Atmel SAM L21 Xplained Pro

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When using this board with RIOT, set the BOARD variable to saml21-xpro in your Makefile. If you follow the standard RIOT project structure, your Makefile should look like this:

# name of your application
APPLICATION = hello-world

# Change this to your board if you want to build for a different board
BOARD ?= saml21-xpro

# This has to be the absolute path to the RIOT base directory:
RIOTBASE ?= $(CURDIR)/RIOT

include $(RIOTBASE)/Makefile.include

Support for the Atmel SAM L21 Xplained Pro board.

Overview

The SAML21 Xplained Pro is an ultra-low power evaluation board by Atmel featuring a ATSAML21J18A SoC. The SoC includes a SAML21 ARM Cortex-M0+ micro- controller. For programming the MCU comes with 32Kb of RAM and 256Kb of flash memory.

The saml21-xpro is available from various hardware vendors for ~50USD (as of oct. 2015).

Please note: ATMEL’s most recent SAML21s are the B variant, or ATSAML21J18B. Because the driver changes are mostly small, throughout this reference the device will continue to be referred to as the ATSAML21J18[A/B] indiscriminately;

Hardware

saml21-xpro image

MCU

MCU	ATSAML21J18A
Family	ARM Cortex-M0+
Vendor	Atmel
RAM	32Kb
Flash	256Kb
Frequency	up to 48MHz
FPU	no
Timers	8 (16-bit)
ADCs	1x 12-bit (20 channels)
UARTs	max 6 (shared with SPI and I2C)
SPIs	max 6 (see UART)
I2Cs	max 6 (see UART)
Vcc	1.8V - 3.6V
Datasheet	Datasheet
Board Manual	Board Manual

User Interface

1 User button and 1 LED:

Device	PIN
LED0	PB10
SW0 (button)	PA02

Implementation Status

Device	ID	Supported
MCU	saml21	yes
Low-level driver	GPIO	yes
	PWM	yes
	UART	yes
	I2C	yes
	SPI	yes
	USB	yes
	RTT	yes
	RTC	yes
	RNG	yes
	Timer	yes
	ADC	yes
	DAC	yes

Flashing the device

Connect the device to your Micro-USB cable using the port labeled as EDBG.

The standard method for flashing RIOT to the saml21-xpro is using edbg. by calling: make BOARD=saml21-xpro -C tests/leds flash

Note that on Linux, you will need libudev-dev package to be installed.

Users can also use openOCD to flash and/or debug the board using: PROGRAMMER=openocd make BOARD=saml21-xpro -C tests/leds flash

On Linux you will have to add a udev rule for hidraw, like

bash
echo 'KERNEL=="hidraw*", SUBSYSTEM=="hidraw", MODE="0664", GROUP="plugdev"' \
    | sudo tee -a /etc/udev/rules.d/99-usb.rules
sudo service udev restart

Arch Linux

With yaourt:

yaourt -S libudev0
yaourt -S hidapi-git
yaourt -S openocd-git
# edit PKGBUILD, add "cmsis-dap hidapi-libusb" to "_features"

Ubuntu

Although this refers to setting up the SAMR21, this guide is still very helpful to understanding how to set up a solid RIOT development environment for the SAML21: http://watr.li/samr21-dev-setup-ubuntu.html