Feather M0 LoRa

Overview

The Adafruit Feather M0 Lora is a thin, light ARM development boards with an onboard battery connector and charger for 3.7 V lithium polymer batteries, charging status indicator and user LEDs, native USB connector, 20 I/O pins, and a LoRa radio module from Semtech.

Hardware

ATSAMD21G18A ARM Cortex-M0+ processor at 48 MHz
32.768 kHz crystal oscillator
256 KiB flash memory and 32 KiB of RAM
Battery connector and charger for 3.7 V lithium polymer batteries
Charging indicator LED
User LED
Reset button
Native USB port
SX127x LoRa radio

Supported Features

The adafruit_feather_m0_lora board supports the hardware features listed below.

on-chip / on-board: Feature integrated in the SoC / present on the board.
2 / 2: Number of instances that are enabled / disabled.
Click on the label to see the first instance of this feature in the board/SoC DTS files.
vnd,foo: Compatible string for the Devicetree binding matching the feature.
Click on the link to view the binding documentation.

`adafruit_feather_m0_lora/samd21g18a` target

Type	Location	Description	Compatible
CPU	on-chip	ARM Cortex-M0+ CPU1	`arm,cortex-m0+`
ADC	on-chip	Atmel SAM0 family ADC1	`atmel,sam0-adc`
ARM architecture	on-chip	Atmel SAM0 multi-protocol (UART, SPI, I2C) SERCOM unit3	`atmel,sam0-sercom`
ARM architecture	on-chip	For locating the Device ID (serial number) on Atmel SAM0 devices1	`atmel,sam0-id`
Clock control	on-chip	Atmel SAM0 Main Clock Controller (MCLK)1	`atmel,sam0-mclk`
Clock control	on-chip	Atmel SAMD0 Generic Clock Controller (GCLK)1	`atmel,sam0-gclk`
Counter	on-chip	Atmel SAM0 basic timer counter (TC) operating in 32-bit wide mode2	`atmel,sam0-tc32`
DAC	on-chip	Atmel SAM0 family DAC1	`atmel,sam0-dac`
DMA	on-chip	Atmel SAM0 DMA controller1	`atmel,sam0-dmac`
Flash controller	on-chip	Atmel SAM0 NVMC (Non-Volatile Memory Controller)1	`atmel,sam0-nvmctrl`
GPIO & Headers	on-chip	SAM0 GPIO PORT node2	`atmel,sam0-gpio`
I2C	on-chip	Atmel SAM0 series SERCOM I2C1	`atmel,sam0-i2c`
Interrupt controller	on-chip	ARMv6-M NVIC (Nested Vectored Interrupt Controller) controller1	`arm,v6m-nvic`
Interrupt controller	on-chip	Atmel SAM0 series External Interrupt Controller1	`atmel,sam0-eic`
LED	on-board	Group of GPIO-controlled LEDs1	`gpio-leds`
LoRa	on-board	Semtech SX1276 LoRa Modem1	`semtech,sx1276`
MTD	on-chip	Flash node1	`soc-nv-flash`
MTD	on-board	Fixed partitions of a flash (or other non-volatile storage) memory1	`fixed-partitions`
Pin control	on-chip	Atmel SAM0 PINMUX2	`atmel,sam0-pinmux`
Pin control	on-chip	Atmel SAM0 Pinctrl Container1	`atmel,sam0-pinctrl`
RTC	on-chip	Atmel SAM0 RTC1	`atmel,sam0-rtc`
Serial controller	on-chip	Atmel SAM0 SERCOM UART driver1	`atmel,sam0-uart`
SPI	on-chip	Atmel SAM0 SERCOM SPI controller1	`atmel,sam0-spi`
SRAM	on-chip	Generic on-chip SRAM description1	`mmio-sram`
Timer	on-chip	ARMv6-M System Tick1	`arm,armv6m-systick`
USB	on-chip	Atmel SAM0 USB in device mode1	`atmel,sam0-usb`
Watchdog	on-chip	Atmel SAM0 watchdog1	`atmel,sam0-watchdog`

Connections and IOs

The Adafruit Feather M0 with LoRa radio module Learn site [1] has detailed information about the board including pinouts [2] and the schematic [3].

System Clock

The SAMD21 MCU is configured to use the 32.768 kHz external oscillator with the on-chip PLL generating the 48 MHz system clock.

Serial Port

The SAMD21 MCU has 6 SERCOM based USARTs. On the Adafruit Feather M0 with LoRa, SERCOM0 is the Zephyr console and is available on pins 0 (RX) and 1 (TX).

I2C Port

The SAMD21 MCU has 6 SERCOM based USARTs. On the Adafruit Feather M0 with LoRa, SERCOM3 is available on pin 20 (SDA) and pin 21 (SCL).

SPI Port

The SAMD21 MCU has 6 SERCOM based SPIs. On the Adafruit Feather M0 with LoRa, SERCOM4 is available on pin 22 (MISO), pin 23 (MOSI), and pin 24 (SCK).

USB Device Port

The SAMD21 MCU has a USB device port that can be used to communicate with a host PC. See the USB device support sample applications for more, such as the USB CDC-ACM sample which sets up a virtual serial port that echos characters back to the host PC.

LoRa Radio

The Semtech SX127x radio chip on the Adafruit Feather M0 with LoRa is attached to the SPI port (SERCOM4). Depending on the hardware version, 433MHz or 900MHz is supported.

Programming and Debugging

The Adafruit Feather M0 with LoRa ships with a BOSSA compatible SAM-BA bootloader. The bootloader can be entered by quickly tapping the reset button twice.

Flashing

Build the Zephyr kernel and the Hello World sample application:

west build -b adafruit_feather_m0_lora samples/hello_world

Connect the Adafruit Feather M0 with LoRa to your host computer using USB
Connect a 3.3 V USB to serial adapter to the board and to the host. See the Serial Port section above for the board’s pin connections.
Run your favorite terminal program to listen for output. Under Linux the terminal should be /dev/ttyACM0. For example:
```
$ minicom -D /dev/ttyACM0 -o
```
The -o option tells minicom not to send the modem initialization string. Connection should be configured as follows:
- Speed: 115200
- Data: 8 bits
- Parity: None
- Stop bits: 1
Tap the reset button twice quickly to enter bootloader mode
Flash the image:
```
west build -b adafruit_feather_m0_lora samples/hello_world
west flash
```
You should see “Hello World! adafruit_feather_m0_lora” in your terminal.