CircuitPython Port To The Nordic Semiconductor nRF52 Series¶
This is a port of CircuitPython to the Nordic Semiconductor nRF52 series of chips.
- RTC (Real Time Counter. Low-Power counter)
- BLE support including:
- Peripheral role
- Scanner role
- REPL over Bluetooth LE (optionally using WebBluetooth)
- ubluepy: Bluetooth LE module for CircuitPython
- 1 non-connectable advertiser while in connection
Compile and Flash¶
Prerequisite steps for building the nrf port:
git clone <URL>.git circuitpython cd circuitpython git submodule update --init make -C mpy-cross
By default, the feather52 (nRF52832) is used as compile target. To build and flash issue the following command inside the ports/nrf/ folder:
make make flash
Alternatively the target board could be defined:
make BOARD=pca10056 make flash
Compile and Flash with Bluetooth Stack¶
First prepare the bluetooth folder by downloading Bluetooth LE stacks and headers:
If the Bluetooth stacks has been downloaded, compile the target with the following command:
make BOARD=pca10040 SD=s132
The make sd will trigger a flash of the bluetooth stack before that application is flashed. Note that make sd will perform a full erase of the chip, which could cause 3rd party bootloaders to also be wiped.
make BOARD=pca10040 SD=s132 sd
Note: further tuning of features to include in bluetooth or even setting up the device to use REPL over Bluetooth can be configured in the
Target Boards and Make Flags¶
Target Board (BOARD) | Bluetooth Stack (SD) | Bluetooth Support | Flash Util ———————|————————-|————————|——————————- pca10040 | s132 | Peripheral and Scanner | Segger feather52 | s132 | Peripheral and Scanner | UART DFU pca10056 | s140 | Peripheral and Scanner | Segger
Install the necessary tools to flash and debug using Segger:
note: On Linux it might be required to link SEGGER’s
libjlinkarm.so inside nrfjprog’s folder.
sudo apt-get install build-essential libffi-dev pkg-config gcc-arm-none-eabi git python python-pip git clone https://github.com/adafruit/Adafruit_nRF52_Arduino.git cd Adafruit_nRF52_Arduino/tools/nrfutil-0.5.2/ sudo pip install -r requirements.txt sudo python setup.py install
make flash and make sd will not work with DFU targets. Hence, dfu-gen and dfu-flash must be used instead.
- dfu-gen: Generates a Firmware zip to be used by the DFU flash application.
- dfu-flash: Triggers the DFU flash application to upload the firmware from the generated Firmware zip file.
Example on how to generate and flash feather52 target:
make BOARD=feather52 SD=s132 make BOARD=feather52 SD=s132 dfu-gen make BOARD=feather52 SD=s132 dfu-flash
Bluetooth LE REPL¶
The port also implements a BLE REPL driver. This feature is disabled by default, as it will deactivate the UART REPL when activated. As some of the nRF devices only have one UART, using the BLE REPL free’s the UART instance such that it can be used as a general UART peripheral not bound to REPL.
The configuration can be enabled by editing the
bluetooth_conf.h and set
MICROPY_PY_BLE_NUS to 1.
When enabled you have different options to test it:
- nRF UART application for IPhone/Android
WebBluetooth mode can also be configured by editing
bluetooth_conf.h and set
BLUETOOTH_WEBBLUETOOTH_REPL to 1. This will alternate advertisement between Eddystone URL and regular connectable advertisement. The Eddystone URL will point the phone or PC to download WebBluetooth REPL (experimental), which subsequently can be used to connect to the Bluetooth REPL from the PC or Phone browser.