MCU：STM32F407
環(huán)境：VSCode + PlatformIO IDE + STM32CubeF4(v1.5.2)
編譯器：7.2.1 20170904 (release) [ARM/embedded-7-branch revision 255204]
PlatformIO Core: version 5.1.1

STM32F4 Core Feature Description

問題描述

由于用的是STM32F4平臺，在ST產(chǎn)品線中定位為高性能計算產(chǎn)品，帶有FPU和DSP指令集，這不用來做數(shù)字信號處理屬實浪費，剛好近期工作需求要用到FFT或者FIR，所以，萬事俱備，開搞！！

1. DSP庫在哪？文檔？
看了一下PlatformIO自帶的STM32CubeF4庫，為了節(jié)約服務(wù)器帶寬和用戶下載時間，所以包很精簡，可是...這用起來很不方便呀，沒有文檔怎么寫代碼？

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于是去官網(wǎng)下了一個標準版本，1.6.1最新版，帶了文檔。然而后來才發(fā)現(xiàn)，原來CMSIS文檔是有在線版的：>>> CMSIS DSP Software Library <<<

官網(wǎng)：STMicroelectronics/STM32CubeF4: STM32Cube MCU Full Package for the STM32F4 series - Github

CMSIS文檔

2. 編譯Demo
按理說三分鐘出demo的事，結(jié)果一開始情況就不太妙...首先找到自帶例程（為了要例程還是得下完整庫）。拿一個FIR的例子開刀：

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復(fù)制進自己的項目，該函數(shù)名，燒錄運行？運行效果：

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！！直接復(fù)制進來用會 遇到成噸報錯轟炸！！
觀察日志會發(fā)現(xiàn)基本全是CMSIS庫中的變量缺失錯誤，以及類型缺失錯誤。定位錯誤可以發(fā)現(xiàn)：

image.png

類型錯誤很好解決，直接導(dǎo)入HAL的總?cè)肟?h文件#include （加到math_helper.h頂部）。
參考：#error 'Compiler generates FPU instructions for a device without an FPU (check __FPU_PRESENT)'

3. arm_math.h:932:41: error: redefinition of '__SMLALD'
編譯過后，錯誤少了一大筐：

但依然會有類似這種錯誤：

C:UsersJOY.platformiopackagesframework-stm32cubef4DriversCMSISInclude/cmsis_gcc.h:1652:31: note: previous definition of '__SHADD16' was here 1652 | __STATIC_FORCEINLINE uint32_t __SHADD16(uint32_t op1, uint32_t op2)

      |                               ^~~~~~~~~In file included from libarm_fir_example_f32math_helper.h:45,

                 from libarm_fir_example_f32arm_fir_example_f32.c:125:C:UsersJOY.platformiopackagesframework-stm32cubef4DriversCMSISDSPInclude/arm_math.h:932:41: error: redefinition of '__SMLALD'

  932 |   CMSIS_INLINE __STATIC_INLINE uint64_t __SMLALD(

      |                                         ^~~~~~~~In file included from C:UsersJOY.platformiopackagesframework-stm32cubef4DriversCMSISInclude/cmsis_compiler.h:48,

                 from C:UsersJOY.platformiopackagesframework-stm32cubef4DriversCMSISInclude/core_cm4.h:162,

                 from C:UsersJOY.platformiopackagesframework-stm32cubef4DriversCMSISDeviceSTSTM32F4xxInclude/stm32f407xx.h:167,

                 from C:UsersJOY.platformiopackagesframework-stm32cubef4DriversCMSISDeviceSTSTM32F4xxInclude/stm32f4xx.h:133,

                 from C:UsersJOY.platformiopackagesframework-stm32cubef4DriversSTM32F4xx_HAL_DriverInc/stm32f4xx_hal_def.h:30,

                 from C:UsersJOY.platformiopackagesframework-stm32cubef4DriversSTM32F4xx_HAL_DriverInc/stm32f4xx_hal_rcc.h:29,

                 from C:UsersJOY.platformiopackagesframework-stm32cubef4DriversSTM32F4xx_HAL_DriverInc/stm32f4xx_hal_conf.h:281,

                 from C:UsersJOY.platformiopackagesframework-stm32cubef4DriversSTM32F4xx_HAL_DriverInc/stm32f4xx_hal.h:30,

                 from libarm_fir_example_f32math_helper.h:44,

                 from libarm_fir_example_f32arm_fir_example_f32.c:125:

繼續(xù)定位，發(fā)現(xiàn)缺失的變量在cmsis_iccarm.h文件有定義：

根據(jù)導(dǎo)入鏈，查看arm_math.h文件，發(fā)現(xiàn)里面有這樣一行宏定義，在VSCode中顯示為灰色：

#if defined(ARM_MATH_CM7)

  #include 'core_cm7.h'

  #define ARM_MATH_DSP#elif defined (ARM_MATH_CM4)

  #include 'core_cm4.h'

  #define ARM_MATH_DSP

這個解決辦法就很明確了，直接在頂層include 文件添加一個宏定義，對應(yīng)到自己的MCU平臺即可。由于STM32F4系列對應(yīng)于Cortex-M4架構(gòu)，所以這里定義一個ARM_MATH_CM4。

math_helper.h頭部：

#define ARM_MATH_CM4#include #include 'arm_math.h'

編譯：

4. arm_fir_example_f32.c:202: undefined reference to `arm_fir_f32'

Archiving .piobuildblack_f407zgliba89libarm_fir_example_f32.aArchiving .piobuildblack_f407zglibFrameworkCMSISDevice.aLinking .piobuildblack_f407zgfirmware.elf

c:/users/joy/.platformio/packages/toolchain-gccarmnoneeabi@2.00000.0/bin/../lib/gcc/arm-none-eabi/10.2.1/../../../../arm-none-eabi/bin/ld.exe: .piobuildblack_f407zgliba89libarm_fir_example_f32.a(arm_fir_example_f32.o): in function `fir_test':C:DocumentsPlatformIOProjectsSTM32F4_ADC_Sampling_v2/libarm_fir_example_f32/arm_fir_example_f32.c:194: undefined reference to `arm_fir_init_f32'

c:/users/joy/.platformio/packages/toolchain-gccarmnoneeabi@2.00000.0/bin/../lib/gcc/arm-none-eabi/10.2.1/../../../../arm-none-eabi/bin/ld.exe: C:DocumentsPlatformIOProjectsSTM32F4_ADC_Sampling_v2/libarm_fir_example_f32/arm_fir_example_f32.c:202: undefined reference to `arm_fir_f32'

collect2.exe: error: ld returned 1 exit status*** [.piobuildblack_f407zgfirmware.elf] Error 1

經(jīng)典的符號未定義問題，而且是在link階段出現(xiàn)的，說明DSP庫沒有正確鏈接上。也就是說這個庫對于編譯器來說是不知道在哪個位置的，需要自己添加上。

定位庫文件：

用的GCC編譯器，進去發(fā)現(xiàn)問題來了，選哪個呢？

搜索了解后知道，l是指little endian，f是指帶有硬件除法器，那么沒有疑問，用帶lf的那個，也就是libarm_cortexM4lf_math.a。

5. 導(dǎo)入DSP靜態(tài)庫

問題又來了，怎么導(dǎo)入到PIO呢？

打開platformio.ini文件，在環(huán)境中添加一行：

build_flags = 

    -LC:UsersJOY.platformiopackagesframework-stm32cubef4DriversCMSISLibGCC    -larm_cortexM4lf_math

第N次編譯，結(jié)果：

c:/users/joy/.platformio/packages/toolchain-gccarmnoneeabi@2.00000.0/bin/../lib/gcc/arm-none-eabi/10.2.1/../../../../arm-none-eabi/bin/ld.exe: error: C:UsersJOY.platformiopackagesframework-stm32cubef4DriversCMSISLibGCClibarm_cortexM4lf_math.a(arm_fir_init_q15.o) uses VFP register arguments, .piobuildblack_f407zgfirmware.elf does not

c:/users/joy/.platformio/packages/toolchain-gccarmnoneeabi@2.00000.0/bin/../lib/gcc/arm-none-eabi/10.2.1/../../../../arm-none-eabi/bin/ld.exe: failed to merge target specific data of file C:UsersJOY.platformiopackagesframework-stm32cubef4DriversCMSISLibGCClibarm_cortexM4lf_math.a(arm_fir_init_q15.o)c:/users/joy/.platformio/packages/toolchain-gccarmnoneeabi@2.00000.0/bin/../lib/gcc/arm-none-eabi/10.2.1/../../../../arm-none-eabi/bin/ld.exe: error: C:UsersJOY.platformiopackagesframework-stm32cubef4DriversCMSISLibGCClibarm_cortexM4lf_math.a(arm_fir_init_f32.o) uses VFP register arguments, .piobuildblack_f407zgfirmware.elf does not

c:/users/joy/.platformio/packages/toolchain-gccarmnoneeabi@2.00000.0/bin/../lib/gcc/arm-none-eabi/10.2.1/../../../../arm-none-eabi/bin/ld.exe: failed to merge target specific data of file C:UsersJOY.platformiopackagesframework-stm32cubef4DriversCMSISLibGCClibarm_cortexM4lf_math.a(arm_fir_init_f32.o)c:/users/joy/.platformio/packages/toolchain-gccarmnoneeabi@2.00000.0/bin/../lib/gcc/arm-none-eabi/10.2.1/../../../../arm-none-eabi/bin/ld.exe: error: C:UsersJOY.platformiopackagesframework-stm32cubef4DriversCMSISLibGCClibarm_cortexM4lf_math.a(arm_fir_f32.o) uses VFP register arguments, .piobuildblack_f407zgfirmware.elf does not

c:/users/joy/.platformio/packages/toolchain-gccarmnoneeabi@2.00000.0/bin/../lib/gcc/arm-none-eabi/10.2.1/../../../../arm-none-eabi/bin/ld.exe: failed to merge target specific data of file C:UsersJOY.platformiopackagesframework-stm32cubef4DriversCMSISLibGCClibarm_cortexM4lf_math.a(arm_fir_f32.o)collect2.exe: error: ld returned 1 exit status*** [.piobuildblack_f407zgfirmware.elf] Error 1

6. 啟用編譯器（MCU）浮點數(shù)擴展

這里理一下思路：我們要用F4的浮點數(shù)運算能力，但是浮點數(shù)運算需要用到VFP指令和寄存器，但是libarm_cortexM4lf_math.a使用了VFP寄存器，而.piobuildblack_f407zgfirmware.elf沒有使用....

這個問題的解讀就是，生成一個可執(zhí)行文件elf時，其所有的中間對象*.o都要是同樣的編譯條件，至少對于VFP指令集的設(shè)置應(yīng)該是相同的。但是目前的ELF文件沒有啟用這個選項。

那么問題就簡單了，啟用一下不就可以了，而方式應(yīng)該就是通過對編譯器傳參，在platformIO中就對應(yīng)于，設(shè)置platformio.ini文件中的build_flags。

查過以上資料后，發(fā)現(xiàn)我應(yīng)該這么設(shè)置：

[env:black_f407zg]build_type = debug

platform = ststm32

board = black_f407zg

framework = stm32cube

upload_protocol = stlink

debug_tool = stlink

monitor_speed = 115200build_flags = 

    -LC:UsersJOY.platformiopackagesframework-stm32cubef4DriversCMSISLibARM    -larm_cortexM4lf_math    -mthumb -mcpu=cortex-m4 -march=armv7e-m -mfloat-abi=hard -mfpu=fpv4-sp-d16

也就是添加一行5個flag

-mthumb -mcpu=cortex-m4 -march=armv7e-m -mfloat-abi=hard -mfpu=fpv4-sp-d16

使用過后，編譯結(jié)果：

c:/users/joy/.platformio/packages/toolchain-gccarmnoneeabi@2.00000.0/bin/../lib/gcc/arm-none-eabi/10.2.1/../../../../arm-none-eabi/bin/ld.exe: failed to merge target specific data of file .piobuildblack_f407zgFrameworkHALDriverSrcstm32f4xx_ll_fsmc.o

c:/users/joy/.platformio/packages/toolchain-gccarmnoneeabi@2.00000.0/bin/../lib/gcc/arm-none-eabi/10.2.1/../../../../arm-none-eabi/bin/ld.exe: error: .piobuildblack_f407zgsrcsystem_stm32f4xx.o uses VFP register arguments, .piobuildblack_f407zgfirmware.elf does not

c:/users/joy/.platformio/packages/toolchain-gccarmnoneeabi@2.00000.0/bin/../lib/gcc/arm-none-eabi/10.2.1/../../../../arm-none-eabi/bin/ld.exe: failed to merge target specific data of file .piobuildblack_f407zgsrcsystem_stm32f4xx.o

c:/users/joy/.platformio/packages/toolchain-gccarmnoneeabi@2.00000.0/bin/../lib/gcc/arm-none-eabi/10.2.1/../../../../arm-none-eabi/bin/ld.exe: error: .piobuildblack_f407zgliba89libarm_fir_example_f32.a(arm_fir_example_f32.o) uses VFP register arguments, .piobuildblack_f407zgfirmware.elf does not...c:/users/joy/.platformio/packages/toolchain-gccarmnoneeabi@2.00000.0/bin/../lib/gcc/arm-none-eabi/10.2.1/../../../../arm-none-eabi/bin/ld.exe: failed to merge target specific data of file .piobuildblack_f407zgliba89libarm_fir_example_f32.a(arm_fir_example_f32.o)c:/users/joy/.platformio/packages/toolchain-gccarmnoneeabi@2.00000.0/bin/../lib/gcc/arm-none-eabi/10.2.1/../../../../arm-none-eabi/bin/ld.exe: error: .piobuildblack_f407zgliba89libarm_fir_example_f32.a(fft.o) uses VFP register arguments, .piobuildblack_f407zgfirmware.elf does not

c:/users/joy/.platformio/packages/toolchain-gccarmnoneeabi@2.00000.0/bin/../lib/gcc/arm-none-eabi/10.2.1/../../../../arm-none-eabi/bin/ld.exe: failed to merge target specific data of file .piobuildblack_f407zgliba89libarm_fir_example_f32.a(fft.o)c:/users/joy/.platformio/packages/toolchain-gccarmnoneeabi@2.00000.0/bin/../lib/gcc/arm-none-eabi/10.2.1/../../../../arm-none-eabi/bin/ld.exe: error: .piobuildblack_f407zgliba89libarm_fir_example_f32.a(math_helper.o) uses VFP register arguments, .piobuildblack_f407zgfirmware.elf does not