5.2 KiB
@defgroup boards_nrf52840dongle nRF52840-Dongle @ingroup boards @brief Support for the nRF52840-Dongle
General information
The nRF52840-Dongle is a bare USB-stick shaped device that houses barely anything than the nRF52840 itself, which offers BLE and 802.15.4 and USB connectivity.
Unlike similar sticks (like the @ref boards_nrf52840-mdk), it features no dedicated programmer hardware but relies on direct USB communication with a built-in bootloader.
The board features two LEDs (LD1: green, LD2: RGB), a user (SW1) and a reset button as well as 15 configurable external pins.
Hardware
| MCU | nRF52840 |
|---|---|
| Family | ARM Cortex-M4 |
| Vendor | Nordic Semiconductor |
| RAM | 256 KiB |
| Flash | 1 MiB |
| Frequency | 64 MHz |
| FPU | yes |
| Timers | 5 (32-bit) |
| RTC | 3 |
| ADCs | 1x 12-bit (8 channels) |
| UARTs | 2 |
| SPIs | 4 masters/3 slaves |
| I2Cs | 2 |
| I2S | 1 |
| PWM | 4*4 Channels |
| Radio | 2.4GHz BLE compatible, -20 dBm to +8 dBm output, -95 dBm RX sensitivity |
| Vcc | 1.7V - 5.5V |
| MCU Manual | Manual |
| Dongle Documentation | Documentation |
Quick start
- Plug into a USB port.
$ make BOARD=nrf52840dongle -C examples/basic/saul flash term- See Flash the board if anything goes wrong.
> saul write 2 10 40 10- The LED glows in a soft turquise.
Flash the board
The board is flashed using its on-board boot loader; the proprietary
nrfutil program needs to
be installed, and nrfutil install nrf5sdk-tools needs to be executed. Note
that nrfutil, even when not running the "install" command, will install itself
into ~/.nrfutil. The older Python based version of nrfutil is no longer
maintained by Nordic, and has become dysfunctional on Python 3.11.
The nrfutil can turn the binary into a suitable zip file and send it to the
bootloader. The process is automated in the usual make flash target.
If RIOT is already running on the board, it will automatically reset the CPU and enter the bootloader. If some other firmware is running or RIOT crashed, you need to enter the bootloader manually by pressing the board's reset button.
Readiness of the bootloader is indicated by LD2 pulsing in red.
Accessing STDIO
The usual way to obtain a console on this board is using an emulated USB serial port (CDC-ACM).
This is available automatically using the stdio_cdc_acm module,
unless any other stdio module is enabled.
On Linux systems with ModemManager < 1.10 installed,
make term will, in some setups, fail for a few seconds after the device has come up.
This is fixed in its 1.12.4 version,
but should not be more than a short annoyance in earlier versions.
To ease debugging, pins 0.13 and 0.15 are configured as RX and TX, respectively. They provide stdio if no CDC-ACM is disabled, and can be used as a custom UART otherwise.