[译]在不到2美元的开发板上运行Nuttx实时操作系统

原文: https://acassis.wordpress.com/2016/06/12/running-nuttx-on-a-less-than-u2-00-board/

几个月前我发现了一款便宜的微控制器 - STM32F103C8T6
我从AliExpress上购买仅花了1.96美元
收到货之后, 我实现了在板子上运行Nuttx, 并且向Mr. Greg(译者注: 应为Nuttx主要开发人员)提交了补丁，使Nuttx主线版本支持该板子

所以现在，任何人都能轻而易举地在STM32F103C8T6上运行Nuttx了
该教程将展示我是如何做到的，首先列出我们需要的物件:

  • STM32F103C8T6 最小开发板
  • STLinkV2下载器
  • 支持3.3V电压的USB-串口转换器
  • USB-MicroUSB数据线, 也就是平时给智能手机充电的那种
  • 运行Ubuntu/Debian Linux的电脑, 应该也能用Windows(Cygwin)或MacOS, 但我没试过

第一步安装编译工具
1) 安装交叉编译包

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$ sudo aptitude install gcc-arm-none-eabi ncurses-dev gperf flex bison libtool

2) 编译安装OpenOCD

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$ git clone http://repo.or.cz/r/openocd.git
$ cd openocd
$ ./bootstrap
$ ./configure --enable-internal-jimtcl --enable-maintainer-mode --disable-werror --disable-shared --enable-stlink --enable-jlink --enable-rlink --enable-vsllink --enable-ti-icdi --enable-remote-bitbang

完成后你将看到如下信息

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libjaylink configuration summary:
 - Package version ................ 0.1.0
 - Library version ................ 0:0:0
 - Installation prefix ............ /usr/local
 - Building on .................... x86_64-pc-linux-gnu
 - Building for ................... x86_64-pc-linux-gnu
OpenOCD configuration summary
--------------------------------------------------
MPSSE mode of FTDI based devices        yes (auto)
Segger J-Link JTAG Programmer           yes
ST-Link JTAG Programmer                 yes
TI ICDI JTAG Programmer                 yes
Keil ULINK JTAG Programmer              yes (auto)
Altera USB-Blaster II Compatible        yes (auto)
Versaloon-Link JTAG Programmer          yes
OSBDM (JTAG only) Programmer            yes (auto)
eStick/opendous JTAG Programmer         yes (auto)
Andes JTAG Programmer                   yes (auto)
USBProg JTAG Programmer                 yes (auto)
Raisonance RLink JTAG Programmer        yes
Olimex ARM-JTAG-EW Programmer           yes (auto)
CMSIS-DAP Compliant Debugger            yes (auto)

编译并安装

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$ make
$ sudo make install

下一步将下载编译Nuttx
1) 下载Nuttx核心和附带程序

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$ mkdir NuttX
$ cd NuttX
$ git clone https://bitbucket.org/nuttx/nuttx
$ git clone https://bitbucket.org/nuttx/apps
$ git clone https://bitbucket.org/nuttx/tools

2) 编译Kconfig Frontend(编译NuttX需要它):

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cd tools/kconfig-frontends
./configure --enable-mconf
make
make install

3) 为开发板编译NuttX:

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$ cd ../..
$ cd nuttx/tools
$ ./configure.sh stm32f103-minimum/nsh
$ cd ..
$ make menuconfig

如果报错 kconfig-mconf: error while loading shared libraries: libkconfig-parser-3.12.0.so: cannot open shared object file: No such file or directory

请把 /usr/local/lib 追加到 /etc/ld.so.conf文件

进入 “Build Setup” 菜单并且确认”Build Host Platform”定义为”Linux”
进入 “System Type” -> “Toolchain Selection” 确认值为 (X) Generic GNU EABI toolchain under Linux

选择EXIT并保存

现在可以编译了

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$ make

编译完成将打印

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make[2]: Leaving directory '/tmp/NuttX/nuttx/configs/stm32f103-minimum/src'
LD: nuttx
make[1]: Leaving directory '/tmp/NuttX/nuttx/arch/arm/src'
CP: nuttx.bin

往开发板烧写nuttx.bin
如图所示, 将数据线和下载器连接到开发板上

创建如下内容的配置文件openocd_stm32f1.cfg

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# Using stlink as SWD programmer
source [find interface/stlink-v2.cfg]
# SWD as transport
transport select hla_swd
# Use STM32F103 target
set WORKAREASIZE 0x4000
source [find target/stm32f1x.cfg]

执行OpenOCD

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$ sudo openocd -f openocd_stm32f1.cfg
Open On-Chip Debugger 0.10.0-dev-00300-g89bf96f-dirty (2016-05-20-17:42)
Licensed under GNU GPL v2
adapter speed: 1000 kHz
adapter_nsrst_delay: 100
none separate
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 v17 API v2 SWIM v4 VID 0x0483 PID 0x3748
Info : using stlink api v2
Info : Target voltage: 3.297181
Info : stm32f1x.cpu: hardware has 6 breakpoints, 4 watchpoints

在新的终端窗口执行

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$ telnet 127.0.0.1 4444
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
Open On-Chip Debugger
>
> reset halt
stm32f1x.cpu: target state: halted
target halted due to debug-request, current mode: Thread 
xPSR: 0x01000000 pc: 0x080003ac msp: 0x20000730
> flash write_image erase nuttx.bin 0x08000000
auto erase enabled
device id = 0x20036410
ignoring flash probed value, using configured bank size
flash size = 128kbytes
stm32f1x.cpu: target state: halted
target halted due to breakpoint, current mode: Thread 
xPSR: 0x61000000 pc: 0x2000003a msp: 0x20000730
wrote 40960 bytes from file nuttx.bin in 2.384699s (16.774 KiB/s)
>

最后，通过USB-串口连接开发板

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-------------------------------
|USB/Serial | STM32F103 Board |
-------------------------------
|   RXD     |       A9        |
|   TXD     |      A10        |
|   GND     |       G         |
-------------------------------

用minicom/picocom连接/dev/ttyUSBx以获取Nuttx终端, 连接参数为”115200 8n1 “
当按下开发板上重置按钮后，将获得nuttx终端

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NuttShell (NSH)
nsh>