Getting Started with NuttX – Nucleo STM32F303 (Arch Linux)
Here we will try to set up a functional Nuttx environment on a STM32F303 Nucleo-64 evaluation board on Arch Linux OS.
We will install the required software components, configure the board in order to be able to display the "hello world !" string on a serial terminal to the emulated ST-LINK/V2-1 serial port (through the USB cable).
Installing the ARM tool chain
Install the following Arch software packages:
# pacman -S gdb arm-none-eabi-gcc arm-none-eabi-gdb python-pyserial openocd
Some requirements are fulfilled by AUR, namely:
- kconfig-frontends
- genromfs
Packaging from AUR, despite being very simple, is out of scope of this document. Please refer to Arch Wiki and install these above packages.
Install Nuttx
$ mkdir nucleo; cd nucleo $ git clone https://bitbucket.org/nuttx/nuttx $ git clone https://bitbucket.org/nuttx/apps $ cd nuttx $ tools/configure.sh nucleo-f303re:hello
Now let's adapt the provided configuration to our needs:
$ cd .. $ make menuconfig
Although they have already been set in this configuration, let's review the important options here:
- Build Setup / Optimization Level: select "Suppress Optimization" in order to step into your code with the debugger.
- Build Setup / Debug Options: select "Generate Debug Symbols" in order to debug with gdb
- System Type / STM32 Peripheral Support: select "USART2" which is conncted to the STLINK serial interface through the USB bridge (will be seen as /dev/ttyACM0 in Linux)
- RTOS Features / Tasks and Scheduling / Application entry point: type "hello_main" which is the main function of the hello example
- RTOS Features / Files and I/O: select "Enable /dev/console" to enable console at boot time
- Device Drivers / Serial Driver Support / Serial console: select "USART2"
- Device Drivers / Serial Driver Support / USART2 Configuration: review serial parameters (default is fine)
- Application Configuration / Examples: select ""Hello, World!" example"
Now compile Nuttx (output truncated):
$ make ... LD: nuttx make[1]: Leaving directory '/home/myhome/projets/myproject/nuttx/arch/arm/src' CP: nuttx.hex
One can see the firmware nuttx.hex has been successfully generated.
Flash & debug with openocd and gdb
The good thing with the nucleo kit is that it embarks the latest st-link/V2-1 which may be used as a JTAG programmer/debugger, and also a USB to serial bridge which is already routed to the STM32 UART1. Therefore one can use it to redirect sdtout and the Nuttx console.
In the nuttx directory, perpare a openocd.cfg file with the following:
# This is an ST NUCLEO F303RE board with a single STM32F303RET6 chip. source [find interface/stlink-v2-1.cfg] source [find target/stm32f3x.cfg] # use hardware reset, connect under reset reset_config srst_only srst_nogate init reset init halt
Also you may prepare a .gdbinit file with:
target remote localhost:3333
It will allow gdb to automatically connect to the openocd server.
udev rules:
Make sure your udev rules allow regular user to read/write on ttyUSB and ttyACM devices. For example in /etc/udev/rules.d, create a file 99-myrules.rules with the following content:
SUBSYSTEM!="tty", GOTO="serial_end"
ACTION=="add", ATTRS{idProduct}=="6001", ATTRS{idVendor}=="0403", MODE="666"
LABEL="serial_end"
ACTION!="add|change", GOTO="openocd_rules_end"
SUBSYSTEM!="usb|tty|hidraw", GOTO="openocd_rules_end"
# STM32_STLink v2-1
ATTRS{idProduct}=="374b", ATTRS{idVendor}=="0483", MODE="666"
LABEL="openocd_rules_end"
Make sure your STLINK is recognized properly. Unplug and plug again your STLINK to the USB connector.
Check that it is detected properly:
ls -l /dev/ttyA* crw-rw-rw- 1 root uucp 166, 0 25 oct. 08:11 /dev/ttyACM0
let's try to connect to STM32
Now connect your ST-LINK with the USB cable and start openocd server in a dedicated terminal session (cd in nuttx before):
$ openocd Open On-Chip Debugger 0.9.0 (2016-04-27-23:18) Licensed under GNU GPL v2 For bug reports, read http://openocd.org/doc/doxygen/bugs.html Info : auto-selecting first available session transport "hla_swd". To override use 'transport select <transport>'. adapter speed: 1000 kHz adapter_nsrst_delay: 100 Info : The selected transport took over low-level target control. The results might differ compared to plain JTAG/SWD none separate srst_only separate srst_nogate srst_open_drain connect_deassert_srst Info : Unable to match requested speed 1000 kHz, using 950 kHz Info : Unable to match requested speed 1000 kHz, using 950 kHz Info : clock speed 950 kHz Info : STLINK v2 JTAG v25 API v2 SWIM v14 VID 0x0483 PID 0x374B Info : using stlink api v2 Info : Target voltage: 3.239448 Info : stm32f3x.cpu: hardware has 6 breakpoints, 4 watchpoints Info : Unable to match requested speed 1000 kHz, using 950 kHz Info : Unable to match requested speed 1000 kHz, using 950 kHz adapter speed: 950 kHz target state: halted target halted due to debug-request, current mode: Thread xPSR: 0x01000000 pc: 0x08000438 msp: 0x200015d0 Info : Unable to match requested speed 8000 kHz, using 4000 kHz Info : Unable to match requested speed 8000 kHz, using 4000 kHz adapter speed: 4000 kHz
In another dedicated terminal session (cd in nuttx before), start dbg. It should automatically connect to openocd server:
$ arm-none-eabi-gdb nuttx
GNU gdb (GDB) 7.11.1
Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "--host=x86_64-pc-linux-gnu --target=arm-none-eabi".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from nuttx...done.
__start () at chip/stm32_start.c:243
243 {
(gdb)
Now load the firmware into the STM32. In gdb type "load":
(gdb) load Loading section .text, size 0x6044 lma 0x8000000 Loading section .ARM.exidx, size 0x8 lma 0x8006044 Loading section .data, size 0x5c lma 0x800604c Start address 0x8000434, load size 24744 Transfer rate: 21 KB/sec, 6186 bytes/write. (gdb)
Run the code. In gdb type "c" (continue).
The RED and GREEN LEDS should be both ON on the nucleo board.
To stop the code, press Ctlrl+C
For more information on openocd: http://openocd.org/doc/html/index.html
and for GNU gdb: https://www.chemie.fu-berlin.de/chemnet/use/info/gdb/gdb_toc.html
GNU Make doc may be also valuable: https://www.gnu.org/software/make/manual/make.html
Connect to the STLINK serial console
Open a new terminal and run the miniterm:
$ miniterm.py /dev/ttyACM0 115200 miniterm.py /dev/ttyACM0 115200 --- Miniterm on /dev/ttyACM0 115200,8,N,1 --- --- Quit: Ctrl+] | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---
Press the black RESET button on the nucleo board, one should see the following in the terminal window:
miniterm.py /dev/ttyACM0 115200 --- Miniterm on /dev/ttyACM0 115200,8,N,1 --- --- Quit: Ctrl+] | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H --- Hello, World!!
Congratulation! You are started with NuttX!