diff --git a/Documentation/platforms/arm/samd2l2/boards/xiao-seeeduino/index.rst b/Documentation/platforms/arm/samd2l2/boards/xiao-seeeduino/index.rst
new file mode 100644
index 0000000000000..5c35151b2a3c8
--- /dev/null
+++ b/Documentation/platforms/arm/samd2l2/boards/xiao-seeeduino/index.rst
@@ -0,0 +1,138 @@
+========================
+Seeed Studio Xiao SAMD21
+========================
+
+The `Seeed Studio Xiao SAM21 `_ is the first of the XIAO family, and is a
+general purpose, low-power and tiny board. It can be referred to as the "Seeed Studio Xiao SAMD21" or the "Xiao
+Seeeduino".
+
+.. figure:: seeed-xiao-samd21.jpg
+ :align: center
+
+Features
+========
+
+* ATSAMD21G18A-MU microcontroller chip @48MHz
+* 256KB flash
+* 32KB SRAM
+* 14 pins (11 analog, 11 digital)
+* 10 PWM interfaces
+* 1 DAC output pin
+* Serial wire debug interface
+* 1 I2C interface
+* 1 SPI interface
+* 1 UART interface
+* USBC interface
+* Serial communication indicator LEDs for TX and RX (blue)
+* Power indicator LED (green)
+* Blinkable LED (yellow)
+
+Serial Console
+==============
+
+By default, the serial console appears on the board's UART interface. Pin 9 is
+TX and pin 7 is RX.
+
+Pin Mapping
+===========
+
+Pins are numbered anticlockwise from the USB connector.
+
+===== ======== ========================================
+Pin Signal Notes
+===== ======== ========================================
+0 PA2 A0/D0/DAC
+1 PA4 A1/D1
+2 PA10 A2/D2
+3 PA11 A3/D3
+4 PA8 A4/D4/SDA (I2C)
+5 PA9 A5/D5/SCL (I2C)
+6 PB08 A6/D6/TX (UART)
+7 PB09 A7/D7/RX (UART)
+8 PA7 A8/D8/SCK (SPI)
+9 PA5 A9/D9/MISO (SPI)
+10 PA6 A10/D10/MOSI (SPI)
+11 3V3
+12 GND
+13 5V You can supply 5V power on this pin too.
+===== ======== ========================================
+
+There are also four pads on the back side of the board. SWCLK, SWDIO for serial
+wire debugging, and RST and GND for resetting the board. These same two pins are
+also exposed on the top of the board.
+
+Power Supply
+============
+
+The board can be powered through a USB-C connection. It can also be supplied 5V
+power through it's 5V power pin.
+
+There is an additional two pads for powering the board (VIN and GND) on the back
+side. The board accepts anywhere between 3.3V and 5V.
+
+Installation
+============
+
+To build NuttX for the Xiao Seeduino, you can use the following configuration
+commands within the cloned ``nuttx`` repository:
+
+.. code-block:: console
+
+ $ ./tools/configure.sh xiao-seeeduino:nsh
+ $ make
+
+This will generate a ``nuttx.hex`` file. To put the program on your board, you
+can choose from one of the following:
+
+1. Convert the hex file to a uf2 file using the `Microsoft uf2 tool `_:
+
+ .. code-block:: console
+
+ $ git clone https://github.com/microsoft/uf2.git
+ $ cd uf2/utils
+ $ python uf2conv.py -f 0x68ed2b88 -b 0x2000 nuttx.hex -o nuttx.uf2
+
+ Then, plug your board into the host computer using the USB-C interface. Short
+ the RST (reset) pad with ground twice in a row quickly. The board will be
+ detected as mass storage under the name "Arduino", and its orange LED will be
+ pulsing slowly. You can then copy the UF2 file to the drive/storage device
+ which appears. Once the file is done copying, the board will auto-eject and
+ you will have an NSH console on the UART pins!
+
+ .. todo::
+ Maybe this process should be part of the post-build scripts, since the
+ Microsoft UF2 tools is MIT licensed.
+
+2. Flash the hex file using the ``bossac`` tool. You can find the source for it
+ `here `_, or you can install it on Arch
+ Linux via the AUR with this command:
+
+ .. code-block:: console
+
+ $ yay -S bossa
+
+ Then, plug your Seeduino in via USB-C to the host computer and short the RST
+ (reset) and ground pins twice in a row quickly. The board will be detected as
+ mass storage under the name "Arduino", and its orange LED should be pulsing.
+ You can then run the following command:
+
+ .. code-block:: console
+
+ $ sudo stty -F 1200
+ $ sudo bossac -i -d --port= -i -w -v nuttx.hex -R
+
+ .. todo::
+ The ``bossac`` utility doesn't actually work for programming in my testing
+ yet. It is what the Arduino IDE uses but I haven't managed to get the
+ commmand line working. Using the commands listed above does actually
+ detect the board but the programming itself fails with "Flash command
+ failed". This needs more debugging.
+
+Configurations
+==============
+
+nsh
+---
+
+Basic NuttShell configuration with the console enabled on the UART interface at
+115200 bps. Comes with "Hello world" demo.
diff --git a/Documentation/platforms/arm/samd2l2/boards/xiao-seeeduino/seeed-xiao-samd21.jpg b/Documentation/platforms/arm/samd2l2/boards/xiao-seeeduino/seeed-xiao-samd21.jpg
new file mode 100644
index 0000000000000..c0e6a12b1a997
Binary files /dev/null and b/Documentation/platforms/arm/samd2l2/boards/xiao-seeeduino/seeed-xiao-samd21.jpg differ
diff --git a/boards/Kconfig b/boards/Kconfig
index e98058c9e6a65..c123b7729c3d9 100644
--- a/boards/Kconfig
+++ b/boards/Kconfig
@@ -2329,6 +2329,15 @@ config ARCH_BOARD_SAMD21_XPLAINED
This board features the ATSAMD21J18A MCU (Cortex-M0+ with 256KB of FLASH
and 32KB of SRAM).
+config ARCH_BOARD_XIAO_SEEEDUINO
+ bool "Seeed Studio XIAO SAMD21"
+ depends on ARCH_CHIP_SAMD21J18A
+ select ARCH_HAVE_LEDS
+ ---help---
+ The port of NuttX to the Seeed Studio XIAO SAMD21 board.
+ This board features the ATSAMD21J18A MCU (Cortex-M0+ with 256KB of FLASH
+ and 32KB of SRAM) in a tiny footprint.
+
config ARCH_BOARD_SAME54_XPLAINED_PRO
bool "Atmel SAME54-Xplained Pro development board"
depends on ARCH_CHIP_SAME54P20
@@ -3467,6 +3476,7 @@ config ARCH_BOARD
default "sama5d4-ek" if ARCH_BOARD_SAMA5D4_EK
default "samd20-xplained" if ARCH_BOARD_SAMD20_XPLAINED
default "samd21-xplained" if ARCH_BOARD_SAMD21_XPLAINED
+ default "xiao-seeeduino" if ARCH_BOARD_XIAO_SEEEDUINO
default "same54-xplained-pro" if ARCH_BOARD_SAME54_XPLAINED_PRO
default "saml21-xplained" if ARCH_BOARD_SAML21_XPLAINED
default "sam3u-ek" if ARCH_BOARD_SAM3UEK
@@ -3945,6 +3955,9 @@ endif
if ARCH_BOARD_SAMD21_XPLAINED
source "boards/arm/samd2l2/samd21-xplained/Kconfig"
endif
+if ARCH_BOARD_XIAO_SEEEDUINO
+source "boards/arm/samd2l2/xiao-seeeduino/Kconfig"
+endif
if ARCH_BOARD_SAME54_XPLAINED_PRO
source "boards/arm/samd5e5/same54-xplained-pro/Kconfig"
endif
diff --git a/boards/arm/samd2l2/xiao-seeeduino/Kconfig b/boards/arm/samd2l2/xiao-seeeduino/Kconfig
new file mode 100644
index 0000000000000..2d9fa0fa92197
--- /dev/null
+++ b/boards/arm/samd2l2/xiao-seeeduino/Kconfig
@@ -0,0 +1,12 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+if ARCH_BOARD_XIAO_SEEEDUINO
+
+menu "XIAO Seeeduino"
+
+endmenu # XIAO Seeeduino
+
+endif # ARCH_BOARD_XIAO_SEEEDUINO
diff --git a/boards/arm/samd2l2/xiao-seeeduino/configs/nsh/defconfig b/boards/arm/samd2l2/xiao-seeeduino/configs/nsh/defconfig
new file mode 100644
index 0000000000000..e961f34749069
--- /dev/null
+++ b/boards/arm/samd2l2/xiao-seeeduino/configs/nsh/defconfig
@@ -0,0 +1,59 @@
+#
+# This file is autogenerated: PLEASE DO NOT EDIT IT.
+#
+# You can use "make menuconfig" to make any modifications to the installed .config file.
+# You can then do "make savedefconfig" to generate a new defconfig file that includes your
+# modifications.
+#
+# CONFIG_DISABLE_POSIX_TIMERS is not set
+# CONFIG_NSH_DISABLEBG is not set
+# CONFIG_NSH_DISABLESCRIPT is not set
+# CONFIG_NSH_DISABLE_CMP is not set
+# CONFIG_NSH_DISABLE_DD is not set
+# CONFIG_NSH_DISABLE_EXEC is not set
+# CONFIG_NSH_DISABLE_EXIT is not set
+# CONFIG_NSH_DISABLE_GET is not set
+# CONFIG_NSH_DISABLE_HEXDUMP is not set
+# CONFIG_NSH_DISABLE_IFCONFIG is not set
+# CONFIG_NSH_DISABLE_ITEF is not set
+# CONFIG_NSH_DISABLE_LOOPS is not set
+# CONFIG_NSH_DISABLE_LOSETUP is not set
+# CONFIG_NSH_DISABLE_MKRD is not set
+# CONFIG_NSH_DISABLE_PS is not set
+# CONFIG_NSH_DISABLE_PUT is not set
+# CONFIG_NSH_DISABLE_SEMICOLON is not set
+# CONFIG_NSH_DISABLE_UNAME is not set
+# CONFIG_NSH_DISABLE_WGET is not set
+# CONFIG_NSH_DISABLE_XD is not set
+CONFIG_ARCH="arm"
+CONFIG_ARCH_BOARD="xiao-seeeduino"
+CONFIG_ARCH_BOARD_XIAO_SEEEDUINO=y
+CONFIG_ARCH_CHIP="samd2l2"
+CONFIG_ARCH_CHIP_SAMD21J18A=y
+CONFIG_ARCH_CHIP_SAMD2X=y
+CONFIG_ARCH_STACKDUMP=y
+CONFIG_BOARD_LOOPSPERMSEC=3410
+CONFIG_BUILTIN=y
+CONFIG_DEFAULT_SMALL=y
+CONFIG_EXAMPLES_HELLO=y
+CONFIG_HAVE_CXX=y
+CONFIG_HAVE_CXXINITIALIZE=y
+CONFIG_INIT_ENTRYPOINT="nsh_main"
+CONFIG_INIT_STACKSIZE=1536
+CONFIG_INTELHEX_BINARY=y
+CONFIG_NSH_BUILTIN_APPS=y
+CONFIG_POSIX_SPAWN_DEFAULT_STACKSIZE=1536
+CONFIG_PTHREAD_STACK_DEFAULT=1536
+CONFIG_RAM_SIZE=32768
+CONFIG_RAM_START=0x20000000
+CONFIG_RR_INTERVAL=200
+CONFIG_SAMD2L2_SERCOM4=y
+CONFIG_SCHED_WAITPID=y
+CONFIG_START_DAY=18
+CONFIG_START_MONTH=10
+CONFIG_START_YEAR=2024
+CONFIG_SYSTEM_NSH=y
+CONFIG_TASK_NAME_SIZE=0
+CONFIG_USART4_RXBUFSIZE=64
+CONFIG_USART4_SERIAL_CONSOLE=y
+CONFIG_USART4_TXBUFSIZE=64
diff --git a/boards/arm/samd2l2/xiao-seeeduino/include/board.h b/boards/arm/samd2l2/xiao-seeeduino/include/board.h
new file mode 100644
index 0000000000000..961bf6a0e5101
--- /dev/null
+++ b/boards/arm/samd2l2/xiao-seeeduino/include/board.h
@@ -0,0 +1,410 @@
+/****************************************************************************
+ * boards/arm/samd2l2/xiao-seeeduino/include/board.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __BOARDS_ARM_SAMD2L2_XIAO_SEEEDUINO_INCLUDE_BOARD_H
+#define __BOARDS_ARM_SAMD2L2_XIAO_SEEEDUINO_INCLUDE_BOARD_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include
+
+#ifndef __ASSEMBLY__
+# include
+# ifdef CONFIG_SAMD2L2_GPIOIRQ
+# include
+# endif
+#endif
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Clocking *****************************************************************/
+
+/* Overview
+ *
+ * OSC8M Output = 8MHz
+ * `- GCLK1 Input = 8MHz Prescaler = 1 output = 8MHz
+ * `- DFLL Input = 8MHz Multiplier = 6 output = 48MHz
+ * `- GCLK0 Input = 48MHz Prescaler = 1 output = 48MHz
+ * `- PM Input = 48Mhz CPU divider = 1 CPU frequency = 48MHz
+ * APBA divider = 1 APBA frequency = 48MHz
+ * APBB divider = 1 APBB frequency = 48MHz
+ * APBC divider = 1 APBC frequency = 48MHz
+ *
+ * The SAMD21 Xplained Pro has one on-board crystal:
+ *
+ * XC101 32.768KHz XOSC32
+ *
+ * REVISIT: Not currently used, may want to use as GCLK1 source with
+ * DFLL multiplier of ((48000000+16384)/32768) = 1465 which would yield
+ * a clock of 48,005,120 MHz.
+ */
+
+/* XOSC Configuration -- Not available
+ *
+ * BOARD_XOSC_ENABLE - Boolean (defined / not defined)
+ * BOARD_XOSC_FREQUENCY - In Hz
+ * BOARD_XOSC_STARTUPTIME - See SYSCTRL_XOSC_STARTUP_* definitions
+ * BOARD_XOSC_ISCRYSTAL - Boolean (defined / not defined)
+ * BOARD_XOSC_AMPGC - Boolean (defined / not defined)
+ * BOARD_XOSC_ONDEMAND - Boolean (defined / not defined)
+ * BOARD_XOSC_RUNINSTANDBY - Boolean (defined / not defined)
+ */
+
+#undef BOARD_XOSC_ENABLE
+#define BOARD_XOSC_FREQUENCY 12000000UL
+#define BOARD_XOSC_STARTUPTIME SYSCTRL_XOSC_STARTUP_1S
+#define BOARD_XOSC_ISCRYSTAL 1
+#define BOARD_XOSC_AMPGC 1
+#define BOARD_XOSC_ONDEMAND 1
+#undef BOARD_XOSC_RUNINSTANDBY
+
+/* XOSC32 Configuration -- Not used
+ *
+ * BOARD_XOSC32K_ENABLE - Boolean (defined / not defined)
+ * BOARD_XOSC32K_FREQUENCY - In Hz
+ * BOARD_XOSC32K_STARTUPTIME - See SYSCTRL_XOSC32K_STARTUP_* definitions
+ * BOARD_XOSC32K_ISCRYSTAL - Boolean (defined / not defined)
+ * BOARD_XOSC32K_AAMPEN - Boolean (defined / not defined)
+ * BOARD_XOSC32K_EN1KHZ - Boolean (defined / not defined)
+ * BOARD_XOSC32K_EN32KHZ - Boolean (defined / not defined)
+ * BOARD_XOSC32K_ONDEMAND - Boolean (defined / not defined)
+ * BOARD_XOSC32K_RUNINSTANDBY - Boolean (defined / not defined)
+ */
+
+#undef BOARD_XOSC32K_ENABLE
+#define BOARD_XOSC32K_FREQUENCY 32768 /* 32.768KHz XTAL */
+#define BOARD_XOSC32K_STARTUPTIME SYSCTRL_XOSC32K_STARTUP_2S
+#define BOARD_XOSC32K_ISCRYSTAL 1
+#define BOARD_XOSC32K_AAMPEN 1
+#undef BOARD_XOSC32K_EN1KHZ
+#define BOARD_XOSC32K_EN32KHZ 1
+#define BOARD_XOSC32K_ONDEMAND 1
+#undef BOARD_XOSC32K_RUNINSTANDBY
+
+/* OSC32 Configuration -- not used
+ *
+ * BOARD_OSC32K_ENABLE - Boolean (defined / not defined)
+ * BOARD_OSC32K_FREQUENCY - In Hz
+ * BOARD_OSC32K_STARTUPTIME - See SYSCTRL_OSC32K_STARTUP_* definitions
+ * BOARD_OSC32K_EN1KHZ - Boolean (defined / not defined)
+ * BOARD_OSC32K_EN32KHZ - Boolean (defined / not defined)
+ * BOARD_OSC32K_ONDEMAND - Boolean (defined / not defined)
+ * BOARD_OSC32K_RUNINSTANDBY - Boolean (defined / not defined)
+ */
+
+#undef BOARD_OSC32K_ENABLE
+#define BOARD_OSC32K_FREQUENCY 32768 /* 32.768kHz internal oscillator */
+#define BOARD_OSC32K_STARTUPTIME SYSCTRL_OSC32K_STARTUP_4MS
+#define BOARD_OSC32K_EN1KHZ 1
+#define BOARD_OSC32K_EN32KHZ 1
+#define BOARD_OSC32K_ONDEMAND 1
+#undef BOARD_OSC32K_RUNINSTANDBY
+
+/* OSC8M Configuration -- always enabled
+ *
+ * BOARD_OSC8M_PRESCALER - See SYSCTRL_OSC8M_PRESC_DIV* definitions
+ * BOARD_OSC8M_ONDEMAND - Boolean (defined / not defined)
+ * BOARD_OSC8M_RUNINSTANDBY - Boolean (defined / not defined)
+ */
+
+#define BOARD_OSC8M_PRESCALER SYSCTRL_OSC8M_PRESC_DIV1
+#define BOARD_OSC8M_ONDEMAND 1
+#undef BOARD_OSC8M_RUNINSTANDBY
+
+#define BOARD_OSC8M_FREQUENCY 8000000 /* 8MHz high-accuracy internal oscillator */
+
+/* OSCULP32K Configuration -- not used. */
+
+#define BOARD_OSCULP32K_FREQUENCY 32000 /* 32kHz ultra-low-power internal oscillator */
+
+/* Digital Frequency Locked Loop configuration. In closed-loop mode, the
+ * DFLL output frequency (Fdfll) is given by:
+ *
+ * Fdfll = DFLLmul * Frefclk
+ * = 6 * 8000000 = 48MHz
+ *
+ * Where the reference clock is Generic Clock Channel 0 output of GLCK1.
+ * GCLCK1 provides OSC8M, undivided.
+ *
+ * When operating in open-loop mode, the output frequency of the DFLL will
+ * be determined by the values written to the DFLL Coarse Value bit group
+ * and the DFLL Fine Value bit group in the DFLL Value register.
+ *
+ * BOARD_DFLL_OPENLOOP - Boolean (defined / not defined)
+ * BOARD_DFLL_TRACKAFTERFINELOCK - Boolean (defined / not defined)
+ * BOARD_DFLL_KEEPLOCKONWAKEUP - Boolean (defined / not defined)
+ * BOARD_DFLL_ENABLECHILLCYCLE - Boolean (defined / not defined)
+ * BOARD_DFLL_QUICKLOCK - Boolean (defined / not defined)
+ * BOARD_DFLL_ONDEMAND - Boolean (defined / not defined)
+ *
+ * Closed loop mode only:
+ * BOARD_DFLL_GCLKGEN - GCLK index
+ * BOARD_DFLL_MULTIPLIER - Value
+ * BOARD_DFLL_MAXCOARSESTEP - Value
+ * BOARD_DFLL_MAXFINESTEP - Value
+ *
+ * BOARD_DFLL_FREQUENCY - The resulting frequency
+ */
+
+#define BOARD_DFLL_ENABLE 1
+#define BOARD_DFLL_OPENLOOP 1
+#undef BOARD_DFLL_ONDEMAND
+#undef BOARD_DFLL_RUNINSTANDBY
+
+/* DFLL closed loop mode configuration */
+
+#define BOARD_DFLL_SRCGCLKGEN 1
+#define BOARD_DFLL_MULTIPLIER 6
+#define BOARD_DFLL_QUICKLOCK 1
+#define BOARD_DFLL_TRACKAFTERFINELOCK 1
+#define BOARD_DFLL_KEEPLOCKONWAKEUP 1
+#define BOARD_DFLL_ENABLECHILLCYCLE 1
+#define BOARD_DFLL_MAXCOARSESTEP (0x1f / 4)
+#define BOARD_DFLL_MAXFINESTEP (0xff / 4)
+
+#define BOARD_DFLL_FREQUENCY (48000000)
+
+/* GCLK Configuration
+ *
+ * Global enable/disable.
+ *
+ * BOARD_GCLK_ENABLE - Boolean (defined / not defined)
+ *
+ * For n=1-7:
+ * BOARD_GCLKn_ENABLE - Boolean (defined / not defined)
+ *
+ * For n=0-8:
+ * BOARD_GCLKn_RUN_IN_STANDBY - Boolean (defined / not defined)
+ * BOARD_GCLKn_CLOCK_SOURCE - See GCLK_GENCTRL_SRC_* definitions
+ * BOARD_GCLKn_PRESCALER - Value
+ * BOARD_GCLKn_OUTPUT_ENABLE - Boolean (defined / not defined)
+ */
+
+#define BOARD_GCLK_ENABLE 1
+
+/* GCLK generator 0 (Main Clock) - Source is the DFLL */
+
+#undef BOARD_GCLK0_RUN_IN_STANDBY
+#define BOARD_GCLK0_CLOCK_SOURCE GCLK_GENCTRL_SRC_DFLL48M
+#define BOARD_GCLK0_PRESCALER 1
+#undef BOARD_GCLK0_OUTPUT_ENABLE
+#define BOARD_GCLK0_FREQUENCY (BOARD_DFLL_FREQUENCY / BOARD_GCLK0_PRESCALER)
+
+/* Configure GCLK generator 1 - Drives the DFLL */
+
+#define BOARD_GCLK1_ENABLE 1
+#undef BOARD_GCLK1_RUN_IN_STANDBY
+#define BOARD_GCLK1_CLOCK_SOURCE GCLK_GENCTRL_SRC_OSC8M
+#define BOARD_GCLK1_PRESCALER 1
+#undef BOARD_GCLK1_OUTPUT_ENABLE
+#define BOARD_GCLK1_FREQUENCY (BOARD_OSC8M_FREQUENCY / BOARD_GCLK1_PRESCALER)
+
+/* Configure GCLK generator 2 (RTC) */
+
+#undef BOARD_GCLK2_ENABLE
+#undef BOARD_GCLK2_RUN_IN_STANDBY
+#define BOARD_GCLK2_CLOCK_SOURCE GCLK_GENCTRL_SRC_OSC32K
+#define BOARD_GCLK2_PRESCALER 32
+#undef BOARD_GCLK2_OUTPUT_ENABLE
+#define BOARD_GCLK2_FREQUENCY (BOARD_OSC8M_FREQUENCY / BOARD_GCLK2_PRESCALER)
+
+/* Configure GCLK generator 3 */
+
+#undef BOARD_GCLK3_ENABLE
+#undef BOARD_GCLK3_RUN_IN_STANDBY
+#define BOARD_GCLK3_CLOCK_SOURCE GCLK_GENCTRL_SRC_OSC8M
+#define BOARD_GCLK3_PRESCALER 1
+#undef BOARD_GCLK3_OUTPUT_ENABLE
+#define BOARD_GCLK3_FREQUENCY (BOARD_OSC8M_FREQUENCY / BOARD_GCLK3_PRESCALER)
+
+/* Configure GCLK generator 4 */
+
+#undef BOARD_GCLK4_ENABLE
+#undef BOARD_GCLK4_RUN_IN_STANDBY
+#define BOARD_GCLK4_CLOCK_SOURCE GCLK_GENCTRL_SRC_OSC8M
+#define BOARD_GCLK4_PRESCALER 1
+#undef BOARD_GCLK4_OUTPUT_ENABLE
+#define BOARD_GCLK4_FREQUENCY (BOARD_OSC8M_FREQUENCY / BOARD_GCLK4_PRESCALER)
+
+/* Configure GCLK generator 5 */
+
+#undef BOARD_GCLK5_ENABLE
+#undef BOARD_GCLK5_RUN_IN_STANDBY
+#define BOARD_GCLK5_CLOCK_SOURCE GCLK_GENCTRL_SRC_OSC8M
+#define BOARD_GCLK5_PRESCALER 1
+#undef BOARD_GCLK5_OUTPUT_ENABLE
+#define BOARD_GCLK5_FREQUENCY (BOARD_OSC8M_FREQUENCY / BOARD_GCLK5_PRESCALER)
+
+/* Configure GCLK generator 6 */
+
+#undef BOARD_GCLK6_ENABLE
+#undef BOARD_GCLK6_RUN_IN_STANDBY
+#define BOARD_GCLK6_CLOCK_SOURCE GCLK_GENCTRL_SRC_OSC8M
+#define BOARD_GCLK6_PRESCALER 1
+#undef BOARD_GCLK6_OUTPUT_ENABLE
+#define BOARD_GCLK6_FREQUENCY (BOARD_OSC8M_FREQUENCY / BOARD_GCLK6_PRESCALER)
+
+/* Configure GCLK generator 7 */
+
+#undef BOARD_GCLK7_ENABLE
+#undef BOARD_GCLK7_RUN_IN_STANDBY
+#define BOARD_GCLK7_CLOCK_SOURCE GCLK_GENCTRL_SRC_OSC8M
+#define BOARD_GCLK7_PRESCALER 1
+#undef BOARD_GCLK7_OUTPUT_ENABLE
+#define BOARD_GCLK7_FREQUENCY (BOARD_OSC8M_FREQUENCY / BOARD_GCLK7_PRESCALER)
+
+/* The source of the main clock is always GCLK_MAIN. Also called GCLKGEN[0],
+ * this is the clock feeding the Power Manager.
+ * The Power Manager, in turn, generates main clock which is divided down to
+ * produce the CPU, AHB, and APB clocks.
+ *
+ * The main clock is initially OSC8M divided by 8.
+ */
+
+#define BOARD_GCLK_MAIN_FREQUENCY BOARD_GCLK0_FREQUENCY
+
+/* Main clock dividers
+ *
+ * BOARD_CPU_DIVIDER - See PM_CPUSEL_CPUDIV_* definitions
+ * BOARD_CPU_FREQUENCY - In Hz
+ * BOARD_CPU_FAILDECT - Boolean (defined / not defined)
+ * BOARD_APBA_DIVIDER - See M_APBASEL_APBADIV_* definitions
+ * BOARD_APBA_FREQUENCY - In Hz
+ * BOARD_APBB_DIVIDER - See M_APBBSEL_APBBDIV_* definitions
+ * BOARD_APBB_FREQUENCY - In Hz
+ * BOARD_APBC_DIVIDER - See M_APBCSEL_APBCDIV_* definitions
+ * BOARD_APBC_FREQUENCY - In Hz
+ */
+
+#define BOARD_CPU_FAILDECT 1
+#define BOARD_CPU_DIVIDER PM_CPUSEL_CPUDIV_1
+#define BOARD_APBA_DIVIDER PM_APBASEL_APBADIV_1
+#define BOARD_APBB_DIVIDER PM_APBBSEL_APBBDIV_1
+#define BOARD_APBC_DIVIDER PM_APBCSEL_APBCDIV_1
+
+/* Resulting frequencies */
+
+#define BOARD_MCK_FREQUENCY (BOARD_GCLK_MAIN_FREQUENCY)
+#define BOARD_CPU_FREQUENCY (BOARD_MCK_FREQUENCY)
+#define BOARD_PBA_FREQUENCY (BOARD_MCK_FREQUENCY)
+#define BOARD_PBB_FREQUENCY (BOARD_MCK_FREQUENCY)
+#define BOARD_PBC_FREQUENCY (BOARD_MCK_FREQUENCY)
+#define BOARD_PBD_FREQUENCY (BOARD_MCK_FREQUENCY)
+
+/* FLASH wait states
+ *
+ * Vdd Range Wait states Maximum Operating Frequency
+ * ------------- -------------- ---------------------------
+ * 1.62V to 2.7V 0 14 MHz
+ * 1 28 MHz
+ * 2 42 MHz
+ * 3 48 MHz
+ * 2.7V to 3.63V 0 24 MHz
+ * 1 48 MHz
+ */
+
+#if 0 /* REVISIT -- should not be necessary */
+# define BOARD_FLASH_WAITSTATES 1
+#else
+# define BOARD_FLASH_WAITSTATES 2
+#endif
+
+/* SERCOM definitions *******************************************************/
+
+/* This is the source clock generator for the GCLK_SERCOM_SLOW clock that is
+ * common to all SERCOM modules.
+ */
+
+#define BOARD_SERCOM05_SLOW_GCLKGEN 0
+
+/* The SERCOM4 USART is available on the pins below.
+ *
+ * PIN EXT1 GPIO Function
+ * ---- ---- ------------------
+ * 13 PB09 SERCOM4 / USART RX
+ * 14 PB08 SERCOM4 / USART TX
+ * 19 GND N/A
+ * 20 VCC N/A
+ *
+ * If you have a TTL to RS-232 converter then this is the most convenient
+ * serial console to use (because you don't lose the console device each time
+ * you lose the USB connection). It is the default in all of the SAMD21
+ * configurations.
+ */
+
+#define BOARD_SERCOM4_GCLKGEN 0
+#define BOARD_SERCOM4_SLOW_GCLKGEN BOARD_SERCOM05_SLOW_GCLKGEN
+
+#if defined(CONFIG_USART4_SERIAL_CONSOLE)
+# define BOARD_SERCOM4_MUXCONFIG (USART_CTRLA_RXPAD1 | USART_CTRLA_TXPAD0_1)
+# define BOARD_SERCOM4_PINMAP_PAD0 PORT_SERCOM4_PAD0_3 /* USART TX */
+# define BOARD_SERCOM4_PINMAP_PAD1 PORT_SERCOM4_PAD1_3 /* USART RX */
+# define BOARD_SERCOM4_PINMAP_PAD2 0
+# define BOARD_SERCOM4_PINMAP_PAD3 0
+#endif /* CONFIG_USART4_SERIAL_CONSOLE */
+
+#define BOARD_SERCOM4_FREQUENCY BOARD_GCLK0_FREQUENCY
+
+/* USB definitions **********************************************************/
+
+/* This is the source clock generator for the GCLK_USB clock
+ */
+
+#define BOARD_USB_GCLKGEN 0
+#define BOARD_USB_FREQUENCY BOARD_GCLK0_FREQUENCY
+
+/* default USB Pad calibration (not used yet by USB driver) */
+
+#define BOARD_USB_PADCAL_P 29
+#define BOARD_USB_PADCAL_N 5
+#define BOARD_USB_PADCAL_TRIM 3
+
+/* LED definitions **********************************************************/
+
+/* LED index values for use with board_userled() */
+
+#define BOARD_STATUS_LED 0
+#define BOARD_NLEDS 1
+
+/* LED bits for use with board_userled_all() */
+
+#define BOARD_STATUS LED_BIT (1 << BOARD_STATUS_LED)
+
+/* When CONFIG_ARCH_LEDS is defined in the NuttX configuration, NuttX will
+ * control the LED as defined below. Thus if the LED is statically on, NuttX
+ * has successfully booted and is, apparently, running normally.
+ * If the LED is flashing at approximately 2Hz, then a fatal error
+ * has been detected and the system has halted.
+ */
+
+#define LED_STARTED 0 /* STATUS LED=OFF */
+#define LED_HEAPALLOCATE 0 /* STATUS LED=OFF */
+#define LED_IRQSENABLED 0 /* STATUS LED=OFF */
+#define LED_STACKCREATED 1 /* STATUS LED=ON */
+#define LED_INIRQ 2 /* STATUS LED=no change */
+#define LED_SIGNAL 2 /* STATUS LED=no change */
+#define LED_ASSERTION 2 /* STATUS LED=no change */
+#define LED_PANIC 3 /* STATUS LED=flashing */
+
+#endif /* __BOARDS_ARM_SAMD2L2_XIAO_SEEEDUINO_INCLUDE_BOARD_H */
diff --git a/boards/arm/samd2l2/xiao-seeeduino/scripts/Make.defs b/boards/arm/samd2l2/xiao-seeeduino/scripts/Make.defs
new file mode 100644
index 0000000000000..a90a9c5d1ba20
--- /dev/null
+++ b/boards/arm/samd2l2/xiao-seeeduino/scripts/Make.defs
@@ -0,0 +1,39 @@
+############################################################################
+# boards/arm/samd2l2/xiao-seeeduino/scripts/Make.defs
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership. The
+# ASF licenses this file to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance with the
+# License. You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+############################################################################
+
+include $(TOPDIR)/.config
+include $(TOPDIR)/tools/Config.mk
+include $(TOPDIR)/arch/arm/src/armv6-m/Toolchain.defs
+
+LDSCRIPT = flash.ld
+ARCHSCRIPT += $(BOARD_DIR)$(DELIM)scripts$(DELIM)$(LDSCRIPT)
+
+ARCHPICFLAGS = -fpic -msingle-pic-base -mpic-register=r10
+
+CFLAGS := $(ARCHCFLAGS) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRAFLAGS)
+CPICFLAGS = $(ARCHPICFLAGS) $(CFLAGS)
+CXXFLAGS := $(ARCHCXXFLAGS) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHXXINCLUDES) $(ARCHDEFINES) $(EXTRAFLAGS)
+CXXPICFLAGS = $(ARCHPICFLAGS) $(CXXFLAGS)
+CPPFLAGS := $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRAFLAGS)
+AFLAGS := $(CFLAGS) -D__ASSEMBLY__
+
+NXFLATLDFLAGS1 = -r -d -warn-common
+NXFLATLDFLAGS2 = $(NXFLATLDFLAGS1) -T$(TOPDIR)/binfmt/libnxflat/gnu-nxflat-pcrel.ld -no-check-sections
+LDNXFLATFLAGS = -e main -s 2048
diff --git a/boards/arm/samd2l2/xiao-seeeduino/scripts/flash.ld b/boards/arm/samd2l2/xiao-seeeduino/scripts/flash.ld
new file mode 100644
index 0000000000000..d276d4098df45
--- /dev/null
+++ b/boards/arm/samd2l2/xiao-seeeduino/scripts/flash.ld
@@ -0,0 +1,112 @@
+/****************************************************************************
+ * boards/arm/samd2l2/xiao-seeeduino/scripts/flash.ld
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/* The ATSAMD21J18A has 256KB of FLASH beginning at address 0x0000:0000 and
+ * 32KB of SRAM beginning at address 0x2000:0000
+ * However, the XIAO Seeeduino has its UF2 bootloader in the first 8KB.
+ */
+
+MEMORY
+{
+ flash (rx) : ORIGIN = 0x00002000, LENGTH = 248K
+ sram (rwx) : ORIGIN = 0x20000000, LENGTH = 32K
+}
+
+OUTPUT_ARCH(arm)
+EXTERN(_vectors)
+ENTRY(_stext)
+
+SECTIONS
+{
+ .text : {
+ _stext = ABSOLUTE(.);
+ *(.vectors)
+ *(.text .text.*)
+ *(.fixup)
+ *(.gnu.warning)
+ *(.rodata .rodata.*)
+ *(.gnu.linkonce.t.*)
+ *(.glue_7)
+ *(.glue_7t)
+ *(.got)
+ *(.gcc_except_table)
+ *(.gnu.linkonce.r.*)
+ _etext = ABSOLUTE(.);
+ } > flash
+
+ .init_section : {
+ _sinit = ABSOLUTE(.);
+ KEEP(*(SORT_BY_INIT_PRIORITY(.init_array.*) SORT_BY_INIT_PRIORITY(.ctors.*)))
+ KEEP(*(.init_array EXCLUDE_FILE(*crtbegin.o *crtbegin?.o *crtend.o *crtend?.o) .ctors))
+ _einit = ABSOLUTE(.);
+ } > flash
+
+ .ARM.extab : {
+ *(.ARM.extab*)
+ } >flash
+
+ .ARM.exidx : {
+ __exidx_start = ABSOLUTE(.);
+ *(.ARM.exidx*)
+ __exidx_end = ABSOLUTE(.);
+ } >flash
+
+ .data : {
+ _sdata = ABSOLUTE(.);
+ *(.data .data.*)
+ *(.gnu.linkonce.d.*)
+ CONSTRUCTORS
+ . = ALIGN(4);
+ _edata = ABSOLUTE(.);
+ } > sram AT > flash
+
+ _eronly = LOADADDR(.data);
+
+ .ramfunc ALIGN(4): {
+ _sramfuncs = ABSOLUTE(.);
+ *(.ramfunc .ramfunc.*)
+ _eramfuncs = ABSOLUTE(.);
+ } > sram AT > flash
+
+ _framfuncs = LOADADDR(.ramfunc);
+
+ .bss : {
+ _sbss = ABSOLUTE(.);
+ *(.bss .bss.*)
+ *(.gnu.linkonce.b.*)
+ *(COMMON)
+ . = ALIGN(4);
+ _ebss = ABSOLUTE(.);
+ } > sram
+
+ /* Stabs debugging sections. */
+ .stab 0 : { *(.stab) }
+ .stabstr 0 : { *(.stabstr) }
+ .stab.excl 0 : { *(.stab.excl) }
+ .stab.exclstr 0 : { *(.stab.exclstr) }
+ .stab.index 0 : { *(.stab.index) }
+ .stab.indexstr 0 : { *(.stab.indexstr) }
+ .comment 0 : { *(.comment) }
+ .debug_abbrev 0 : { *(.debug_abbrev) }
+ .debug_info 0 : { *(.debug_info) }
+ .debug_line 0 : { *(.debug_line) }
+ .debug_pubnames 0 : { *(.debug_pubnames) }
+ .debug_aranges 0 : { *(.debug_aranges) }
+}
diff --git a/boards/arm/samd2l2/xiao-seeeduino/src/Makefile b/boards/arm/samd2l2/xiao-seeeduino/src/Makefile
new file mode 100644
index 0000000000000..cab39390b0362
--- /dev/null
+++ b/boards/arm/samd2l2/xiao-seeeduino/src/Makefile
@@ -0,0 +1,33 @@
+############################################################################
+# boards/arm/samd2l2/xiao-seeeduino/src/Makefile
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership. The
+# ASF licenses this file to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance with the
+# License. You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+############################################################################
+
+include $(TOPDIR)/Make.defs
+
+CSRCS = sam_boot.c
+
+ifeq ($(CONFIG_ARCH_LEDS),y)
+CSRCS += sam_autoleds.c
+endif
+
+ifeq ($(CONFIG_BOARDCTL),y)
+CSRCS += sam_appinit.c
+endif
+
+include $(TOPDIR)/boards/Board.mk
diff --git a/boards/arm/samd2l2/xiao-seeeduino/src/sam_appinit.c b/boards/arm/samd2l2/xiao-seeeduino/src/sam_appinit.c
new file mode 100644
index 0000000000000..f951d6497c5e4
--- /dev/null
+++ b/boards/arm/samd2l2/xiao-seeeduino/src/sam_appinit.c
@@ -0,0 +1,71 @@
+/****************************************************************************
+ * boards/arm/samd2l2/xiao-seeeduino/src/sam_appinit.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include
+
+#include
+#include
+
+#include
+
+#include "sam_config.h"
+#include "xiao-seeeduino.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: board_app_initialize
+ *
+ * Description:
+ * Perform application specific initialization. This function is never
+ * called directly from application code, but only indirectly via the
+ * (non-standard) boardctl() interface using the command BOARDIOC_INIT.
+ *
+ * Input Parameters:
+ * arg - The boardctl() argument is passed to the board_app_initialize()
+ * implementation without modification. The argument has no
+ * meaning to NuttX; the meaning of the argument is a contract
+ * between the board-specific initialization logic and the
+ * matching application logic. The value could be such things as a
+ * mode enumeration value, a set of DIP switch switch settings, a
+ * pointer to configuration data read from a file or serial FLASH,
+ * or whatever you would like to do with it. Every implementation
+ * should accept zero/NULL as a default configuration.
+ *
+ * Returned Value:
+ * Zero (OK) is returned on success; a negated errno value is returned on
+ * any failure to indicate the nature of the failure.
+ *
+ ****************************************************************************/
+
+int board_app_initialize(uintptr_t arg)
+{
+ return OK;
+}
diff --git a/boards/arm/samd2l2/xiao-seeeduino/src/sam_autoleds.c b/boards/arm/samd2l2/xiao-seeeduino/src/sam_autoleds.c
new file mode 100644
index 0000000000000..57c724e7acdb7
--- /dev/null
+++ b/boards/arm/samd2l2/xiao-seeeduino/src/sam_autoleds.c
@@ -0,0 +1,142 @@
+/****************************************************************************
+ * boards/arm/samd2l2/xiao-seeeduino/src/sam_autoleds.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/* When CONFIG_ARCH_LEDS is defined in the NuttX configuration, NuttX will
+ * control the LED as follows:
+ *
+ * SYMBOL Meaning LED
+ * ------------------- ----------------------- ------
+ * LED_STARTED NuttX has been started OFF
+ * LED_HEAPALLOCATE Heap has been allocated OFF
+ * LED_IRQSENABLED Interrupts enabled OFF
+ * LED_STACKCREATED Idle stack created ON
+ * LED_INIRQ In an interrupt** N/C
+ * LED_SIGNAL In a signal handler*** N/C
+ * LED_ASSERTION An assertion failed N/C
+ * LED_PANIC The system has crashed FLASH
+ *
+ * Thus if the LED is statically on, NuttX has successfully booted and is,
+ * apparently, running normally. If the LED is flashing at approximately
+ * 2Hz, then a fatal error has been detected and the system has halted.
+ */
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include
+
+#include
+#include
+#include
+#include
+
+#include
+#include
+
+#include "sam_port.h"
+#include "xiao-seeeduino.h"
+
+#ifdef CONFIG_ARCH_LEDS
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: board_autoled_initialize
+ ****************************************************************************/
+
+void board_autoled_initialize(void)
+{
+ sam_configport(PORT_STATUS_LED);
+}
+
+/****************************************************************************
+ * Name: board_autoled_on
+ ****************************************************************************/
+
+void board_autoled_on(int led)
+{
+ bool ledstate = true;
+
+ switch (led)
+ {
+ case 0: /* LED_STARTED: NuttX has been started STATUS LED=OFF
+ * LED_HEAPALLOCATE: Heap has been allocated STATUS LED=OFF
+ * LED_IRQSENABLED: Interrupts enabled STATUS LED=OFF
+ */
+
+ break; /* Leave ledstate == true to turn OFF */
+
+ default:
+ case 2: /* LED_INIRQ: In an interrupt STATUS LED=N/C
+ * LED_SIGNAL: In a signal handler STATUS LED=N/C
+ * LED_ASSERTION: An assertion failed STATUS LED=N/C
+ */
+
+ return; /* Return to leave STATUS LED unchanged */
+
+ case 3: /* LED_PANIC: The system has crashed STATUS LED=FLASH */
+ case 1: /* LED_STACKCREATED: Idle stack created STATUS LED=ON */
+
+ ledstate = false; /* Set ledstate == false to turn ON */
+ break;
+ }
+
+ sam_portwrite(PORT_STATUS_LED, ledstate);
+}
+
+/****************************************************************************
+ * Name: board_autoled_off
+ ****************************************************************************/
+
+void board_autoled_off(int led)
+{
+ switch (led)
+ {
+ /* These should not happen and are ignored */
+
+ default:
+ case 0: /* LED_STARTED: NuttX has been started STATUS LED=OFF
+ * LED_HEAPALLOCATE: Heap has been allocated STATUS LED=OFF
+ * LED_IRQSENABLED: Interrupts enabled STATUS LED=OFF
+ */
+
+ case 1: /* LED_STACKCREATED: Idle stack created STATUS LED=ON */
+
+ /* These result in no-change */
+
+ case 2: /* LED_INIRQ: In an interrupt STATUS LED=N/C
+ * LED_SIGNAL: In a signal handler STATUS LED=N/C
+ * LED_ASSERTION: An assertion failed STATUS LED=N/C
+ */
+
+ return; /* Return to leave STATUS LED unchanged */
+
+ /* Turn STATUS LED off set driving the output high */
+
+ case 3: /* LED_PANIC: The system has crashed STATUS LED=FLASH */
+ sam_portwrite(PORT_STATUS_LED, true);
+ break;
+ }
+}
+
+#endif /* CONFIG_ARCH_LEDS */
diff --git a/boards/arm/samd2l2/xiao-seeeduino/src/sam_boot.c b/boards/arm/samd2l2/xiao-seeeduino/src/sam_boot.c
new file mode 100644
index 0000000000000..8f7f041242156
--- /dev/null
+++ b/boards/arm/samd2l2/xiao-seeeduino/src/sam_boot.c
@@ -0,0 +1,64 @@
+/****************************************************************************
+ * boards/arm/samd2l2/xiao-seeeduino/src/sam_boot.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include
+
+#include
+
+#include
+
+#include "sam_config.h"
+#include "xiao-seeeduino.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: sam_boardinitialize
+ *
+ * Description:
+ * All SAM3U architectures must provide the following entry point.
+ * This entry point is called early in the initialization -- after all
+ * memory has been configured and mapped but before any devices have been
+ * initialized.
+ *
+ ****************************************************************************/
+
+void sam_boardinitialize(void)
+{
+ /* Configure on-board LEDs if LED support has been selected. */
+
+#ifdef CONFIG_ARCH_LEDS
+ board_autoled_initialize();
+#endif
+}
diff --git a/boards/arm/samd2l2/xiao-seeeduino/src/xiao-seeeduino.h b/boards/arm/samd2l2/xiao-seeeduino/src/xiao-seeeduino.h
new file mode 100644
index 0000000000000..d15dce7480e7c
--- /dev/null
+++ b/boards/arm/samd2l2/xiao-seeeduino/src/xiao-seeeduino.h
@@ -0,0 +1,89 @@
+/****************************************************************************
+ * boards/arm/samd2l2/xiao-seeeduino/src/xiao-seeeduino.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __BOARDS_ARM_SAMD2L2_XIAO_SEEEDUINO_SRC_XIAO_SEEEDUINO_H
+#define __BOARDS_ARM_SAMD2L2_XIAO_SEEEDUINO_SRC_XIAO_SEEEDUINO_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include
+#include
+
+#include
+
+#include
+#include
+
+#include "sam_config.h"
+#include "sam_pinmap.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* LEDs:
+ * There are three LEDs on board the SAMD21 Xplained Pro board: The EDBG
+ * controls two of the LEDs, a power LED and a status LED. There is only
+ * one user controllable LED, a yellow LED labelled STATIS near the SAMD21
+ * USB connector.
+ *
+ * This LED is controlled by PB30 and the LED can be activated by driving
+ * PB30 to GND.
+ *
+ * When CONFIG_ARCH_LEDS is defined in the NuttX configuration, NuttX will
+ * control the LED as follows:
+ *
+ * SYMBOL Meaning LED
+ * ------------------- ----------------------- ------
+ * LED_STARTED NuttX has been started OFF
+ * LED_HEAPALLOCATE Heap has been allocated OFF
+ * LED_IRQSENABLED Interrupts enabled OFF
+ * LED_STACKCREATED Idle stack created ON
+ * LED_INIRQ In an interrupt N/C
+ * LED_SIGNAL In a signal handler N/C
+ * LED_ASSERTION An assertion failed N/C
+ * LED_PANIC The system has crashed FLASH
+ *
+ * Thus if the LED is statically on, NuttX has successfully booted and is,
+ * apparently, running normally. If the LED is flashing at approximately
+ * 2Hz, then a fatal error has been detected and the system has halted.
+ */
+
+#define PORT_STATUS_LED (PORT_OUTPUT | PORT_PULL_NONE | PORT_OUTPUT_SET | \
+ PORTA | PORT_PIN4)
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+#ifndef __ASSEMBLY__
+
+/****************************************************************************
+ * Public Functions Definitions
+ ****************************************************************************/
+
+#endif /* __ASSEMBLY__ */
+#endif /* __BOARDS_ARM_SAMD2L2_XIAO_SEEEDUINO_SRC_XIAO_SEEEDUINO_H */