what kind of current does it pull? How well does it sleep?

If anyone is looking for a debug header, part# 20021111-00010T4LF from FCI looks like a good candidate. Also, I highly recommend the Atmel-ICE debugger, for those going beyond the Arduino IDE.

The integrated Lipo charger might make me use this rather than the Teensy LC/3.1/3.2 on my next project - but I so do love the teensy. It would be interesting to see them benchmarked/compared. Come on Sparkfun, how about it??

[EDIT] 2/24/19 I found the messages below answering this question[/EDIT]

Apparently this board can now be run on CircuitPython. I have found lots of tutorials on how to run CircuitPython, and how to install CircuitPython. The problem is, all installations for SAMD21 boards are for Adafruit products. I have even found a .UF2 file for this exact board. What is missing is instructions on how to get this .UF2 installed on this board. It shows up as a USB device with a port assigned, but never as a USB drive. All instructions on using Arduino to install are for an .ino file that can't be found anywhere.

So, how can I install CurcuitPython on the Sparkfun SAMD21 mini Breakout?

Hi, can you explain how the Q2 p-channel mosfet works connected between USB power and Vin? Seems like just a fancy diode to ensure USB power flows only one way. I don't understand what the gate does.

MicroPython? Not the copied circuitpython ... please? Sparkfun?

Is the SAMD21 Mini breakout available with CircuitPython or MicroPython pre-installed? Or, if the python option is not available to order, which tutorial should be followed to get UF2 and python working on this sparkfun board?

I dont see a 48Mhz crystal on the board nor in the schematics but only a 32.768khz one. Is the 48Mhz crystal internal?

I love these little boards!! I have bought at least 20 of these little buggers! they are the perfect size and power for a lot of projects. unfortunately in the last two batches i bought, four of them were missing the arduino bootloader. I was in communication with sparkfun support and confirmed this was the issue. (2 out of 8, and then 2 out of 5 of the next batch). so be careful! otherwise try to get a hold of a J-link programmer and do this manually!

I saw that this chip has a built in capacitive touch controller for up to 256 channels. Has anyone got more information about how I would use this functionality with the Arduino IDE, and even how this would be possible in terms of number of pins?

I downloaded the bootloader from github, but it doesn't build with the latest (1.8.2) Arduino toolchain. I've modified the paths in the Makefile but some fields in drivers/cdc_enumerate.c don't quite match up. It looks like you guys started with an old version of the Atmel bootloader code and then modified it. I think I can modify your cdc_enumerate.c with the code from the latest Atmel AT07175, but it might be easier to just go back to the Arduino toolchain you originally built this with. Do you remember which version of the toolchain you used?

I purchased this mini-breakout for the SAMD21 to determine if I can use it as basis of a development board for my embedded systems class. Since I want students to purchase the parts and assemble their own boards, I need them to use a Bootloader, not purchase their own Atmel ICE (they will use the department ICE once to flash the Bootloader). I ran into a lot of problems making this happen that I want to share with you so that you might not have to struggle as I did. First, the SAM-BA 2.16 utility in its current configuration is not usable, at all because it only allows you to flash .bin files starting at address 0x6000. Meanwhile, the bootloader you flash to the SAMD21 (with your ICE) assumes that the user program starts at address 0x1000 or 0x2000 depending on which you flash. You need to get yourself the SAM-BA 2.15 utility which Lars over at AVR freak generously uploaded here. *Second, since the SAM-BA 2.15 utility only allows you to flash a user program starting at address 0x2000, you will need to flash the USART/USB combined bootloader onto your SAMD21 using the ICE. This combined bootloader assumes that user program will be flashed to address 0x2000. *Third, in Atmel Studio you will need to compile your code so that it targets address 0x2000. To do this select Project -> Options -> Toolchain -> ARM/GNU Linker -> Miscellaneous and add: * -Wl,--section-start=.text=0x2000 at the end of the Linker Flags list. *Fourth, you need to ground out "pin 5" on the SAMD21 breakout when pressing the reset button. This will boot the SAMD21 into bootloader mode allowing the SAM-BA 2.15 utility to talk to the SAMD21 bootloader. I am probably forgetting several things, but this list should save you several hours. If you know of a version of the SAM-BA 2.15 or 2.16 utility that allows a user to flash to address 0x1000, I would be much obliged if you would provide a link. I hate wasting the 0x1000 bytes of memory on a kludge, but I am not in the mood to recompile the SAM-BA utility.

I added support to the Microsoft UF2 booloader for this board. See https://github.com/Microsoft/uf2-samd21 and https://github.com/Microsoft/uf2-samd21/pull/17.

This repository contains a bootloader, derived from Atmel's SAM-BA, which in addition to the USB CDC (serial) protocol, also supports the USB MSC (mass storage).

You can build it with make BOARD=sparkfun-samd21-mini

Hi All, I tried Standby Mode using this RTCZero library. I have also removed the Power LED and supplies 3.3V directly at 3.3V pin (by passing LDO). I'm getting current in range of 300uA which is Okayish.. considering ATsamD21 can go down to 10uA. Can someone suggest what else I can try?

1. Is this due to Hardware of Sparkfun board?
2. Is there something can be done in RTCzero library to decrease Stand by Current

Please advice..

Does anyone have ann code for standby and sleep mode? I got the standby to work, but not able to og to sleep mode.

My Projects needs the sleep mode current to be low.

I just bought this mini breakout and I need to run 6 analog devices on it (4 gas sensors and 2 photocells). The specifications say there are 14 ADC lines, but the board only has A0 - A3 labelled. How do I get access to the other ADC lines? Where are they physically on the board and how do I reference them in the Arduino IDE? Thanks!

I am trying to write a program for this using atmel studio but the program never seems to start. I am uploading it by taking the .bin file atmel studio generates and using bossac. If i generate the bin file with the Arduino IDE, it works so theres some initialization I'm missing. Is there some startup code I need to setup?

Here is the program I am trying to run:

int main(void){
    SystemInit();
    REG_PORT_DIR0 |= PORT_PA17;
    REG_PORT_OUT0 |= PORT_PA17;
    while (1){}
}

The power-up reset doesn't seem to work. Is this expected? If we download a simple blinky light sketch it runs as expected if the USB cable is connected. If we power the board using 5V on VIN the sketch doesn't start unless the reset button is pressed.

Hi!How can I upload an Exported bin sketch (from Arduino IDE ) to the SAMD21 mini ?

I have Atmel Studio 7 and the Atmel Ice?Is there any particular setting ?

FreeRTOS

How easy is it to run FreeRTOS on this or the FreeRTOS port that was ported to arduino on this? Does anyone have any experience?

Downloading programs to the Mini Breakout was going very slowly, unlike my Arduino Zero. I've updated the boot loader and now the Mini Breakout downloads fast. (I can program a boot loader into a SAM D21 myself with a modified Arduino Zero board)

Is there any plan to add this to platformio? It looks like the following file will need to be updated: https://github.com/platformio/platformio/blob/develop/platformio/boards/sparkfun.json (Hmmm... it's probably more complicated than just updating that file...)

does anyone working with this mini breakout or arduino zero succeed in interfacing with low cost 0,96" or 1,3" OLED display in any combination of driver SSD1306 or SH1106 and with any graphic libraries

thanks Davide

Does anyone has a good Eagle library (.lbr) file for this nice breakout ? thanks Davide

This mini breakout board is small and powerfull. Love using it.

As a note I edit the variant files on the sparkfun board to give me Serial 2 and Serial 3. Dont need them right now but good to have. I have tested these Serials and thay are working.

All info can be found on Sparkfun Forum. Link: https://forum.sparkfun.com/viewtopic.php?f=32&t=42698&p=186984&hilit=SAMD21+Serial2#p186984

Nice little board but, increasingly, I find that such low pin count devices are becoming less and less useful for my projects especially with all the pin sharing current microcontrollers do. By the time you use a few of the on-board peripherals you end up with very few/no GPIOs. Teensy 3.2, the Pro Mini, this board all fall into this category. I love Teensy because of it's M4 processor but the board layout/pinout is a challenge.

Anyway I'd find this board much more attractive if it used a ATSAMD21J18 and was lengthened to accommodate the additional pins (8 per side). The 16 additional I/O's would make it much more flexible and useful for a larger number of projects. Is there a marketing reason backed up by actual data that says you have to stick to so close to the Pro Micro /Teensy form factor ?

In the graphical datasheet, PA14 is marked as I2C-capable. However, the Atmel datasheet does not mark this pin as I2C-capable. (It seems no PAD2 or PAD3 pins are I2C capable, actually.)

Does this board support an external analog reference when using the Arduino IDE? When I try the following: analogReference(EXTERNAL); I get an error: "invalid conversion from 'int' to 'eAnalogReference"

Ordered two of these, and although I'm not 100% sure, it looks like the SPI port that is implemented is not the default one that is used by the Arduino IDE.

The Zero schematic suggests that the SPI port on pins: PB10, PB11 and PA12 is the default. Perhaps someone can confirm?

Also, the RX/TX map to what is essentially the "second" serial port; SERIAL1. PB22 and PB23 are the default SERIAL0. The schematic suggests that SERIAL0 is connected to the EDBG header, but it's not clear which pins would be used.

What spacing are the 5x2 header pins? What is the part number for Break Away Headers for the 5x2 pins?

Note: The breakout does NOT have headers installed and will need to purchased and soldered on yourself. Check the Recommended Products section below for the type of headers we use in the Hookup Guide!

All the headers in the referenced document are .1 inch spacing and the 5x2 arrays appear much smaller than .1 spacing.

I have the SD card connected with pin 9 as the chip select. Sam won't initialize the card. All I did was pop out the pro mini 3.3v and popped this in the board. Code compiles and downloads but won't initialize card. The pro mini had no issues with the SD on my board.

I'm curious about the overhead/efficiency of the power regulation on board. Will this work if I plug a lipo (3.7-4.2v) into VIN? Does it have the same DC-DC converter and LDO voltage regulator pair that the Zero has?

Basically I want to run this for 7 days from a 2500mAh lipo, which I think works out to an average current of 13mA. I'm hoping to make heavy use of standby mode to accomplish this, but I'm worried about "station keeping" components such as the regulator(s).

Unfortunately, the SparkFun SAMD21 Mini Breakout doesn't breakout the SPI header, used by the arduino SPI library.... :-( What about that ?

I wish I had known about this a couple of months ago! :) I am totally going to start using this Micro in all of my projects, especially since it has 256K of storage space and hardware serial on different pins.

Hrm, I was hoping this would be a step up from the Teensy 3.2, but it seems to fall a bit short instead. Mainly in terms of RAM (half) and CPU speed (2/3)

This would be an awesome board to have a one or two 5V outputs (similar to the Teensy LC, but the 8k ram is too limiting for many of my needs), so that you don't need separate level shifters when using 5V hardware like WS2811 LEDs.

It's really cool. What about the bootloader? Is it necessary upload a previous bootloader to the ATSAMD21G18? Thanks!

Very interesting, this will really help in creating one's own ARM solutions and provides a solid base to build those on. Thanks SFE!

This is awesome! Would have loved to have had this for a project I was working on a few years ago.