the header pins, but instead has what appears to be a surface mounted component in a metal 'can'.
Could someone please help me here, by clarifying whether or not there are more than one variants of the Mega 2560?
Thanks in advance for any help that you can provide.
Many thanks for your reply. I tried to attach a photo with my original post, but it was rejected. So I reduced the size, but it was rejected again, so I posted my message intending to try again later. You beat me to it! I've been out, but will now try again and also a close-up photo of the can as you requested.
Addendum
I keep getting "Your attachment has failed security checks and cannot be uploaded. Please consult the forum administrator."
Addendum
I have sent a DM to robtillaart asking how I should contact the forum administrator.
Addendum
The top of the can appears to be etched with the following ID :
12.QOOM 16
KQT 1337 3F
The metal can is the crystal for the CH340G USB-to-serial adapter. Your Mega 2560 is a derivative of the genuine Arduino Mega 2560.
There are also clones of the Mega 2560 on eBay. A clone is an exact copy of the genuine Arduino Mega 2560, except they are not supposed to use the Arduino logo. The clones and genuine Arduino brand boards are a little more expensive, because the ATmega16U2 chip is more expensive than CH340G.
Your derivative with the CH340G needs different drivers on your computer compared to the ATmega16U2. Since you are using it and it works fine, you have already installed the drivers.
You may see other derivatives which make use of alternative USB-to-serial adapters, such as FTDI chips. But the most common variant is the CH340G because it is extremely cheap.
Only advanced projects make use of the ATmega16U2 by programming it using the header pins behind the USB connector. Advanced users can do things like move the mouse cursor on the connected computer or simulate a keyboard and initiate keystrokes to the connected computer. Your CH340G is not programmable. If you don't plan to get into that sort of advanced use, you probably won't notice any differences between your board and a genuine or clone board.
dmjlambert:
The metal can is the crystal for the CH340G USB-to-serial adapter. Your Mega 2560 is a derivative of the genuine Arduino Mega 2560.
There are also clones of the Mega 2560 on eBay. A clone is an exact copy of the genuine Arduino Mega 2560, except they are not supposed to use the Arduino logo. The clones and genuine Arduino brand boards are a little more expensive, because the ATmega16U2 chip is more expensive than CH340G.
Your derivative with the CH340G needs different drivers on your computer compared to the ATmega16U2. Since you are using it and it works fine, you have already installed the drivers.
You may see other derivatives which make use of alternative USB-to-serial adapters, such as FTDI chips. But the most common variant is the CH340G because it is extremely cheap.
Only advanced projects make use of the ATmega16U2 by programming it using the header pins behind the USB connector. Advanced users can do things like move the mouse cursor on the connected computer or simulate a keyboard and initiate keystrokes to the connected computer. Your CH340G is not programmable. If you don't plan to get into that sort of advanced use, you probably won't notice any differences between your board and a genuine or clone board.
Many thanks for your very helpful reply. I understand now. For what it's worth you should be able to see two photos of my Mega 2560 board here https://flic.kr/s/aHskfWKHk3