Support for the WeMos Arduino Zero Clone board.

Overview

The WeMos Zero is a cheap clone of Arduino Zero featuring a ATSAMD21G18A. These boards either have a silkscreen "WeMos" or "HW-910" label on their back. Unlike the original Zero, it does not include an embedded debugger/programmer. Instead, the UF2 Bootloader is used to program this board. The SAMD21 is a ARM Cortex-M0+ micro-controller. It has 256KiB of flash memory and 32KiB of RAM.

Note: The official Arduino Zero using the native USB port and the Adafruit Metro M0 Express should also work with this board definition.

Hardware

wemos-zero

MCU

MCU	ATSAMD21G18A
Family	ARM Cortex-M0+
Vendor	Atmel
RAM	32KiB
Flash	256KiB
Frequency	up to 48MHz
FPU	no
Timers	6 (1x 16-bit, 2x 24-bit, 3x 32-bit)
ADCs	6x 12-bit channels)
UARTs	2
SPIs	max 6 (see UART)
I2Cs	max 6 (see UART)
Vcc	1.8V - 3.6V
Datasheet	Datasheet

User Interface

1 LED:

Device	PIN
LED0	PA17

Flashing the device

Assuming the Arduino Bootloader is installed, just run:

make BOARD=wemos-zero flash

Hint: You can you press the reset button twice to manually enter the bootloader. This is helpful if the board has crashed (e.g. due to a failed assert() during start up).