The Arduino Mega is a great board. You can often get a project that typically requires multiplexing or shift registers running with a single Mega board because it contains so many GPIOs. The only problem I have with it is its massive size. Enters Robotdyn shrunk versions, and for about US$7!
Shop webpage: https://www.aliexpress.com/store/1950989
The Mega 2560 Pro “Embed”
The Mega 2560 Pro Embed is simply put a fully compatible board with the Arduino Mega 2560, with all the features, shrunk into a tiny 38x55mm footprint. And that, in itself, is trully amazing.
The USB controller is a CH340G, a proven chip; and the onboard voltage regulators are of the AMS1117 series (one for 5V, the other for 3.3V). Not the best components out there, but they are definitely adequate for the job.
Out of the box, the Arduino IDE programmed the chip without any issue. In my opinion, it is the Mega you should get if you need an Arduino with many pins. Easy to use, efficient, small sized. It’s a great board!
The Mega 2560 Pro Mini
Now the Pro Mini is where things get interesting.
This board uses the same design as the embed, except it doesn’t contain a USB controller. As a result, it doesn’t have a 3.3V regulator, and no USB connection. You program it using a Serial to USB adapter; just like the normal Arduino Pro Mini based on the ATMega328P. Those smalls differences makes the board 3mm slimmer, and the board as such is truly the king of Arduino board to create a permanent project. This board is so bare it is almost a breakout board for the ATMega 2560 chip.
Programming this Arduino, as a result, is slightly more complicated. During my initial test I used a FT232RL FTDI USB to TTL adapter (a very common serial to USB chip), but it failed to load a program. In fact, the Pro Mini does not recognize the CTS/DTR signals and requires a simple reset signal. This is NOT a very popular standard so be careful. Robotdyn’s USB to TTL UART CH340 board works well; and it costs less than a dollar.
The package: what do you get?
You can get the boards and nothing else, but I recommend spending a few cents more and getting the header pins with it. The Pro Mini comes with all the necessary pins, plus a 2×6 for ICSP and 5 straight pins for UART. The Embed is exactly the same, without the UART pins.
Size comparison
There is little left to say about these Arduino clones. But a picture is worth a thousand words right? Here’s a shot of these new Mega compared to the original Arduino Mega, together with an Arduino Uno for comparison:
That’s right: you can get all the pins of a Mega for a smaller footprint than an Uno!
Conclusion
If you are hesitating on the Mega because of its humongous size: think again! These 2 boards fill the gap in the Arduino offering, and became defacto one of the best 8 bit AVR based Arduinos money can buy.
Verdict: Good
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13 thoughts on “Robotdyn’s Mega Pro Mini and “Embed” Arduino boards review”
Hi,
I am a fan of RobotDyn also — great quality, quick delivery and well packaged!
Recently I bought two of these boards and a both CH340G based serialUSB adaptors, which RobotDyn offers.
Using Linux (CH340G driver already part of Linux) I cant read or write a single byte through the adaptors.
I failed to flash the MEGA2560 with this adapters.
What do you mean with “Serial connection of the Pro Mini is non standard: careful.” — Is this the reason for my failure?
Thanks for any help in advance!
Hi mcc,
All that serial port specify is that you must have a TX and RX line, that’s all. But you need additional lines on these sorts of programmers, typically a reset signal. Most adapters use a DTR signal that’s from the RS232 standard, but that’s not the case for these Arduino boards: they just need a reset signal.
The CH340G offered by Robotdyn SHOULD work, since it’s what I used in the end and it was working perfectly. To be precised I used that one: https://www.aliexpress.com/item/CH340G-5V-USB-to-TTL-UART-Serial-Converter/32524218818.html.
Switch TX/RX and try again?
Another option is to upload “Arduino as ISP” sketch on a Uno board and use the ICSP header.
Hi Tony,
Thank you for your reply! 🙂
I am using the whole stuff on Linux (no windows here).
I bought both CH340G converters made by RobotDyn including the one you linked. None works. They act as isolators…nothing is read nor written.
I connected TX with RX !on the converter itsself! (loop-back-test) … nothing. For ICSP/ISP-programming I am using my buspirate … works fine. But
I want to include an USB interface with the Mega2560 into the casing for my Nixie-clock. Accessing the RESET-bottom for each update of the firmware
is also a least wanted “feature” for that clock.
What OS are you using?
Cheers
mcc
Yeah seems like a good idea… I regret encasing my nixie clock without leaving an access to the ICSP/serial headers.
It seems like your issue is more related to the CH340G though, do you have any board with the CH340G on the board itself (e.g. not from these USB adaptors – like the “mega embed”) to confirm it? I did all my code on Windows 10, so I can’t help you there.
It’s also entirely possible you have a faulty board (happened to me once, couldn’t load a program) but since you have two of them with the exact same issue, and the ICSP method works, chances that it is a hardware issue are slim to none.
Hello,
Could you finally solve the issue? Im on the same situation. I have two MEGA 2650 PRO MINI 3.3V and both Robotdyn ch340s and I cant upload any sketches. I can upload it using a USB CP2102, making a manual reset before to uploading but there is no way using the robotdyn ch340! I bought original Robotdyn usb-ttl thinking that from same maker it would to works propertly with its boards but not for me. Im going crazy this issue. I have looked out on internet about this board but I there is barely information about this board. I hope you could help me. Thank you in advance.
Regards
The 2560 Pro is important for one reason: The 3.3v gpio option.
There are lots of modules that are 3.3v, and the 2560 has too many IO pins for you to throw a level shifter at it.
As for the Reset, I too couldn’t get the Reset pin to trigger with any UART adapters with an exposed reset pin. So what you have to do (If you’re using Arduino) is mash the red reset button just before the progress bar hits completion. I would say wait one second after hitting ctrl-U before double-clicking the reset button.
It’s been crazy trying to get this to work, but apparently legitimate Mega2560 r3 boards have this same problem for some reason.
And an update: I have an inline capacitor that connects between the 2560’s reset pin and my UART’s DTR pin. I think it’s 0.1uF. That will reset your 2560 appropriately to kick in the programming phase of the bootloader. This is a small trick I learned (years ago) after banging my head against the wall trying to get an old UART OLED screen to start up.
Hmmm. Amazon has a lot of reviews talking about malfunctioning modules. Have you encountered this too? My module is corrupting what should be a const char array! 🙁
When i compare the pin layout of the Arduino Mega2560 Pro Mini, and the version of Robotdyn, i see differences !!
In the “Original” Mega2560 Pro MIni version a see a gap between A14/A15 and D32/D33 holding the Reset and Aref Pins…
In the Robotyn version, the pins are not on this place of the PCB. They are on the other side of the PCB
So if i have a already designed PCB for Arduino Mega250 Pro Mini, i have a problem !
So its NOT 100% pin-compatible !
Hello Cor, which version of the “original” Mega 2560 Pro Mini are you referring to? Arduino does not produce a mini board of the Mega 2560 as far as I know.
Hi guys, I’ve bought both of them and I’m trying to use them as Joystick but I’m struggling to understand how can I use them as HID. Is there someone that could give me some advice. Thanks
I think your bootloader isn’t working correctly.
Because the analogue pins and the timers they work accordingly. Please check those once
I was referring to mini mega2560 the with CH30 chip
I just got the RobotDyn Mega 2560 (without USB) and I cannot program it at all. I also got the Robotdyn CH340 but it still doesn’t work. How did you solve this?