Seeed Studio 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.

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 Xiao was easy to setup in my Arduino IDE. Once I installed the correct "Board" in "Board Managers", I was able to upload code to the chip. Worked great.... for a day. Then the board stopped responding to USB. I'm not sure if it was a bad batch or what happened. It was promptly replaced with a new one. So far so good. I will update a review in the replaced purchase item listing. These boards are a great way to implement controllers, into a tiny project case. UPDATE: The new board works great. Have had no problems. I would highly recommend this board to anyone that needs a microcontroller that fits into a small project enclosure. I will be buying more, for future projects.

I can't comment on alot of the specific ins and outs of the product because I've yet to run anything other than a blink test sketch to confirm that they work with Arduino and are functional, all 3 were! Like I mentioned in the title, this product has alot going for it: Price: $21.99 for 3 of them so..roughly(rounded up from $7.3) $8 per controller! That's $1-$2 less than Adafruit's Trinket M0 which features the same hardware but does include an RGB LED. I'll take price-to-performance value over a stupid RGB light any day! Size: They are tiny! Perfect for permanent installation onto a breadboard/protoboard or even a PCB(They have castellated edges so you could indeed SMT solder these with the proper technique and good paste/equipment) Specifications: Very good for something so small. SAMD21(Cortex M0) @ 48MHz w/ 256K of Flash! ** I will say that I would've liked to see(and would've paid an extra dollar or two) an external Flash chip, maybe a 1MB or 2MB size? Adafruit does this in their larger boards and premium products in order to accomodate CircuitPython, they don't have external/extra flash on the Trinket M0(Which this is comparable too), so maybe its simply a size thing. ALTHOUGH, I think they could've easily fit a 1-2MB SOIC Type flash chip on the bottom of the pcb. Overall, a great buy for anyone on a budget or with limited funds thats looking for some bang out of their buck!

Packaging substandard. Plastic bag, piece of pink antistatic material on the pins. This was thrown in Amazon envelope with other items and no additional protection. Somehow this one ended up with the pink material compressed a bit and one of the corner pins really bent. I’ll straighten it to test but likely will replace that header for the final project.

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!

Absolutely a great value. Not a shill here, but I'm happy to say these are by far some of the best value micro controllers you can be get. I mean, 32 bit and you get 3 for $20 (I'm a prime member and you get them for $19.79 for the 3 pack), what a deal. Now, granted you don't get as many I/O pins, but if you're interested in a controller that truly is tiny and reliable, this is your board. They're also Arduino compatible. You will have to download a new library, but it's not that hard. Go to the Seeeduino website and scroll down really far and it'll show exactly what you need to do to get them working with the Arduino IDE. Some of the instructions may be a little out of date, but they're still useful. In Arduino go to preferences and then boards. You'll need to paste a.link to have the boards added to the IDE. Then search for the "Seeeduino" library. It should say something like Seeeduino boards or something like that. They recently consolidated the library into one. If it's taking long to download, that's the one, you're not doing anything wrong. Then, just plug it in (did I mention it's USB C! yay! Buy a cable or 3 if you don't have one, they're cheap), click verify and upload, it should pop up like a USB stick, do some stuff and then it'll disappear. It'll seem like something went wrong, but it should work. If not, try loading a different example sketch or change a value like making the led flash faster. The default/preloaded code is the blink sketch so change the 1000 to say 100 so you'll be able to tell if it worked. Happy coding!

No timer, makes it completely useless for what I got it for :-(... error: #error Internal code configuration error, no timer functions implemented for this CPU / board 2255 | #error Internal code configuration error, no timer functions implemented for this CPU / board Sigh, won't even run blink example: efm32s2_dci_read_se_status Error: unable to find a matching CMSIS-DAP device Failed uploading: uploading error: exit status 1 Oh well, will feed the parts bin and maybe someday find another use for it :-( :-( :-(. Never mind, when the rest of them get here I'll return them all. Added later.... After spending the better part of two days trying every fix I could find I had NO LUCK. Avoid this Piece Of Crap... Only good news is that Amazon refunded the cost :-). Unfortunately not the hours wasted trying to get these things to work. Great joy hammering them into tiny pieces and then tossing that into the trash, although the toilet would be more appropriate, but I suspect they would screw up the toilet :-).

This is a great little board. You will need to solder the header pins as it clearly shows their not connected so just know that. I've been abusing this one pretty hard and its been handling it fine. Im actually very impressed with it and will likely buy more. Compact size is great too for smaller projects.

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。

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.