README.md
MicroPython Port To The Nordic Semiconductor nRF Series
This is a port of MicroPython to the Nordic Semiconductor nRF series of chips.
Supported Features
- UART
- SPI
- LEDs
- Pins
- ADC
- I2C
- PWM (nRF52 only)
- Temperature
- 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
Tested Hardware
- nRF51
- micro:bit
- PCA10000 (dongle)
- PCA10001
- PCA10028
- PCA10031 (dongle)
- WT51822-S4AT
- nRF52832
- nRF52840
- nRF9160
Compile and Flash
Prerequisite steps for building the nrf port:
git clone <URL>.git micropython
cd micropython
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 submodules
make
make deploy
Alternatively the target board could be defined:
make submodules
make BOARD=pca10040
make BOARD=pca10040 deploy
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
the compilation:
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:
./drivers/bluetooth/download_ble_stack.sh
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 bluetooth_conf.h
.
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 import
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
from.
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
Enable MICROPY_VFS_FAT
As the 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_VFS_FAT 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
in mpconfigport.h.
For example:
make BOARD=pca10040 MICROPY_VFS_FAT=1
Target Boards and Make Flags
Target Board (BOARD) | Bluetooth Stack (SD) | Bluetooth Support | Bootloader | Default Flash Util |
---|---|---|---|---|
microbit | s110 | Peripheral | PyOCD | |
pca10000 | s110 | Peripheral | Segger | |
pca10001 | s110 | Peripheral | Segger | |
pca10028 | s110 | Peripheral | Segger | |
pca10031 | s110 | Peripheral | Segger | |
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 | |
ibk_blyst_nano | s132 | Peripheral and Central | IDAP | |
idk_blyst_nano | s132 | Peripheral and Central | IDAP | |
blueio_tag_evim | s132 | Peripheral and Central | IDAP | |
evk_nina_b1 | s132 | Peripheral and Central | Segger | |
pca10056 | s140 | Peripheral and Central | Segger | |
pca10059 | s140 | Peripheral and Central | OpenBootloader | nrfutil |
particle_xenon | s140 | Peripheral and Central | Black Magic Probe | |
nrf52840-mdk-usb-dongle | s140 | Peripheral and Central | OpenBootloader | nrfutil |
pca10090 | None (bsdlib.a) | None (LTE/GNSS) | Segger | |
actinius_icarus | None (bsdlib.a) | None (LTE/GNSS) | Segger |
IDAP-M/IDAP-Link Targets
Install the necessary tools to flash and debug using IDAP-M/IDAP-Link CMSIS-DAP Debug JTAG:
IDAPnRFProg for Linux IDAPnRFProg for OSX IDAPnRFProg for Windows
Segger Targets
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.
PyOCD/OpenOCD Targets
Install the necessary tools to flash and debug using OpenOCD:
sudo apt-get install openocd
sudo pip install pyOCD
Black Magic Probe Targets
This requires no further dependencies other than arm-none-eabi-gdb
.
make deploy
will use gdb to load and run new firmware. See
this guide
for more tips about using the BMP with GDB.
nRFUtil Targets
Install the necessary Python packages that will be used for flashing using the bootloader:
sudo pip install nrfutil
sudo pip install intelhex
The intelhex
provides the hexmerge.py
utility which is used by the Makefile
to trim of the MBR in case SoftDevice flashing is requested.
nrfutil
as flashing backend also requires a serial port paramter to be defined
in addition to the deploy
target of make. For example:
make BOARD=nrf52840-mdk-usb-dongle NRFUTIL_PORT=/dev/ttyACM0 deploy
If the target device is connected to /dev/ttyACM0
serial port, the
NRFUTIL_PORT
parameter to make can be elided as it is the default serial
port set by the Makefile.
When enabling Bluetooth LE, as with the other flash utils, the SoftDevice
needs to be flashed in the first firmware update. This can be done by issuing
the sd
target instead of deploy
. For example:
make BOARD=nrf52840-mdk-usb-dongle SD=s140 NRFUTIL_PORT=/dev/ttyACM0 sd
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:
- NUS Console for Linux (recommended)
- WebBluetooth REPL (experimental)
Other:
- 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.
Pin numbering scheme for nrf52840-based boards
Software Pins 0-31 correspond to physical pins 0.x and software Pins 32-47 correspond to physical pins 1.x.
Example:
Pin(47)
would be 1.15 on the PCA10059