A guide for installing the tools necessary to build up a homebrew barebones Arduino Zero (based on the Atmel SAMD21G18A microcontroller) on a Linux PC. While this guide is written for a Debian-based distribution such as Linux Mint, it should be adaptable to other distributions fairly easily.
This guide also assumes that we will be using the ATMEL-ICE debugger to write the Arduino bootloader to the SAMD21G18A flash memory via the Cortex Debug Connector.
You'll need a recent version of the Arduino IDE which has support for the Arduino Zero in the Boards Manager. As of this writing, the latest stable version is 1.6.5, so be sure to use at least this version. Also as of this writing, the version of the Arduino IDE in the Linux Mint repositories is quite old, so don't use that one.
Go here to grab the latest version of the Arduino IDE, then simply uncompress the download to a convenient location and run the binary from that folder. Now navigate to the menu Tools > Board: > Boards Manager... and find the listing for "Arduino SAMD Boards (32-bits ARM Cortex-M0+)", select it, then click the Install button.
Now we need to set up some udev rules so that the ATMEL-ICE can run without superuser priveleges. Start by creating a new udev rules file:
sudo nano /etc/udev/rules.d/10-atmel-ice.rules
Paste this line into the editor:
SUBSYSTEMS=="usb", ATTRS{idVendor}=="03eb", ATTRS{idProduct}=="2141", GROUP="adm", MODE="0666"
Save and exit by pressing CTRL-O then CTRL-X.
Restart udev and then plug in your ATMEL-ICE:
sudo service udev restart
The ATMEL-ICE uses what is called a Cortex Debug Connector layout to do debugging and handle tasks such as writing flash memory. The standard connector size is a 10-pin (2x5) 0.05 inch header. This is what you will need to have on your target board so that you may program the Arduino bootloader into flash memory. Consult the SAMD21G18A datasheet for the wiring details of this connector.
Make sure that one end of your ATMEL-ICE programming cable is connected to the ATMEL-ICE via the SAM port, then connect the 10-pin connector on the other end of the cable to the Cortex Debug Connector on the target board, following the proper orientation of the connector. The ATMEL-ICE does not provide power to the target board, so be sure to provide the 3.3 V power that the SAMD21G18A needs. You'll see the green LED on the ATMEL-ICE light up when the target board has power.
Start up Arduino IDE, then go to the menu and select Tools > Programmer: > Atmel-ICE. Now you should be able to choose Tools > Burn Bootloader. If the bootloader was successfully written, you should see something like this in the console window (it will take a few moments to complete):
Open On-Chip Debugger 0.9.0-gd4b7679 (2014-10-03-00:26)
Licensed under GNU GPL v2
For bug reports, read
http://openocd.org/doc/doxygen/bugs.html
debug_level: 0
adapter speed: 500 kHz
adapter_nsrst_delay: 100
cortex_m reset_config sysresetreq
target state: halted
target halted due to debug-request, current mode: Thread
xPSR: 0x81000000 pc: 0x00002304 msp: 0x20007fd0
target state: halted
target halted due to debug-request, current mode: Thread
xPSR: 0x81000000 pc: 0x00000858 msp: 0x200023a0
** Programming Started **
auto erase enabled
wrote 16384 bytes from file /home/jason/.arduino15/packages/arduino/hardware/samd/1.6.0/bootloaders/zero/samd21_sam_ba.bin in 5.136203s (3.115 KiB/s)
** Programming Finished **
** Verify Started **
verified 6328 bytes in 0.666237s (9.276 KiB/s)
** Verified OK **
** Resetting Target **
shutdown command invoked
At this point, if everything has worked correctly, your barebones board should now function as an Arduino Zero (at least as far as the Arduino IDE is concerned).
I would recommend at a bare-minimum to have an LED connected to Arduino port D13 (SAMD21G18A pin 26/PA17) as is the custom in the official Arduino boards, so that you can use it for debugging purposes. Assuming that you have that, let's try to upload the Blink sketch from the Examples menu to verify that everything is working correctly.
Connect your barebones board to a USB port on your PC, then fire up the Arduino IDE. Select the Blink example sketch via menu File > Examples > 01.Basics > Blink. Now make sure that the proper board type is selected in the IDE. Choose Tools > Board: > Arduino Zero (Native USB Port), and then select the virtual COM port that your board enumerated under with the Tools > Port menu.
Now we should be able to upload the Blink sketch using the Upload button on the toolbar. If firmware loading is successful, you should see something like this in the console:
Sketch uses 11,076 bytes (4%) of program storage space. Maximum is 262,144 bytes.
Atmel SMART device 0x10010005 found
Device : ATSAMD21G18A
Chip ID : 10010005
Version : v1.1 [Arduino:XYZ] Jun 10 2015 11:08:10
Address : 8192
Pages : 4096
Page Size : 64 bytes
Total Size : 256KB
Planes : 1
Lock Regions : 16
Locked : none
Security : false
Boot Flash : true
BOD : true
BOR : true
Arduino : FAST_CHIP_ERASE
Arduino : FAST_MULTI_PAGE_WRITE
Arduino : CAN_CHECKSUM_MEMORY_BUFFER
Erase flash
done in 0.837 seconds
Write 11124 bytes to flash (174 pages)
[=========== ] 36% (64/174 pages)
[====================== ] 73% (128/174 pages)
[==============================] 100% (174/174 pages)
done in 0.091 seconds
Verify 11124 bytes of flash with checksum.
Verify successful
done in 0.044 seconds
CPU reset.
If the hardware is wired correctly, you'll see your LED toggle once per second, just like on an offical Arduino board. Congratulations!