Arduino MKR WAN 1310 Pinout: GPIO, ADC, DAC, PWM, UART, SPI, I2C and LoRa

The Arduino MKR WAN 1310 is a compact LoRa and LoRaWAN board based on the SAMD21 Cortex-M0+ processor.

Its architecture combines:

The board is aimed at low-power remote nodes that need to send relatively small amounts of data over very long distances.

Quick MKR WAN 1310 Specifications

Feature	MKR WAN 1310
Main MCU	SAMD21G18A Cortex-M0+
Clock	48 MHz
Logic voltage	3.3 V
Internal Flash	256 KB
SRAM	32 KB
External Flash	2 MB W25Q16 SPI Flash
Analog inputs	7, A0-A6
ADC	8/10/12-bit Arduino modes; SAMD21 ADC hardware up to 12-bit native
DAC	1 × 10-bit DAC on A0
PWM	13 documented PWM-capable pins
UART	1 external hardware UART
SPI	1 external SPI bus
I2C	1 external I2C bus
USB	Full-Speed USB device / embedded-host capable
LoRa module	Murata CMWX1ZZABZ
LoRa radio	Semtech SX1276
Radio bands	433 / 868 / 915 MHz depending region/configuration
Secure element	ATECC508
Battery	Rechargeable Li-Ion/Li-Po, 3.7 V
GPIO current	7 mA maximum per pin
Size	67.64 × 25 mm

3.3 V Logic Only

The most important electrical rule is:

Arduino explicitly states that the board:

and warns that directly applying 5 V signals can damage it.

This matters when connecting older:

• 5 V sensors;
• UNO-style modules;
• RS-232 adapters;
• 5 V I2C breakouts;
• legacy SPI devices.

The 5 V Pin Does Not Mean 5 V Logic

The board exposes a 5 V/VUSB-related power connection, but that does not change the SAMD21 I/O voltage.

Always treat signal pins as:

GPIO Current Limit

The official full pinout specifies:

with additional source/sink limits for pin groups.

Use a transistor, MOSFET or driver IC for:

• relays;
• motors;
• solenoids;
• high-current LEDs;
• buzzers requiring significant current.

Main Digital Pin Mapping

The main edge exposes:

with the familiar MKR/SAMD21 mapping:

Arduino pin	SAMD21 pin	Main functions
D0	PA22	GPIO / PWM
D1	PA23	GPIO / PWM
D2	PA10	GPIO / PWM
D3	PA11	GPIO / PWM
D4	PB10	GPIO / PWM
D5	PB11	GPIO / PWM
D6	PA20	GPIO / PWM / LED_BUILTIN
D7	PA21	GPIO / PWM
D8	PA16	GPIO / PWM / SPI COPI
D9	PA17	GPIO / SPI SCK
D10	PA19	GPIO / CIPO
D11	PA08	GPIO / I2C SDA
D12	PA09	GPIO / PWM / I2C SCL
D13	PB23	GPIO / UART RX
D14	PB22	GPIO / UART TX

Analog Inputs A0-A6

The board exposes seven analogue inputs:

These also have digital aliases:

Analog pin	Digital alias	SAMD21 pin	Main function
A0	D15	PA02	ADC / DAC0
A1	D16	PB02	ADC
A2	D17	PB03	ADC
A3	D18	PA04	ADC / PWM
A4	D19	PA05	ADC / PWM
A5	D20	PA06	ADC
A6	D21	PA07	ADC

ADC Resolution

Arduino lists analogue input modes of:

and the SAMD21 hardware ADC is a 12-bit converter.

For 12-bit reads:

Then a normal:

returns approximately:

A0 Is a True DAC Output

A0 is connected to:

and provides a genuine:

rather than PWM.

DAC Example

This is useful for:

• control voltages;
• waveform generation;
• slow analogue references;
• audio experiments.

PWM Pins

Arduino currently lists 13 PWM-capable pins:

D9, D11, D13 and D14 are not listed among the default PWM pins.

Hardware UART

The external hardware UART is:

Use:

USB Serial vs Hardware UART

Because SAMD21 has native USB:

This lets the board talk to a PC while simultaneously communicating with a GPS, sensor or another MCU over the hardware UART.

I2C Pins

The main I2C bus is:

Use:

SPI Pins

The user-facing SPI bus is:

Use:

LoRa Hardware Is Separate from Your External SPI Bus

The Murata CMWX1ZZABZ radio is connected internally to the SAMD21 through dedicated control, SPI and I2C signals.

The current Arduino datasheet documents internal radio connections including:

plus shared internal control signals.

These internal connections are not the same as the normal external D8/D9/D10 SPI header.

Murata CMWX1ZZABZ LoRa Module

The wireless module contains:

The STM32L0 runs Arduino-provided radio firmware while the SX1276 handles the LoRa physical layer.

Supported LoRa Frequency Regions

Arduino lists carrier-frequency support around:

depending on regional regulations and network configuration.

Always select the correct frequency plan for the country where the device will operate.

LoRa vs LoRaWAN

The board can be used for:

or:

LoRa describes the radio modulation, while LoRaWAN adds the network protocol and device-management layer.

Arduino LoRa Libraries

Depending on the application, common Arduino software paths include:

• MKRWAN;
• LoRa/point-to-point libraries;
• Arduino Cloud integrations;
• The Things Network workflows.

The Things Network

Arduino explicitly supports using the MKR WAN 1310 with public LoRaWAN infrastructure such as:

where a gateway forwards radio packets to a network server.

Antenna Connection

LoRa communication requires an appropriate antenna matched to the intended band.

Arduino sells/bundles the board for use with an external antenna and lists operation in the regional LoRa bands.

Do not assume a random Wi-Fi/Bluetooth antenna is suitable for:

2 MB External Flash

The MKR WAN 1310 includes a:

This is separate from the SAMD21’s:

What the External Flash Is For

The extra storage is useful for:

• offline sensor logging;
• configuration files;
• queueing measurements while the network is unavailable;
• staging OTA/configuration data;
• temporary local data storage.

External Flash Is Not Extra SRAM

Do not confuse:

with:

The main SAMD21 still has only:

for live variables, stacks and buffers.

ATECC508 Secure Element

The board includes an:

crypto co-processor used for:

• secure key storage;
• device identity;
• certificates;
• cryptographic operations.

This is especially useful for connected IoT devices where private credentials should not be stored as plain Flash data.

Native USB

The SAMD21 provides:

with device and embedded-host capability.

The board can therefore support:

• USB CDC serial;
• USB HID;
• other supported native USB classes.

USB Host Mode Has a Hardware Requirement

Arduino’s current datasheet notes that host mode is available only when:

So do not assume USB host works automatically from every board-power configuration.

Li-Po Battery Support

The board includes charging support for a:

Arduino’s current store specification recommends at least:

capacity.

Why Battery Capacity Matters

The charger has a relatively high minimum charging current compared with tiny wearable batteries.

Do not attach a very small Li-Po without verifying that the battery’s permitted charge current is compatible with the onboard charger.

Low-Power Improvements over MKR WAN 1300

The WAN 1310 revised the power architecture compared with the older WAN 1300.

Arduino specifically highlights:

• new battery charger;
• improved power control;
• 2 MB external Flash;
• much lower properly configured standby consumption.

Arduino quotes figures as low as roughly:

under suitable low-power configuration.

Power Sources

The board can be powered through:

• USB;
• VIN/VUSB header power;
• Li-Po battery.

The board power architecture is designed around approximately:

Do Not Treat MKR VIN Like UNO VIN

Classic UNO users should not assume:

is appropriate simply because an UNO accepts it.

MKR boards use a different power architecture.

LED_BUILTIN

The user LED is:

which matches other MKR-family boards.

External Interrupts

Arduino’s current product specification lists interrupt-capable pins including:

Use:

rather than hard-coding SAMD interrupt channel numbers.

SWD Debugging

The board provides SWD debug/programming pads for advanced development.

Typical signals are:

Common Mistake 1: Applying 5 V to GPIO

The MKR WAN 1310 is explicitly:

Use level shifting where necessary.

Common Mistake 2: Using the Wrong LoRa Frequency Plan

LoRa operation is region-regulated.

A configuration intended for:

is not automatically appropriate in a region using:

plans.

Common Mistake 3: Confusing LoRa with LoRaWAN

Point-to-point LoRa does not require a LoRaWAN gateway.

LoRaWAN does.

Choose the radio stack based on the network architecture.

Common Mistake 4: Treating the 2 MB Flash as Program Memory

Your normal SAMD21 sketch still targets:

The W25Q16 is external storage.

Common Mistake 5: Forgetting the Antenna

The LoRa module is not useful without an antenna appropriate to the operating band.

Fit the correct antenna before normal radio operation.

Common Mistake 6: Assuming USB Host Works in Every Power Mode

Current Arduino documentation requires:

for host mode.

Common Mistake 7: Drawing Too Much GPIO Current

The board-level maximum is:

so use external drivers for loads.

Quick Digital Reference

Quick Analog Reference

Quick Communications Reference

Final Thoughts

The MKR WAN 1310 combines a familiar SAMD21 Arduino with a purpose-built low-power LoRa subsystem.

Its strongest features are:

The most important pinout rules are:

For remote telemetry, the key design question is not simply whether the board can send LoRa packets. It is choosing the correct regional frequency plan, antenna, power strategy and network architecture.

For another SAMD21 MKR board with Wi-Fi instead of LoRa, see our MKR WiFi 1010 pinout guide. For a storage/audio-oriented SAMD21 board, see the MKR Zero pinout guide.