CPU: Atmel ATSAMD21G18

CPU Speed: 48 MHz

Operating Voltage: 3.3 V

Analog In/Out: 6/1

Digital I/O: 20

Flash Memory: 256 KB



Danyboard M0 is an open-source electronics prototyping platform. Danyboard M0 is designed to provide an efficient, fast, simple and cost effective solution to create IoT and wearable devices. But the board can also drive a robotic arm, located in the other side of the world, using internet…

It is equipped with:

  • MCU Atmel SAMD21 32bit ARM Cortex M0+
  • Wi-Fi 2.4GHz
  • MicroSD Reader
  • RTC
  • Li-Po charger

The board includes a Li-Po charging circuit that allows the danyboard M0 to run on battery power or external 5V, charging the Li-Po battery while running on external power. Switching from one source to the other is done automatically.

Warning: The Danyboard M0 runs at 3.3V. The maximum voltage that the I/O pins can tolerate is 3.3V. Applying voltages higher than 3.3V to any I/O pin could damage the board. While output to 5V digital devices is possible, bidirectional communication with 5V devices needs proper level shifting.

Getting Started

You can find in the Getting Started section all the information you need to configure your board, use the Arduino Software (IDE), and start tinker with coding and electronics. Full details and examples on how to use the WiFi interface are available in the EspWiFi Library reference page.

Technical specs

Microcontroller ATSAMD21G18A, 32-bit ARM Cortex M0+
Voltage 3.3 V
Board Power Supply 3.3 – 5 V (USB, VIN)
Flash Memory 256 KB
Digital I/O Pins 20, with 10 PWM
Analog Input Pins 6, 12-bit ADC channels
 Analog Output Pin 1, 10-bit DAC channel
External Interrupts All pins except pins 2 and 4
DC Current per I/O Pin 7 mA
I2C 1
I2S 1
Clock Speed 48 MHz
RTC 32.768 KHz
Supported Battery Li-Po Single Cell 3.7 V
Wi-Fi IEEE 802.11 b/g/n 2.4 GHz
MicroSD Reader
Dimensions 26×63 mm
Full-Speed USB Device and embedded Host


The Danyboard M0 is open-source hardware! You can build your own board using the following files:

ARM Core Benefits

The Danyboard M0 has a 32-bit ARM core that can outperform typical 8-bit microcontroller boards. The most significant differences are:

  • 32-bit core that allows operations on 4 byte wide data within a single CPU clock.
  • CPU Clock at 48MHz
  • 12 channels DMA controller that can relieve the CPU from doing memory intensive tasks
  • 32 bit Real Time Counter (RTC) with clock/calendar function
  • 32 bit CRC generator
  • Two-channel Inter IC Sound (I2S) interface
  • Peripheral Touch Controller (PTC)

For further information about the SAM-D21 microcontroller please refer to the datasheet.

Li-Po batteries, Pins and board LEDs


Battery capacity

Li-Po batteries are charged up to 4,2V with a current that is usually half of the nominal capacity (C/2). For Danyboard M0 we use a specialized chip that has a preset charging current of 256 mAh. This means that the MINIMUM capacity of the Li-Po battery should be 500 mAh. Smaller cells will be damaged by this current and may overheat, develop internal gasses and explode, setting on fire the surroundings. We strongly recommend that you select a Li-Po battery of at least 500 mAh capacity. A bigger cell will take more time to charge, but won’t be harmed or overheated.


Battery connector

If you want to connect a battery to your M0 board be sure to search one with female 2 pin JST PHR2 Type connector.
Polarity : looking at the board connector pins, polarity is Left = Positive, Right = GND

Download here the Connector datasheet. On the M0 board, connector is a Male 2pin JST PH Type.

Note : DO NOT CONNECT to the male JST connector present on the board anything else than a Li-Po battery whose characteristics are compliant with those indicated above. Please DO NOT POWER VIN with more than 5V.


Vin Pin

This pin can be used to power the board with a regulated 5V source. If the power is fed through this pin, the USB power source is disconnected. This is the only way you can supply 5v (range is 5V to maximum 6V) to the board not using USB.

This pin outputs 5V from the the board when powered from the USB connector or from the Battery pin. It is unregulated and the voltage is taken directly from the inputs. When powered from battery it supplies around 3.7 V.


VBatt Pin

This pin outputs the Battery Voltage.


3.3V Pin

This pin outputs 3.3V through the on-board voltage regulator. This voltage is the same regardless the power source used (USB, Vin and Battery).


Charge LED

The CHARGE LED on the board is driven by the charger chip that monitors the current drawn by the Li-Po battery while charging. Usually it will lit up when the board gets 5V from VIN or USB and the chip starts charging the Li-Po battery connected to the JST connector.
There are several occasions where this LED will start to blink at a frequency of about 2Hz. This flashing is caused by the following conditions maintained for a long time (from 20 to 70 minutes):

  • No battery is connected to JST connector.
  •  Overdischarged/damaged battery is connected. It can’t be recharged.
  • A fully charged battery is put through another unnecessary charging cycle. This is done disconnecting and reconnecting either VIN or the battery itself while VIN is connected.


Onboard LED

On Danyboard M0 the onboard LED is connected to D13.

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