XIAO SAMD21 - Smallest Arduino Microcontroller with Rich Interfaces for Wearable Devices, 100% Arduino IDE Compatible, 3pcs

I bought 3 of these a couple years ago to play around with. At the time, it was just because they were cheap and quick to get on Amazon. I quickly fell in love. Though they aren't perfect. Pros: Size. They're tiny. Even 2 years on, most microcontrollers are *at least* 2 to 4 times the size. The small size makes them easy to fit into almost any project. They're literally the size of a postage stamp. I can cover one with my finger. Which brings me to the next pro: I/O. Even at this tiny size, you still have tons of I/O, with support for hardware interrupts, UART, I2C, SPI, and true analog pins with DAC. The big one for me, though, is HID support through the USB type C port. That's a much less common feature than you'd think. If you want to make devices that can talk to other devices as an input device, you need this. Speed. You don't really think that a simple Arduino device needs to be fast, but having a 48mhz processor and 32mb of SRAM to work with open up a LOT of possibilities. Take, for example, my most recent project. I wanted to make a vintage laptop keyboard work with a modern laptop motherboard. But I wanted to do so without damaging the original keyboard. So to interface the two, I needed the Xiao to be able to read the PS/2 protocol that the keyboard was talking in, and give USB HID protocol commands to the computer. Reading the PS/2 protocol takes very precise timing. Your code has to execute within a certain number of microseconds, otherwise the command will fail. Because of the speed of the processor, I could have more code executing in the interrupts while still staying under the threshold. Cons: Storage. While I've never run up against the limit, the Xiao has 256 kB of flash memory. That's not the smallest, but it's certainly not the biggest I've seen on a microcontroller. So I do get a little nervous when I start importing a bunch of libraries. So far, my most involved project, the keyboard that I talked about earlier, only uses about 25% of that storage. And that's importing two different libraries plus my custom code. But if you have a large project that takes many libraries or a whole lot of code, you might run into problems with storage. Bootloader Corruption. I've only had it happen once and it was after hundreds upon hundreds of code uploads. These guys saying they're bricking after 50 uploads have to be doing something wrong. Or maybe it's because they're on Mac hardware, I don't know. But I've had to upload 50 times pretty much everyday I've worked on this project and so far it's not been a problem. But like I said, I did have one of my original three stop responding to USB. So the problem does exist. The device itself still does what the last upload of code told it to do, but I can no longer get it to talk with the Arduino software. And resetting the unit didn't resolve it. So you're mileage may vary.

This tiny microcontroller is great for small projects. Actually, it's quite powerful for what it is and has plenty of I/O pins. My son uses it for Star Wars props and Cosplay. It's great for wearables, controlling LEDs, and just about anything an Arduino can do but just more. The setup can be a little confusing at first, but the documentation on the SeedStudio site is really good. It will walk you through with setting up the Arduino IDE or setting up Circuit Python, since the setup is very different from each other. I've programmed this little microcontroller with both the Arduino IDE and with Circuit Python. Circuit Python might be more beginner friendly. I really like that it has USB Type-C connector because then I can use the same cable as my Mobile Phones. It's annoying to have so many different cables around. One thing to make note is that these microcontrollers are not 5v tolerant. Yes, you can power it with 5 volts, but the inputs and outputs are 3.3 volts. The one thing I wish it had was a reset button, but it's so small I'm sure it would be impossible to fit. You can add a reset button because there are soldering pads for it, but it doesn't have one on the board it self. So, if you are making wearables this would be great. Actually, you can use it to control servos, led light strips, and a ton more. It even has a DAC so you can technically make it produce sound too!

Very good Stamp sized controller. Best in the series, the ESP32S3 chip is one of the best performers. My application involved an I2S interface to a microphone and four RMT interface outputs to SM2812B leds. Issue #1: The 3.3v regulator on this board has fluctuating output and I need to run my microphone on a separate regulator or I can 'hear' the CPU processing as noise in the microphone. Other arduino boards do not have this issue. The oscilloscope revealed that this chip makes it's power rails rather noisy! Issue #2: Pin 7 (GPIO43) has a part on it that makes the bandwidth poor. This pin isn't usable for high bandwidth control. It's a design choice on their part. Darn good board. Five stars.

The Short Version: A great little chip, powerful, well supported, I use many different microcontrollers for various projects but this one has quickly become my favorite. A Bit Deeper: Pros: Fast, With its higher than average 48Mhz over the common 16Mhz I don't see nearly as many micro timing issues during complex operations or while using multiple interrupts Reliable, so far the only problem I have encountered is normal and easily remedied a simple double reset to get back to the boot loader Flexible, With digital and analog sharing almost the entirety of the I/O interface circuit integration is simple, along with I2C, UART, SPI, And a Built in 3.3v DAC, it really is rich with connectivity for such a dense package Resource Friendly, this little guy seems to eat almost nothing... really I could measure it and blah blah but.... Cons: 3.3v logic only, only really been a problem once or twice more of a hitch in the plan not very difficult to get past but it can be a pain on occasion No big Brother: this ones personal, I would love to see a one set up chip like this guy with a bit more I/O for projects requiring more connectivity, But there's other microcontrollers of course

Very satisfied with the purchase, all 3 SAMD21 board tested and confirmed working. I will be able to prototype easily with these spare boards

Super petit très content : ) !

商品説明の写真にははんだ付けされたピンが付いているが 届いた物にはピンが付いていなかった。付属すらしていない。 返品するにも時間がもったいないからピンは自分で付ける。 SeeeduinoXIAOは悪くないけどSHOPがダメ。

I really like this tiny board for its quick processor and large memory. It’s awesome for small projects or wearables. I did have some trouble getting started with it because I am still a Windows 7 user. Minimum system requirements is W10. After some searching I did find an unsigned driver for W7/8 that worked, but you have to manually install it. Once past that hurdle I got the board working on the Arduino IDE (1.8.8). The next challenge because of the Samd21 architecture was finding out which Arduino libraries were compatible. I managed to make work: FastLED, RC-Switch, Adafruit RTC, and u8g2 to drive a SSD1306 0.96” OLED display. I tried to make the Adafruit SSD1306 and Adafruit GFX libraries to work for the OLED but had compiling errors, so you might have to find alternatives for certain libraries. Next thing is something I have seen several here complain about: bricking the board. I ran into this situation where it locked up and became a unrecognized USB device. The solution I found was very simple… double short out the reset solder points until the orange LED on the board fades in and out, which puts the board into bootloader mode. Now it will show up as a USB storage device in windows, then in the Arduino IDE check the port shows XIAO and it checked off and hit “upload” again. This will unbrick the board and make it function normally again, provided you have fixed your program error that made it freeze up in the first place. Other then that amazing board that I have been able to upload to over and over and over again without any failure. Hope this information helps others.O

The SAMD21 device have some sort of bug where you can upload a new program to them a few times, and it's somehow no longer listening, so the uploader times out. This doesn't affect CircuitPython because that's not the same kind of upload. I'd love to see a fix for this so I can relentlessly send changes to it without issue.