MicroPython Port To The Nordic Semiconductor nRF Series
This is a port of MicroPython to the Nordic Semiconductor nRF series of chips.
- PWM (nRF52 only)
- RTC (Real Time Counter. Low-Power counter)
- BLE support including:
- Peripheral role on nrf51 targets
- Central role and Peripheral role on nrf52 targets
- REPL over Bluetooth LE (optionally using WebBluetooth)
- ubluepy: Bluetooth LE module for MicroPython
- 1 non-connectable advertiser while in connection
Compile and Flash
Prerequisite steps for building the nrf port:
git clone <URL>.git micropython cd micropython git submodule update --init make -C mpy-cross
By default, the PCA10040 (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=pca10040 make BOARD=pca10040 flash
Compile without LTO enabled
As a space optimization, LTO (Link Time Optimization) has been enabled on all
targets in the nrf-port. The
-flto linker flag can be toggled easily by using
the argument LTO when building. The example below shows how to disable LTO for
make BOARD=pca10040 LTO=0
Note: There have been several issues with use of LTO in conjunction with GNU ARM Embedded Toolchain 7.2.1/4Q17. It's recommended to use a toolchain after this release, for example 7.3.1/2Q18 or 8.2.1/4Q18. The alternative would be to build the target using the LTO=0 as described above.
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
Compile with frozen modules
Frozen modules are Python modules compiled to bytecode and added to the firmware
image, as part of MicroPython. They can be imported as usual, using the
statement. The advantage is that frozen modules use a lot less RAM as the
bytecode is stored in flash, not in RAM like when importing from a filesystem.
Also, frozen modules are available even when no filesystem is present to import
To use frozen modules, put them in a directory (e.g.
freeze/) and supply
make with the given directory. For example:
make BOARD=pca10040 FROZEN_MPY_DIR=freeze
oofatfs module is not having header guards that can exclude the implementation compile time, this port provides a flag to enable it explicitly. The MICROPY_FATFS is by default set to 0 and has to be set to 1 if
oofatfs files should be compiled. This will be in addition of setting
MICROPY_VFS_FAT in mpconfigport.h.
make BOARD=pca10040 MICROPY_FATFS=1
Target Boards and Make Flags
|Target Board (BOARD)||Bluetooth Stack (SD)||Bluetooth Support||Flash Util|
|wt51822_s4at||s110||Peripheral||Manual, see datasheet for pinout|
|pca10040||s132||Peripheral and Central||Segger|
|feather52||s132||Peripheral and Central||Manual, SWDIO and SWCLK solder points on the bottom side of the board|
|arduino_primo||s132||Peripheral and Central||PyOCD|
|pca10056||s140||Peripheral and Central||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.
Install the necessary tools to flash and debug using OpenOCD:
sudo apt-get install openocd sudo pip install pyOCD
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.