Skip to main content

Getting Started with FoBE Quill nRF52840 Mesh

FoBE Quill nRF52840 Mesh

Introduction​

The FoBE Quill nRF52840 Mesh is a compact and versatile development platform for IoT solutions. It combines Nordic's high-end multiprotocol SoC, the nRF52840, with Semtech's ultra-low-power sub-GHz radio transceiver, the SX1262. Designed for IoT applications, it offers a comprehensive wireless connectivity solution, supporting protocols such as Bluetooth 5, Thread, Zigbee, IEEE 80.2.15.4, and LoRa®.

This development board is feature-rich, including a battery charger, dedicated power path management, an ultra-low quiescent current DC-DC converter, a 1.14-inch color IPS display, user-programmable LEDs and buttons, an MFP expansion connector, a reversible USB-C connector, and header sockets for easy expansion.

Tech specs​

BoardNameFoBE Quill nRF52840 Mesh
SKUF1101
MicrocontrollerNordic nRF52840 (64 MHz Arm® Cortex-M4 with FPU)
USBUSB-C®Native in the nRF52840 Processor
PinsDigital I/O Pins20
Analog input Pins8 (12-bit, 200 ksps)
PWM Pins4x 4-channel
CommunicationUARTYes, 2x with EasyDMA
I2CYes, 2x compatible 2-wire master/slave
SPIYes, 4x master/3x slave with EasyDMA
CANNo
PowerCircuit operating voltage3.3 V
Input voltage (VIN)3.7 - 5 V
DC Current per I/O Pin15 mA
Clock speedSoCup to 64MHz
MemoryIntegrated1024 kB ROM, 256 kB SRAM
WirelessIntegratedBluetooth® 5, Thread, Zigbee, IEEE 802.15.4, NFC-A Tag, 2.4 GHz proprietaryEmbedded SMD ceramic antenna
SX1262 on BoardLoRa® (470 MHz for Model SLT, 868 - 915 MHz for Model SHT)iPEX-U.FL connector for sub-GHz external antenna
DisplaySize1.14 inch
PanelTFT LCD, Color
Resolution240 x 135 pixels
DriverST7789V
ButtonsResetYes, 1x
UserYes, 1x
LEDsUserYes, 1x Blue
ChargingYes, 1x Orange
ConnectivityBattery3.7 V Rechargeable LiPo/Li-ion, JST PH2.0 2-Pin
MFP (Multi-Function Port)JST SH1.0 6-Pin
Debugger (ARM Serial Wire Debug)2.54mm pitch pin header
DimensionsWidth60.96 mm
Length22.86 mm

Hardware diagram​

The following figure illustrates the FoBE Quill nRF52840 Mesh hardware diagram.

FoBE Quill nRF52840 Mesh Hardware Diagram

Mechanical dimensions​

FoBE Quill nRF52840 Mesh is a single-sided 60.96mm x 20.32mm (2.4" x 0.9") 1.6mm thick PCB with a USB Type-C port and dual rows of through-hole pins.

FoBE Quill nRF52840 Mesh Mechanical Dimensions

Power supply​

The FoBE Quill nRF52840 Mesh is designed to be powered by a battery and includes charging circuitry for lithium batteries. The charger can be powered from a wall adapter via the USB Type-C connector. The incoming USB voltage is routed exclusively to the charger IC, which monitors the battery and stops charging when it's full or if the temperature is too high (this requires soldering a thermistor to the NTC test point). The output from the charger then powers the development kit through a step-down converter.

A high-efficiency step-down converter (TPS62825) with a low quiescent current generates the 3.3V rail. This power supply powers the entire development kit and connected peripheral modules, supporting a maximum current of 2A.

Peripheral Power​

PERI_3V3 is a switchable 3.3V power supply that can be controlled by the MCU to cut off power to the MFP (Multi-Function Port) during idle periods, thus saving power. PERI_3V3 is controlled by the P1.03 GPIO on the SoC.

  • Set P1.03=1 to turn PERI_3V3 on.
  • Set P1.03=0 to turn PERI_3V3 off.

DISPLAY_EN and DISPLAY_BLK are used to control the display power and backlight, respectively. They are controlled by the P0.07 and P0.27 GPIOs on the SoC.

  • Set P0.07=0 to turn DISPLAY_EN on.
  • Set P0.07=1 to turn DISPLAY_EN off.
  • Set P0.27=0 to turn DISPLAY_BLK on.
  • Set P0.27=1 to turn DISPLAY_BLK off.

Power consumption​

Power consumption measurements were performed while powering the board with a simulated 3.7V lithium battery.

ModeAverage Current
SoC in sleep mode, all peripherals off< 18uA
SoC in active mode, all peripherals on, SX1262 in RX mode< 40mA
SoC in active mode, all peripherals on, SX1262 in TX mode< 140mA

Voltage measurement​

Battery voltage is measured using a voltage divider with high-precision thick film resistors. The high-side resistor (R1) is 1M Ohm, and the low-side resistor (R2) is 1.5M Ohm. The SoC's P0.05 GPIO is connected to the measurement point.

For a voltage divider circuit with two resistors, R1 and R2, in series, where Vin is the input voltage (battery voltage) and Vout is the voltage across R2 (measured by the ADC):

Vout = Vin * (R2 / (R1 + R2))

In this case: Vout = Vin * (1.5M / (1M + 1.5M)) = Vin * 0.6

Therefore: Vin = Vout / 0.6 = Vout * 1.667

By reading the voltage at the measurement point with the ADC, the battery voltage can be calculated by multiplying the measured voltage by 1.667.

General purpose I/Os​

There are up to 20 multi-function General Purpose I/Os (GPIOs) available on the header pins, 6 of which can be used as ADC inputs. These GPIOs operate at a 3.3V logic level. Any GPIO can be mapped to a digital peripheral (such as UART, SPI, TWI, PDM, I2S, QSPI, PWM, and QDEC) for layout flexibility.

The MFP provides an additional 4 GPIO pins. Two of these can be connected to an NFC antenna, used with modules supporting the MFP interface, or configured as two I2C channels.

Display​

The FoBE Quill nRF52840 Mesh features an on-board 1.14-inch full-color IPS display, driven by an ST7789V chip and mounted on a PETG bracket. It connects to the development board via an FPC (Flexible Printed Circuit) and has a resolution of 135 x 240 pixels with a maximum brightness of 400 cd/m².

Buttons and LEDs​

There are two buttons and one blue LED connected to dedicated GPIOs on the nRF52840 SoC. The following table shows the connections:

ComponentGPIO PinActive state
Reset ButtonP0.18Low
USR ButtonP1.10Low
USR LEDP0.14High

Sub-GHz Radio​

The FoBE Quill nRF52840 Mesh board features an on-board sub-GHz radio module based on the Semtech SX1262. It supports LoRa and (G)FSK modulation and operates in the 433 MHz, 868 MHz, and 915 MHz frequency bands (depending on the model). An integrated 1.8V TCXO ensures excellent stability across temperature variations.

Key specifications include a low active receive current of just 4.2 mA, a maximum transmit power of up to +22 dBm, and high sensitivity down to -148 dBm, providing excellent interference immunity.

The module connects to the nRF52840 SoC via SPI for long-range wireless communication:

SX1262 PinGPIO PinActive state
MISOP0.19
MOSIP0.21
SCKP0.23
NSSP1.01Low
RSTP1.06Low
BUSYP1.04High
DIO1P1.02High
RXENP0.25High

Antenna​

Bluetooth and 2.4 GHz Antenna​

The FoBE Quill nRF52840 Mesh board has an embedded SMD ceramic antenna for the nRF52840 SoC, which supports Bluetooth and 2.4 GHz communication.

Sub-GHz Antenna​

The FoBE Quill nRF52840 Mesh board has an iPEX-U.FL connector for an external sub-GHz antenna.

Debug interface​

The FoBE Quill nRF52840 Mesh board provides a debug interface via the SWD (Serial Wire Debug) port. This allows developers to program and debug their applications using compatible tools and IDEs.

FoBE Quill nRF52840 Mesh Debug Interface

Light up the board​

Prerequisite​

Before you begin, please make sure you have the following items:

Hardware​

  • FoBE Quill nRF52840 Mesh board
  • USB-C Cable (must support data transfer)
  • 3.7V Li-Ion/LiPo Battery (optional, for battery-powered applications)
  • Sub-GHz Antenna (required if your program enables sub-GHz communication to avoid damaging the module)

Software​

You can use various IDEs for programming the FoBE Quill nRF52840 Mesh.

Setup the board​

Follow these steps to get your FoBE Quill nRF52840 Mesh board up and running:

  1. Connect the Sub-GHz antenna to the iPEX-U.FL connector on the board (if applicable).
warning

If you are using the Sub-GHz radio, you must connect an appropriate antenna to the iPEX-U.FL connector. Operating the radio without an antenna may cause permanent damage.

  1. Connect the board to your computer using a USB-C cable.
important

Ensure your USB cable supports data transfer (USB 2.0 or higher). Charge-only cables will not work.

  1. Launch the Arduino IDE.

  2. Install the board package.

    Follow documentation Platform Arduino to install the FoBE Quill nRF52840 Mesh board package.

  3. Select the board and port.

    • Click the board selector in the top left corner of the Arduino IDE.
    • Select the port corresponding to your FoBE Quill nRF52840 Mesh board.
    • Select FoBE Quill nRF52840 Mesh from the list of available boards.
Guide Screenshot

  1. Open an example sketch.

    • Navigate to File > Examples > 01.Basics > Blink.
Guide Screenshot

  1. Upload the sketch.

    • Click the Upload button (right arrow icon) in the Arduino IDE toolbar.
    • Wait for the upload process to complete.
warning

If you want to use the USB Serial for printing output, ensure you enable "Serial (CDC)" under Tools > Print Port. Then, add the following line to the top of your sketch:

#include <Adafruit_TinyUSB.h>
Guide Screenshot

Once the upload is complete, the onboard blue LED should start blinking, indicating that your board is successfully set up and running the example sketch.

You Did a Great Job

Advanced usage​

Measuring battery status​

The battery voltage can be measured using the ADC (Analog-to-Digital Converter) on the nRF52840 SoC. The measurement is performed through a voltage divider circuit, as described in the Power Supply section.

Measuring battery voltage​

#include <Arduino.h>
#include <Adafruit_TinyUSB.h>

void setup()
{
  // Initialize the battery voltage pin
  pinMode(PIN_VBAT, INPUT);
  analogReference(AR_INTERNAL_3_0);
  analogReadResolution(12);

  Serial.begin(115200);
}

void loop()
{
  // Read battery voltage
  int raw = analogRead(PIN_VBAT);
  float vref = 3.0; // ADC reference voltage
  float vmeas = raw * vref / 4095.0; // Measured voltage at ADC pin
  float voltage = vmeas * 1.667; // Calculate actual battery voltage using voltage divider ratio
  Serial.print("Battery voltage: ");
  Serial.print(voltage);
  Serial.println(" V");
  delay(1000);
}

Reading charging status​

#include <Arduino.h>
#include <Adafruit_TinyUSB.h>

void setup()
{
  // Initialize the charging pin
  pinMode(PIN_CHARGING, INPUT);
  Serial.begin(115200);
}

void loop()
{
  // Read charging status
  int status = digitalRead(PIN_CHARGING);
  Serial.print("Charging status: ");
  Serial.println(status == LOW ? "Charging" : "Not Charging");
  delay(1000);
}

Drawing on the display​

The TFT display on the FoBE Quill nRF52840 Mesh can be controlled using the Adafruit GFX library. You can draw shapes, text, and images on the display.

important

Make sure to install the Adafruit GFX and Adafruit ST7735 and ST7789 Library libraries in your Arduino IDE before using the following code.

#include <Arduino.h>
#include <Adafruit_TinyUSB.h>
#include <Adafruit_GFX.h>
#include <Adafruit_ST7789.h>
#include <SPI.h>

// Setup ST7789 display
Adafruit_ST7789 tft = Adafruit_ST7789(&SPI1, PIN_ST7789_NSS, PIN_ST7789_RS, PIN_ST7789_RESET);

void setup()
{
  // Initialize the TFT_EN and TFT_BLK pins as outputs
  pinMode(PIN_TFT_EN, OUTPUT);
  pinMode(PIN_TFT_BLK, OUTPUT);

  // Turn on the display power
  digitalWrite(PIN_TFT_EN, LOW);
  // Turn on the backlight
  digitalWrite(PIN_TFT_BLK, LOW);

  // Initialize SPI
  SPI1.begin();
  // Initialize USB Serial
  Serial.begin(115200);

  // Initialize the display
  Serial.println(F("Initializing ST7789 display..."));
  tft.init(135, 240);
  tft.setRotation(1);
  Serial.println(F("Initialized"));

  // Fill the screen with black
  tft.fillScreen(ST77XX_BLACK);
  tft.setTextWrap(false);
  tft.fillScreen(ST77XX_BLACK);
  tft.setCursor(0, 30);
  tft.setTextColor(ST77XX_WHITE);
  tft.setTextSize(2);
  tft.println("Hello FoBE!");

  Serial.println(F("Display update complete"));
}

void loop() {}

Power Consumption Verification​

To verify the power consumption of the FoBE Quill nRF52840 Mesh, you can use a power analyzer or a multimeter to measure the current drawn by the board in different modes (e.g., sleep, active).

You can follow the Meshtastic application guide to set up a low-power scenario for measurement.

Applications​

Meshtastic​

Meshtastic is a popular open-source project that allows you to create an off-grid, decentralized mesh network built to run on affordable, low-power devices.

The FoBE Quill nRF52840 Mesh is compatible with Meshtastic, allowing you to build your own mesh network using this development board.

Flashing firmware​

This tutorial will guide users to flash the FoBE Quill nRF52840 Mesh to the Meshtastic version, for those who want to use the Meshtastic network.

Preparation​

  • FoBE Quill nRF52840 Mesh Board x 1
  • USB-C cable x 1
  • Computer with Python 3 installed

Wiring​

Connect the FoBE Quill nRF52840 Mesh to your computer using a USB-C cable.

Flash Meshtastic firmware​

Download the latest firmware from the Firmware Hub.

Double click the Reset button, there should be a FoBE Boot drive on your PC.

Guide Screenshot

Drag the firmware-fobe_quill_nrf52840_mesh-2.7.3.cf574c7.uf2 file to the drive. The installation will run automatically, then the drive will disappear.

Now you can use the FoBE Quill nRF52840 Mesh with the Meshtastic network. You can use the Meshtastic app to configure your device and start using it.

More information can be found in the Meshtastic documentation.

Resources​

[PDF] FoBE Quill nRF52840 Mesh Datasheet

[PDF] FoBE Quill nRF52840 Mesh Schematic

[PDF] FoBE Quill nRF52840 Mesh Dimension

[OBJ] FoBE Quill nRF52840 Mesh 3D Model