How to Use Adafruit Feather nRF52840: Examples, Pinouts, and Specs

The Adafruit Feather nRF52840 is a versatile and compact development board that harnesses the power of the Nordic Semiconductor nRF52840 System-on-Chip (SoC). This board is part of the Feather ecosystem, known for its portable and modular design. With an ARM Cortex-M4 CPU, built-in Bluetooth Low Energy (BLE), and a rich set of peripherals, the Feather nRF52840 is ideal for Internet of Things (IoT) projects, wearable devices, and wireless applications.

• Wearable electronics
• Wireless sensor networks
• IoT connected devices
• Bluetooth-enabled products
• Prototyping for embedded systems

• Microcontroller: Nordic nRF52840 SoC
• CPU: 32-bit ARM Cortex-M4 with FPU
• Clock Speed: 64 MHz
• Flash Memory: 1 MB
• SRAM: 256 KB
• Bluetooth: BLE 5.0
• I/O Pins: 21 GPIO pins
• Voltage Supply: 3.3V regulator with 1A peak current output
• Battery: Li-Po single cell, 3.7V, 2-pin JST-PH connector
• USB: Native USB support with USB bootloader and serial port debugging

1. Powering the Board:

   • You can power the Feather nRF52840 via USB or through the JST-PH battery connector.
   • Ensure that the power supply is within the recommended voltage range.

2. Connecting Peripherals:

   • Use the GPIO pins to connect sensors, actuators, or other modules.
   • For I2C devices, connect SDA and SCL pins accordingly.
   • For SPI communication, use MISO, MOSI, and SCK pins.

3. Programming the Board:

   • The board can be programmed using the Arduino IDE or other development environments that support the nRF52840.
   • Select the appropriate board from the tools menu in the Arduino IDE.

• Always disconnect the board from power sources before making or altering connections.
• Use a current limiting resistor when connecting LEDs to GPIO pins.
• When using the board's Bluetooth functionality, ensure compliance with local regulations regarding wireless transmission.
• Avoid exposing the board to static electricity or physical stress.

• Board Not Recognized by Computer:

  • Ensure the USB cable is properly connected and functional.
  • Check that the correct drivers are installed on your computer.

• Failure to Upload Sketches:

  • Verify the correct board and port are selected in the Arduino IDE.
  • Press the reset button on the board twice quickly to enter bootloader mode if necessary.

• Bluetooth Connectivity Issues:

  • Ensure the BLE stack and libraries are correctly configured in your development environment.
  • Check the antenna and ensure there's no physical obstruction or interference.

• If the board is not recognized, try using a different USB port or cable.
• For upload failures, double-check the code for errors and ensure the bootloader is up to date.
• For Bluetooth issues, test with a simple BLE example to isolate the problem.

Here's a simple example of how to blink an LED using the Adafruit Feather nRF52840 with the Arduino IDE:

// Define the LED pin
#define LED_PIN 13

void setup() {
  // Initialize the LED pin as an output
  pinMode(LED_PIN, OUTPUT);
}

void loop() {
  // Turn the LED on
  digitalWrite(LED_PIN, HIGH);
  // Wait for 1 second
  delay(1000);
  // Turn the LED off
  digitalWrite(LED_PIN, LOW);
  // Wait for 1 second
  delay(1000);
}

Remember to select the Adafruit Feather nRF52840 board from the Arduino IDE before uploading the sketch.

Note: This code is for demonstration purposes and assumes the use of the onboard LED connected to pin 13. If you're using an external LED, ensure it's connected with a suitable current-limiting resistor.