boards/saml21-xpro: update board documentation

Signed-off-by: Dylan Laduranty <dylan.laduranty@mesotic.com>

boards/saml21-xpro/doc.txt

@@ -55,18 +55,19 @@ indiscriminately;
 
 | Device | ID        | Supported | Comments  |
 |:------------- |:------------- |:------------- |:------------- |
-| MCU        | saml21    | partly    | PLL clock not implemented |
+| MCU        | saml21        | yes    |  |
 | Low-level driver | GPIO    | yes       | |
-|        | PWM       | no            | |
+|        | PWM       | yes       | |
 |        | UART      | yes       | |
 |        | I2C       | yes       | |
 |        | SPI       | yes       | |
-|        | USB       | no        | |
+|        | USB       | yes       | |
 |        | RTT       | yes       | |
 |        | RTC       | yes       | |
-|        | RNG       | no        |  |
+|        | RNG       | yes       | |
 |        | Timer     | yes       | |
 |        | ADC       | yes       | |
+|        | DAC       | yes       | |
 
 
 
@@ -74,17 +75,13 @@ indiscriminately;
 
 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 OpenOCD.
+The standard method for flashing RIOT to the saml21-xpro is using [edbg](https://github.com/ataradov/edbg).
-Please note that even the latest official OpenOCD (v0.9 at the time of this
+by calling: `make BOARD=saml21-xpro -C tests/leds flash`
-writing) does not support B-variant SAML21 devices.
 
-If you attempt to flash a board, and OpenOCD throws a `Couldn't find part
+Note that on Linux, you will need libudev-dev package to be installed.
-corresponding to DID XXXXXXXX` error, you will need to compile your own OpenOCD
-from source.
 
-Refer to https://github.com/RIOT-OS/RIOT/wiki/OpenOCD for general
+Users can also use openOCD to flash and/or debug the board using:
-instructions on building OpenOCD and make sure "cmsis-dap" and "hidapi-libusb"
+`PROGRAMMER=openocd make BOARD=saml21-xpro -C tests/leds flash`
-are enabled.
 
 On Linux you will have to add a **udev** rule for hidraw, like
 ```
@@ -97,6 +94,7 @@ 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"
@@ -107,24 +105,6 @@ 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
 
-## Supported Toolchains
-
-For using the saml21-xpro board we strongly recommend the usage of the [GNU Tools for ARM Embedded Processors](https://launchpad.net/gcc-arm-embedded)
-toolchain.
-
-
 ## Known Issues / Problems
 
-### Stack sizes
-The default stack sizes have not been tuned properly yet. If in doubt why
-your application crashes try increasing the default stack sizes and use `ps` to
-find out how much stack is being used.
-Tracked in https://github.com/RIOT-OS/RIOT/issues/2228
-
-### Not flashable by OpenOCD anymore
-It can happen that OpenOCD is not able to program the board, because of wrong
-clock configuration or low power modes. In this case you can use
-[this little tool](https://github.com/ataradov/edbg) to erase the flash. Just follow the
-instructions to build it and run `./edbg -e` to erase the flash. Then press the
-reset button and you're able to program via OpenOCD again.
  */