stm32f4xx使用FPU方法及简单测试
stm32 浮点数乘除法
stm32 浮点数乘除法在STM32 微控制器中，浮点数乘法和除法可以通过使用浮点数处理单元（Floating Point Unit, FPU）中的相应指令来实现。
下面是两种常见的方法：1. 使用标准的C 语言库函数：- 浮点数乘法：可以使用`<math.h>` 头文件中的`float` 或`double` 类型的乘法函数，例如`float result = a * b;`。
- 浮点数除法：同样可以使用`<math.h>` 头文件中的乘法函数，例如`float result = a / b;`。
2. 使用浮点数处理单元（FPU）指令：- 浮点数乘法：在使用浮点数乘法时，可以直接使用FPU 中的指令进行乘法操作。
具体的指令取决于STM32 微控制器型号和所使用的编译器。
例如，对于STM32F4 系列的微控制器，可以使用以下指令实现浮点数乘法：```float result;__asm("VMLA.F32 %0, %1, %2" : "=t"(result) : "t"(a), "t"(b));```- 浮点数除法：同样可以使用FPU 中的指令进行除法操作。
对于STM32F4 系列的微控制器，可以使用以下指令实现浮点数除法：```float result;__asm("VDIV.F32 %0, %1, %2" : "=t"(result) : "t"(a), "t"(b));```请注意，具体的指令和语法可能会根据不同的STM32 微控制器型号和使用的编译器而有所变化。
建议参考相关的微控制器文档和编译器手册以获取详细的信息和准确的指令形式。
STM32F4xx系列IAP之U盘版
STM32F4xx系列IAP之U盘版本文是STM32F4xx系列U盘IAP的详细说明文档，并采用理论结合例程的全新方式向读者讲述如何使用本例程进行IAP操作，凡是STM32F4xx系列单片机（带USBOTG接口）并满足USB硬件连接条件的系统都可以使用本例程，本例程具有丰富的可拓展性，例如可以改变BOOT区的大小，可以屏幕打印IAP输出信息，可以选择BOOT程序的启动方式，可以自启动，也可以由事件启动比如按键，等。
本文主要对以下内容进行讲解：1.STM32IAP技术简介2.STM32F4xx系列U盘IAP方案3.U盘IAP程序例程详细讲解4.使用该BOOT可能遇到的问题及解决办法5.程序拓展1.STM32IAP技术简介IAP，全称是“In-Application-Programming”，中文解释为“在程序中编程”。
IAP是一种对通过微控制器的对外接口实现自身程序更新的技术。
在STM32微控制器上实现IAP程序之前首先要回顾一下STM32的内部闪存组织架构和其启动过程。
STM32的内部闪存地址起始于0x8000000，一般情况下，程序文件就从此地址开始写入。
此外STM32是基于Cortex内核的微控制器，其内部通过一张“中断向量表”来响应中断，程序启动后，将首先从“中断向量表”取出复位中断向量执行复位中断程序完成启动。
而这张“中断向量表”的起始地址是0x8000004，当中断来临，STM32的内部硬件机制亦会自动将PC 指针定位到“中断向量表”处，并根据中断源取出对应的中断向量执行中断服务程序。
最后还需要知道关键的一点，通过修改STM32工程的链接脚本可以修改程序文件写入闪存的起始地址。
2.STM32F4xx系列U盘IAP方案要在STM32上实现IAP功能首先需要将FLASH分为两个区域，一部分叫做BOOT区，它的起始地址这0x08000000，它的作用是将需要升级的程序写入特定的区域并实现跳转，另一部分叫用户程序区，存储用户的应用程序，它的起始地址要根据BOOT区的程序大小而定。
教你如何使用STM32F4的DSP库
教你如何使用STM32F4的DSP库
我们平常所使用的CPU为定点CPU，意思是进行整点数值运算的CPU。
当遇到形如1.1+1.1的浮点数运算时，定点CPU就遇到大难题了。
对
于32位单片机，利用Q化处理能发挥他本身的性能，但是精度和速度仍然
不会提高很多。
现在设计出了一个新的CPU，叫做FPU，这个芯片专门处理浮点数的运算，这样处理器就将整点数和浮点数分开来处理，整点数交由定点CPU处理而浮点数交由FPU处理。
我们见到过TI的DSP，还有STM32F4系列的带有DSP 功能的微控制器。
前者笔者没有用过，不作评论，而后者如果需要用到FPU
的浮点运算功能，必须要进行一些必要的设置。
首先，由于浮点运算在FPU中进行，所以首先应该使能FPU运行。
在system_init()中，定义__FPU_PRESENT和__FPU_USED
/* FPU settings------------------------------------------------------------*/
#if (__FPU_PRESENT == 1)&& (__FPU_USED == 1)
SCB->CPACR |= ((3UL#endif
这样就使能了FPU。
实验46_2 FPU测试(Julia分形)实验_关闭硬件FPU
#include "sys.h"#include "delay.h"#include "usart.h"#include "led.h"#include "key.h"#include "lcd.h"#include "timer.h"//46_2,本版本为关闭硬件FPU版本.//FPU模式提示#if __FPU_USED==1#define SCORE_FPU_MODE "FPU On"#else#define SCORE_FPU_MODE "FPU Off"#endif#define ITERATION 128 //迭代次数#define REAL_CONSTANT 0.285f //实部常量#define IMG_CONSTANT 0.01f //虚部常量//颜色表u16 color_map[ITERATION];//缩放因子列表const u16 zoom_ratio[] ={120, 110, 100, 150, 200, 275, 350, 450,600, 800, 1000, 1200, 1500, 2000, 1500,1200, 1000, 800, 600, 450, 350, 275, 200,150, 100, 110,};//初始化颜色表//clut:颜色表指针void InitCLUT(u16 * clut){u32 i=0x00;u16 red=0,green=0,blue=0;for(i=0;i<ITERATION;i++)//产生颜色表{//产生RGB颜色值red=(i*8*256/ITERATION)%256;green=(i*6*256/ITERATION)%256;blue=(i*4*256 /ITERATION)%256;//将RGB888,转换为RGB565red=red>>3;red=red<<11;green=green>>2;green=green<<5;blue=blue>>3;clut[i]=red+green+blue;}}//产生Julia分形图形//size_x,size_y:屏幕x,y方向的尺寸//offset_x,offset_y:屏幕x,y方向的偏移//zoom:缩放因子void GenerateJulia_fpu(u16 size_x,u16 size_y,u16 offset_x,u16 offset_y,u16 zoom) {u8 i;u16 x,y;float tmp1,tmp2;float num_real,num_img;float radius;for(y=0;y<size_y;y++){for(x=0;x<size_x;x++){num_real=y-offset_y;num_real=num_real/zoom;num_img=x-offset_x;num_img=num_img/zoom;i=0;radius=0;while((i<ITERATION-1)&&(radius<4)){tmp1=num_real*num_real;tmp2=num_img*num_img;num_img=2*num_real*num_img+IMG_CONSTANT;num_real=tmp1-tmp2+REAL_CONSTANT;radius=tmp1+tmp2;i++;}LCD->LCD_RAM=color_map[i];//绘制到屏幕}}}u8 timeout;int main(void){u8 key;u8 i=0;u8 autorun=0;float time;u8 buf[50];Stm32_Clock_Init(336,8,2,7);//设置时钟,168Mhzdelay_init(168); //延时初始化uart_init(84,115200); //初始化串口波特率为115200LED_Init(); //初始化LEDKEY_Init(); //初始化按键LCD_Init(); //初始化LCDTIM3_Int_Init(65535,8400-1);//10Khz计数频率,最大计时6.5秒超出POINT_COLOR=RED;LCD_ShowString(30,50,200,16,16,"Explorer STM32F4");LCD_ShowString(30,70,200,16,16,"FPU TEST");LCD_ShowString(30,90,200,16,16,"ATOM@ALIENTEK");LCD_ShowString(30,110,200,16,16,"2014/7/2");LCD_ShowString(30,130,200,16,16,"KEY0:+ KEY2:-"); //显示提示信息LCD_ShowString(30,150,200,16,16,"KEY_UP:AUTO/MANUL"); //显示提示信息delay_ms(1200);POINT_COLOR=BLUE; //设置字体为蓝色InitCLUT(color_map);//初始化颜色表while(1){key=KEY_Scan(0);switch(key){case KEY0_PRES:i++;if(i>sizeof(zoom_ratio)/2-1)i=0;//限制范围break;case KEY2_PRES:if(i)i--;else i=sizeof(zoom_ratio)/2-1;break;case WKUP_PRES:autorun=!autorun; //自动/手动break;}if(autorun==1)//自动时,自动设置缩放因子{i++;if(i>sizeof(zoom_ratio)/2-1)i=0;//限制范围}LCD_Set_Window(0,0,lcddev.width,lcddev.height);//设置窗口LCD_WriteRAM_Prepare();TIM3->CNT=0;//重设TIM3定时器的计数器值timeout=0;GenerateJulia_fpu(lcddev.width,lcddev.height,lcddev.width/2,lcddev.height/2,zoom_ratio[i]);time=TIM3->CNT+(u32)timeout*65536;sprintf((char*)buf,"%s: zoom:%d runtime:%0.1fms\r\n",SCORE_FPU_MODE,zoom_ratio[i],time/10);LCD_ShowString(5,lcddev.height-5-12,lcddev.width-5,12,12,buf);//显示当前运行情况printf("%s",buf);//输出到串口LED0=!LED0;}}。
STM32F4的FPU性能的设置及要点
STM32F4的FPU性能的设置及要点除了网上的教程外，还要特别注意，当运算中有浮点的数字时要把，数字后面加上一个f。
例如表达式中有4.321参与运算。
当你不在4.321后加f时，stm32F405的片子不知道把他当做单精度float用FPU来运算，，默认可能是当做double来运算（我不确定），运算速度还是很慢。
切记所有浮点数字后面加上f，，，，有时候keil会提示warning：#1035-D：single-precision operand implicitly converted to double-precision 这句话的意思就是单精度运算隐式转换成了双精度运算了。
这个时候就要在单精度数字后面加个fkeilmdk的设置中完整的define是USE_STDPERIPH_DRIVER，STM32F4XX，__FPU_PRESENT=1，__FPU_USED =1，ARM_MATH_CM4，__CC_ARM要在MDK中有个选项设置usr FPUSTM32F4之FPU性能的充分发挥-设置要点浮点运算一直是定点CPU的难题，比如一个简单的1.1+1.1，定点CPU必须要按照IEEE-754标准的算法来完成运算，对于8位单片机来说已经完全是噩梦，对32为单片机来说也不会有多大改善。
虽然将浮点数进行Q化处理能充分发挥32位单片机的运算性能，但是精度受到限制而不会太高。
对于有FPU（浮点运算单元）的单片机或者CPU来说，浮点加法只是几条指令的事情。
现在又FPU或者硬件浮点运算能力的主要有高端DSP（比如TI F28335/C6000/DM6XX/OMAP等），通用CPU（X87数学协处理器）和高级的ARM+DSP 处理器等。
STM32-F4属于Cortex-M4F构架，这和M0、M3的最大不同就是多了一个F-float，即支持浮点指令集，因此在处理数学运算时能比M0/M3高出数十倍甚至上百倍的性能，但是要充分发挥FPU的数学性能，还需要一些小小的设置：1.编译控制选项：虽然STM32F4XX固件库的例程之system_stm32f4XXX.c文件中添加了对应的代码，但给用户评估使用的STM32F4-Discovery例程中却没有，因此MDK4.23编。
STM32F4 DSP库学习笔记5-复数FFT的实现方法
STM32F4 DSP库学习笔记5-复数FFT的实现方法我们会用了ST官方的汇编FFT库，那些库函数在没有带FPU浮点运算的32芯片上也可以用的不错。
然后今天我们就用一下F4的DSP库。
在该目录下包含了图中所示的源文件复数FFT函数支持三种数据类型，分别是浮点，Q31和Q15，待会就拿浮点数来做例子。
先介绍下函数：void arm_cfft_f32(const arm_cfft_instance_f32 * S,float32_t * p1,uint8_t ifftFlag,uint8_t bitReverseFlag);arm_cfft_instance_f32 * S是一个结构体指针这个结构体包含FFT运算的旋转因子和位反转表，就相当于一个常量，我们不用去管它。
float32_t * p1，是输入复数数组的地址，长度应该是运算点数的两倍，注意的是输入和输出共用一块缓存uint8_t ifftFlag,是运算的正反标志ifftFlag=1是反变换。
ifftFlag=0是正变换uint8_t bitReverseFlag，是flag that enables (bitReverseFlag=1) or disables (bitReverseFlag =0) bit好，然后就只要这一句话就可以计算复数的FFT正变换arm_cfft_f32(&arm_cfft_sR_f32_len1024,testInput,0, 1);计算出结果后，用下面语句就可以求出幅值了；arm_cmplx_mag_f32(testInput, testOutput, 1024);关于arm_cmplx_mag_f32(testInput, testOutput, 1024)，它的原型是：void arm_cmplx_mag_f32(float32_t * pSrc,float32_t * pDst,uint32_t numSamples);这个函数是求复数的模值float32_t * pSrc,是输入数组地址float32_t * pDst,是输出数组地址uint32_t numSamples是运算点数当然上面语句中testInput数组的长度是testOutput数组的两倍。
STM32CubeF4例程使用说明
STM32CubeF4例程使⽤说明February 2014DocID025922 Rev 11/22UM1730User manualGetting started with STM32CubeF4 firmware packagefor STM32F4xx seriesIntroductionThe STM32Cube ? initiative was originated by STMicroelectronics to ease developers life by reducing development efforts, time and cost. STM32Cube ? covers the STM32 portfolio.STM32Cube Version 1.x includes:The STM32CubeMX, a graphical software configuration tool that allows to generate C initialization code using graphical wizards ? A comprehensive embedded software platform, delivered per series (such as STM32CubeF4 for STM32F4 series)–The STM32Cube HAL, an STM32 abstraction layer embedded software, ensuring maximized portability across the STM32 portfolio –A consistent set of middleware components such as RTOS, USB, TCP/IP and graphics –All embedded software utilities coming with a full set of examples.This user manual describes how to get started with the STM32CubeF4 firmware package. Section 1 describes the main features of STM32CubeF4 firmware, part of theSTM32Cube ? initiative.Section 2 and Section 3 provide an overview of the STM32CubeF4 architecture andfirmware package structure./doc/51b6f178cfc789eb162dc80c.htmlContents UM1730Contents1STM32CubeF4 main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2STM32CubeF4 architecture overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 63STM32CubeF4 firmware package overview . . . . . . . . . . . . . . . . . . . . . . 93.1Supported STM32F4 devices and hardware . . . . . . . . . . . . . . . . . . . . . . . 93.2Firmware package overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104Getting started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154.1How to run your first example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154.2How to develop your own application . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164.3Using STM32CubeMX for generating the initialization C code . . . . . . . . 174.4How to get STM32CubeF4 release updates . . . . . . . . . . . . . . . . . . . . . . 184.4.1How to install and run the STM32CubeUpdater program . . . . . . . . . . . 18 5FAQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 6Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212/22DocID025922 Rev 1UM1730List of tables List of tablesTable 1.Macros for STM32F4 series. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Table 2.Evaluation and Discovery boards for STM32F4 series. . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Table 3.Number of examples available for each board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Table 4.Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21DocID025922 Rev 13/22List of figures UM1730 List of figuresFigure 1.STM32CubeF4 firmware components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 2.STM32CubeF4 firmware architecture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Figure 3.STM32CubeF4 firmware package structure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Figure 4.STM32CubeF4 examples overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 4/22DocID025922 Rev 1DocID025922 Rev 15/22UM1730STM32CubeF4 main features 1 STM32CubeF4 main featuresSTM32CubeF4 gathers together, in a single package, all the generic embedded softwarecomponents required to develop an application on STM32F4 microcontrollers. In line withthe STM32Cube initiative, this set of components is highly portable, not only within theSTM32F4 series but also to other STM32 series.STM32CubeF4 is fully compatible with STM32CubeMX code generator that allows the userto generate initialization code. The package includes a low level hardware abstraction layer(HAL) that covers the microcontroller hardware, together with an extensive set of examplesrunning on STMicroelectronics boards. The HAL is available in an open-source BSD licensefor user convenience.STM32CubeF4 package also contains a set of middleware components with thecorresponding examples. They come with very permissive license terms:Full USB Host and Device stack supporting many classes.–Host Classes: HID, MSC, CDC, Audio, MTP –Device Classes: HID, MSC, CDC, Audio, DFU ?STemWin, a professional graphical stack solution available in binary format and based on the emWin solution from ST's partner Segger ?CMSIS-RTOS implementation with FreeRTOS open source solution ?FAT File system based on open source FatFS solution ?TCP/IP stack based on open source LwIP solution ?SSL/TLS secure layer based on open source PolarSSLA demonstration implementing all these middleware components is also provided in theSTM32CubeF4 package.2 STM32CubeF4 architecture overviewThe STM32CubeF4 firmware solution is built around three independent levels that caneasily interact with each other as described in the Figure 1 below:Level 0: This level is divided into three sub-layers:Board Support Package (BSP): this layer offers a set of APIs related to the hardware components on the hardware boards (Audio codec, I/O expander, Touchscreen, SRAMdriver, LCD drivers. etc…) and composed of two parts:–Component: is the driver related to the external device on the board and notrelated to the STM32, the component driver provides specific APIs to the BSPdriver’s external components and can be ported to any board.–BSP driver: it enables the component driver to be linked to a specific board and provides a set of user-friendly APIs. The API naming rule isBSP_FUNCT_Action(): ex. BSP_LED_Init(),BSP_LED_On()It's based on a modular architecture that allows it to be ported easily to any hardwareby just implementing the low level routines.Hardware Abstraction Layer (HAL): this layer provides the low level drivers and theand stacks). It provides generic, multi instance and function-oriented APIs which allowto offload the user application implementation by providing ready-to-use processes. Forexample, for the communication peripherals (I2S, UART…) it provides APIs allowing to6/22DocID025922 Rev 1initialize and configure the peripheral, manage data transfer based on polling, interrupt or DMA process, and manage communication errors that may raise duringcommunication. The HAL Drivers APIs are split in two categories, generic APIs which provides common and generic functions to all the STM32 series and extension APIs which provides specific and customized functions for a specific family or a specific part number.Basic peripheral usage examples: this layer contains examples of basic operation of the STM32F4 peripherals using only the HAL and BSP resources.Level 1: This level is divided into two sub-layers:Middleware components: a set of Libraries covering USB Host and Device Libraries, STemWin, FreeRTOS, FatFS, LwIP, and PolarSSL. Horizontal interactions between the components of this layer are done directly by calling the feature APIs while the vertical interaction with the low level drivers is done through specific callbacks and staticmacros implemented in the library system call interface. For example, the FatFsimplements the disk I/O driver to access microSD drive or the USB Mass StorageClass.The main features of each Middleware component are as follows:USB Host and Device Libraries–Several USB classes supported (Mass-Storage, HID, CDC, DFU, AUDIO, MTP)–Supports multi packet transfer features: allows sending big amounts of data without splitting them into max packet size transfers.–Uses configuration files to change the core and the library configuration without changing the library code (Read Only).–Includes 32-bit aligned data structures to handle DMA-based transfer in High-speed modes.–Supports multi USB OTG core instances from user level through configuration file (allows operation with more than one USB host/device peripheral).–RTOS and Standalone operation–The link with low-level driver is done through an abstraction layer using the configuration file to avoid any dependency between the Library and the low-levelsolution–Optimized display drivers–Software tools for code generation and bitmap editing (STemWin Builder…)FreeRTOS–Open source standard–CMSIS compatibility layer–Tickless operation during low-power mode–Integration with all STM32Cube Middleware modulesDocID025922 Rev 17/22FAT File system–FATFS FAT open source library–Long file name support–Dynamic multi-drive support–RTOS and standalone operation–Examples with microSD and USB host Mass-storage classLwIP TCP/IP stack–Open source standard–RTOS and standalone operationExamples based on the Middleware components: each Middleware component comes with one or more examples (called also Applications) showing how to use it.Integration examples that use several Middleware components are provided as well.Level 2: This level is composed of a single layer which is a global real-time and graphicaldemonstration based on the Middleware service layer, the low level abstraction layer andthe applications that make basic use of the peripherals for board-based functions.8/22DocID025922 Rev 1DocID025922 Rev 19/223STM32CubeF4 firmware package overview 3.1 Supported STM32F4 devices and hardwareSTM32Cube offers a highly portable Hardware Abstraction Layer (HAL) built around ageneric and modular architecture allowing the upper layers, Middleware and Application, toimplement its functions without in-depth knowledge of the MCU being used. This improvesthe library code re-usability and guarantees an easy portability from one device to another.The STM32CubeF4 offers full support for all STM32F4 Series devices. You only have todefine the right macro in stm32f4xx.h.Table 1 below lists which macro to define depending on the STM32F4 device you are using(this macro can also be defined in the compiler preprocessor).STM32CubeF4 features a rich set of examples and demonstrations at all levels making iteasy to understand and use any HAL driver and/or Middleware components. These Table 1. Macros for STM32F4 series Macro defined instm32f4xx.h STM32F4 devicesSTM32F405xx STM32F405RG, STM32F405VG and STM32F405ZGSTM32F415xx STM32F415RG, STM32F415VG and STM32F415ZGSTM32F407xx STM32F407VG, STM32F407VE, STM32F407ZG, STM32F407ZE,STM32F407IG and STM32F407IESTM32F417xx STM32F417VG, STM32F417VE, STM32F417ZG, STM32F417ZE,STM32F417IG and STM32F417IESTM32F427xx STM32F427VG, STM32F427VI, STM32F427ZG, STM32F427ZI,STM32F427IG and STM32F427IISTM32F437xx STM32F437VG, STM32F437VI, STM32F437ZG, STM32F437ZI,STM32F437IG and STM32F437IISTM32F429xx STM32F429VG, STM32F429VI, STM32F429ZG, STM32F429ZI,STM32F429BG, STM32F429BI, STM32F429NG, STM32F439NI,STM32F429IG and STM32F429IISTM32F439xx STM32F439VG, STM32F439VI, STM32F439ZG, STM32F439ZI,STM32F439BG, STM32F439BI, STM32F439NG, STM32F439NI,STM32F439IG and STM32F439IISTM32F401xC STM32F401CB, STM32F401CC, STM32F401RB, STM32F401RC,STM32F401VB and STM32F401VCSTM32F401xESTM32F401CD, STM32F401RD, STM32F401VD, STM32F401CE,STM32F401RE, STM32F401VEexamples can be run on any of the STMicroelectronics boards as listed in Table 2 below:Table 2. Evaluation and Discovery boards for STM32F4 seriesThe STM32CubeF4 firmware is able to run on any compatible hardware. This means youcan simply update the BSP drivers to port the provided examples to your own board, if it hasthe same hardware functions (LED, LCD display, pushbuttons...etc.).overview3.2 FirmwarepackageThe STM32CubeF4 firmware solution is provided in a single zip package with the structureshown in Figure 3 below.10/22DocID025922 Rev 1For each board, a set of examples are provided with preconfigured projects for EWARM, MDK-ARM and TrueSTUDIO toolchains.Figure 4 shows the project structure for the STM324xG-EVAL board. The structure is identical for other boards.The examples are classified depending on the STM32Cube level they apply to, and are named as follows: Examples in level 0 are called Examples, that use HAL drivers without any Middleware componentExamples in level 1 are called Applications, that provide typical use cases of each Middleware component Examples in level 2 are called Demonstration, that implement all the HAL, BSP and Middleware componentsA Template project is provided to allow you to quickly build any firmware application on agiven board.DocID025922 Rev 111/22All examples have the same structure,\Inc folder that contains all header files\Src folder for the sources code\EWARM, \MDK-ARM and \TrueSTUDIO folders contain the preconfigured project for each toolchain.readme.txt describing the example behavior and the environment required to make it work 12/22DocID025922 Rev 1Figure 4. STM32CubeF4 examples overviewDocID025922 Rev 113/22Table 3 provides the number of examples, applications and demonstrations available for each board.Table 3. Number of examples available for each boardBoard Examples Applications Demonstration STM324x9I_EVAL83561STM324xG_EVAL68521STM32F4-Discovery2241STM32F401-Discovery2041STM32F429I-Discovery2681STM32F4xx-Nucleo3NA NA14/22DocID025922 Rev 1UM1730Getting startedstarted4 Getting4.1 How to run your first exampleThis section explains how simple it is to run a first example with STM32CubeF4. As an illustration let's consider to run a simple LED toggling example running on the STM32F4-Discovery board:1.After downloading the STM32CubeF4 firmware package, unzip it into a directory of your choice, you just need to ensure that the package structure is not modified (as shown in Figure 3 above).2. Browse to \Projects\STM32F4-Discovery\Examples.3. Open \GPIO, then the \GPIO_EXTI folder.4. Open the project with your preferred toolchain.5. Rebuild all files and load your image into target memory.6. Run the example: each time you press User button 4, the LEDs will toggle (for more details, refer to the example readme file).You will get a quick overview of how to open, build and run an example with the supported toolchains.EWARM–Under the example folder, open the \EWARM subfolder–Open the Project.eww workspace(a)–Rebuild all files: Project->Rebuild all–Load project image: Project->Debug–Run program: Debug->Go(F5)MDK-ARM–Under the example folder, open the \MDK-ARM subfolder–Open the Project.uvproj workspace(a)–Rebuild all files: Project->Rebuild all target files–Load project image: Debug->Start/Stop Debug Session–Run program: Debug->Run (F5)TrueSTUDIO–Open the TrueSTUDIO toolchain–Click on File->Switch Workspace->Other and browse to the TrueSTUDIOworkspace directory–Click on File->Import, select General->'Existing Projects into Workspace' and then click “Next”.–Browse to the TrueSTUDIO workspace directory, select the project–Rebuild all project files: Select the project in the “Project explorer” window then click on Project->build project menu.–Run program: Run->Debug (F11)a.The workspace name may change from one example to anotherDocID025922 Rev 115/22Getting started UM17304.2 How to develop your own applicationThis section describes the required steps needed to create your own application usingSTM32CubeF4.1.Create your project: to create a new project you can either start from the Templateproject provided for each board under \Projects\\Templates or fromany available project under \Projects\\Examples orSTM32F4-Discovery).The Template project provides an empty main loop function, this is a good starting pointto allow you to get familiar with the project settings for STM32CubeF4. It has thefollowing characteristics:a) It contains sources of the HAL, CMSIS and BSP drivers which are the minimumrequired components to develop code for a given boardb) It contains the include paths for all the firmware componentsc) It defines the STM32F4 device supported, allowing to have the right configurationfor the CMSIS and HAL driversd) It provides ready-to-use user files preconfigured as follows:- HAL is initialized- SysTick ISR implemented for HAL_Delay() purpose- System clock is configured with the maximum frequency of the deviceNote:If you copy an existing project to another location, then you need to update the include paths.2. Add the necessary Middleware to your project (optional): available Middlewarestacks are: USB Host and Device Libraries, STemWin, FreeRTOS, FatFS, LwIP, andPolarSSL. To find out which source files you need to add to the project files list, refer tothe documentation provided for each Middleware, you can also have a look at theapplications available under \Projects\STM32xx_xxx\Applications\( refers to the Middleware stack, for example USB_Device) to get a betteridea of the source files to be added and the include paths.3. Configure the firmware components: the HAL and Middleware components offer a set of build time configuration options using macros declared with “#define” in a header file. A template configuration file is provided within each component, which you have to copy to the project folder (usually the configuration file is named xxx_conf_template.h. The word “_template” needs to be removed when copying it to the project folder). The configuration file provides enough information to know the effect of each configuration option. More detailed information is available in the documentation provided for each component.4. Start the HAL Library: after jumping to the main program, the application code needsUM1730Getting started5. Configure the system clock: the system clock configuration is done by calling these two APIsa) HAL_RCC_OscConfig(): configures the internal and/or external oscillators, PLL source and factors. You can choose to configure one oscillator or all oscillators.You can also skip the PLL configuration if there is no need to run the system athigh frequencyb) HAL_RCC_ClockConfig(): configures the system clock source, Flash latency and AHB and APB prescalers6. Develop your application process: at this stage, your system is ready and you can start developing your application code.a) The HAL provides intuitive and ready-to-use APIs for configuring the peripheral, and supports polling, interrupt and DMA programming models, to accommodateany application requirements. For more details on how to use each peripheral,refer to the rich examples set provided.b) If your application has some real-time constraints, you can find a large set of examples showing how to use FreeRTOS and integrate it with all Middlewarestacks provided in STM32CubeF4, it can be a good starting point for yourdevelopment.c) IMPORTANT NOTE: care must be taken when using HAL_Delay(). This functionprovides an accurate delay (in milliseconds) based on a variable incremented inSysTick ISR. This implies that if HAL_Dely() is called from a peripheral ISRprocess, then the SysTick interrupt must have the highest priority (numericallylower) than the peripheral interrupt. Otherwise the caller ISR process will beblocked. To change the SysTick interrupt priority, you have to use theHAL_NVIC_SetPriority() function.4.3 Using STM32CubeMX for generating the initialization C codeAnother alternative to Steps 1 to 5 described in Section 4.2 consists in using theSTM32CubeMX tool to easily generate code for the initialization of the system, theperipherals and middleware (Steps 1 to 5 above) through a step-by-step process:Selection of the STMicroelectronics STM32 microcontroller that matches the required set of peripherals. Configuration of each required embedded software thanks to a pinout-conflict solver, a clock-tree setting helper, a power consumption calculator, and an utility performingMCU peripheral configuration (GPIO, USART...) and middleware stacks (USB,TCP/IP...).Generation of the initialization C code based on the configuration selected. This code is ready to be used within several development environments. The user code is kept atthe next code generation.For more information, please refer to UM1718.DocID025922 Rev 117/22Getting started UM173018/22DocID025922 Rev 14.4 How to get STM32CubeF4 release updatesThe STM32CubeF4 firmware package comes with an updater utility: STM32CubeUpdater,also available as a menu within STM32CubeMX code generation tool.The updater solution detects new firmware releases and patches available from/doc/51b6f178cfc789eb162dc80c.html andproposes to download them to the user’s computer.4.4.1 How to install and run the STM32CubeUpdater programDouble-click SetupSTM32CubeUpdater.exe file to launch the installation.?Accept the license terms and follow the different installation steps.Upon successful installation, STM32CubeUpdater becomes available as an STMicroelectronics program under Program Files and is automatically launched.The STM32CubeUpdater icon appears in the system tray:Right-click the updater icon and select Updater Settings to configure the Updater connection and whether to performmanual or automatic checks (see STM32CubeMXUser guide - UM1718 section 3 - for more details on Updater configuration).UM1730FAQ 5 FAQWhat is the license scheme for the STM32CubeF4 firmware?The HAL is distributed under a non-restrictive BSD (Berkeley Software Distribution) license. The Middleware stacks made by ST (USB Host and Device Libraries, STemWin) come with a licensing model allowing easy reuse, provided it runs on an ST device.The Middleware based on well-known open-source solutions (FreeRTOS, FatFs, LwIP and PolarSSL) have user-friendly license terms. For more details, refer to the license agreement of each Middleware.What boards are supported by the STM32CubeF4 firmware package?The STM32CubeF4 firmware package provides BSP drivers and ready-to-use examples for the following STM32F4 boards: STM324x9I_EVAL, STM324xG_EVAL, STM32F4-Discovery, STM32F401-Discovery, STM32F429I-Discovery, STM32F4xx-Nucleo.Is there any link with Standard Peripheral Libraries?The STM32Cube HAL Layer is the replacement of the Standard Peripheral Library.The HAL APIs offer a higher abstraction level compared to the standard peripheral APIs. HAL focuses on peripheral common functionalities rather than hardware. The higher abstraction level allows to define a set of user friendly APIs that can be easily ported from one product to another.Customers currently using Standard Peripheral Libraries will be helped through Migration guides. Existing Standard Peripheral Libraries will be supported, but not recommended for new designs.Does the HAL take benefit from interrupts or DMA? How can this becontrolled?without interrupt generation).Are any examples provided with the ready-to-use toolset projects?Yes. STM32CubeF4 provides a rich set of examples and applications (140 forSTM324x9I_EVAL). They come with the preconfigured project of several toolsets: IAR, Keil and GCC.How are the product/peripheral specific features managed?The HAL offers extended APIs, i.e. specific functions as add-ons to the common API to support features available on some products/lines only.How can STM32CubeMX generate code based on embedded software?STM32CubeMX has a built-in knowledge of STM32 microcontrollers, including theirperipherals and software. This enables the tool to provide a graphical representation to the user and generate *.h/*.c files based on user configuration.DocID025922 Rev 119/22。
STM32CubeF4使用入门
UM1730STM32CubeF4使用入门山西大学电子信息工程系王晓峰Wangxiaofeng@引言STMCube是由意法半导体原创倡议，旨在通过减少开发负担，时间和费用来为开发者提供轻松的开发体验。
STMCube覆盖了STM32全系列。
STM32Cube版本1.x包括：1、STM32CubeMX，一个图形软件配置工具，允许通过图形化向导来生成C初始化代码。
2、一个广泛的嵌入式软件平台，按照产品系列提供（例如STM32CubeF4对应STM32F4系列）。
此平台包括STM32Cube HAL（一个STM32的硬件抽象层，确保STM32之间最大的可移植性），再加上配套的中间件（RTOS,USB,TCP/IP和图形）。
所有嵌入式软件组件都提供完整的例程。
本用户手册描述了如何开始使用STM32CubeF4固件包。
第一部分，描述了STM32CubeF4固件包的主要特性，STMCube的首创倡议。
第二部分和第三部分提供了一个STM32CubeF4架构概览和固件包结构。
1STM32CubeF4主要特性STM32CubeF4集合了所有开发STM32F4应用嵌入式软件组件。
依照STMCube倡议，这些组件具有高度的可移植性，不止在STM32F4系列中，也包括所有STM32系列。
STM32CubeF4高度兼容STM32CubeMX，STM32CubeMX允许用户生成初始化代码。
包内包括一个底层硬件抽象层（HAL），HAL覆盖了微控制器硬件，集成了广泛的例程，可运行在意法半导体的开发板上。
为了用户便利，硬件抽象层为开源BSD许可协议。
STM32CubeF4包含了一套中间件组件，带有对应的例程。
它们具有非常自由的许可证条款：1、CMSIS-RTOS贯彻了FreeRTOS的开源解决方案2、TCP/IP协议栈基于开源的LwIP解决方案3、FAT文件系统基于开源的FatFs解决方案，支持NAND闪存访问4、完整的USB主从设备协议栈支持。
stm32f407标准库keil 浮点运算
stm32f407标准库keil 浮点运算
在Keil中使用STM32F407标准库进行浮点运算非常简单。
首先，需要确保已经正确配置了Keil环境和编译器。
接下来，在Keil中创建一个新的工程，并选择适合的STM32F407芯片型号。
在工程文件夹中，可以找到名为
"STM32F4xx_StdPeriph_Lib"的文件夹，里面包含了标准库的所有头文件和源代码。
要在Keil中使用浮点运算，需要在编译选项中启用浮点支持。
打开项目属性对话框，选择"C/C++"选项，并在"预处理器选项"中添加__FPU_PRESENT宏定义。
此外，还需要选择正确的浮点单元类型（单精度或双精度），并设置浮点数的大小。
在代码中，可以使用标准库中提供的各种浮点运算函数。
例如，可以使用标准库中的浮点数加法函数"float32_t
arm_add_f32(float32_t op1, float32_t op2)"执行两个32位浮点数的加法运算。
除了基本的浮点运算函数外，标准库还提供了其他各种复杂的浮点运算函数，如三角函数、指数函数、对数函数等。
可以根据需要选择适当的函数使用。
总之，在Keil中使用STM32F407标准库进行浮点运算非常方便。
只需正确配置编译选项，并使用提供的浮点运算函数即可实现各种浮点运算操作。
STM32单片机的CPU运行性能的算法测试
此函数为操作系统的tick钩子函数，即每次产生系统tick中断都会进入到
此钩子函数。此钩子函数实际上就是具体计算CPU使用率的算法了。
osCPU_TotalIdleTime是一个全局变量，表示在1000个tick时间内空闲任务
configUSE_PREEMPTION 1
第三步：继续在FreeRTOSConfig.h头文件的末尾处添加
traceTASK_SWITCHED_IN与traceTASK_SWITCHED_OUT定义：
第四步：在main.h头文件中include“”cmsis_os.h“”
Main.h：
第五步：修改工程属性，使编译过程不需要函数原型：
第六步：在工程中任何用户代码处都可以调用osGetCPUUsage（）函数来
获取当前CPU的使用率：
第七步：编译并运行测试
在调试状态下使用Live Watch窗口监控全部变量osCPU_Usage的值：
osCPU_Usage是在cpu_utils.c文件中定义的全局变量，表示当前CPU的
使用率，是个动态值，由上图可以，CPU使用率的动态值为20%。实际在代
EndIdleMonitor（）则在推出空闲任务时计算此次空闲任务花费多长时间，并
累加到osCPU_TotalIdleTime，即空闲任务总共占用的时间片。
全局变量osCPU_Usage保存的就是CPU的使用率，它是在操作系统的
tick钩子函数中每隔1000个tick就被重新计算一次。
4结论
通过此方法可以很好的用来评估STM23 MCU的运行性能。
码中是按第六步中调用osGetCPUUsage（）函数来获取当前CPU的使用率
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STM32F4系列FPU开启及测试
◆要充分发挥STM32F4系列处理器FPU的数学性能，需要进行一
些设置：
1.编译控制选项。
在system_stm32f4XXX.c文件的system_init()函数里面添加如下代码（在keil5版本中不需要）：
/* FPU settings ------------------------------------------------------------*/
#if (__FPU_PRESENT == 1) && (__FPU_USED == 1)
SCB->CPACR |= ((3UL << 10*2)|(3UL << 11*2)); /* set CP10 and CP11 Full Access */
#endif
2.添加全局宏定义。
在工程选项（Project->Optionsfor target "XXXX"）中的C/C++选项卡的Define 中加入如下的语句（用逗号隔开）：
__FPU_USED=1
__FPU_PRESENT=1
ARM_MATH_CM4
__CC_ARM
ARM_MATH_MATRIX_CHECK
ARM_MATH_ROUNDING
3.keil中开启FPU。
在工程选项的“Target”选项卡里的“Code Generation”下的“Floating Point Hardware”下拉菜单中选择“Use FPU”（keil5以上版本可能为“Single Precision”）。
4.添加官方DSP库。
在工程文件中添加arm_cortexM4lf_math.lib库文件（位于\Libraries\CMSIS\Lib\ARM中），库提供浮点数的各种基本运算函数，如以_f32结尾的运算函数。
5.包含头文件。
在需要使用浮点运算的文件中#include<arm_math.h>。
注意：浮点数字后面要加上“f”否则带小数点的数据默认编译为双精度数据类型！
◆FPU基本运算性能测试
测试条件是在主函数中进行单精度加法、乘法、除法、三角函数、开方及双精度乘法运算，开启一个1s定时器，在中断服务函数中定时串口打印相关运算的计算次数。
将测试结果列于表1中。
表1 FPU运算性能测试结果
由表1可以大致得出以下结论：
1、FPU使单精度数据运算能力显著提升，但是对于双精度数据的运算则没有效
果；
2、浮点数据的除法运算比乘法运算更为耗时，而加法与乘法运算则耗时程度相
当；
3、越是复杂的运算，如三角函数、开方等，FPU对运算能力的改善越明显。
根据ST的官方文档，采用Julia集（一种算法，主要包含加减乘除等运算）对FPU进行测试时，得到速度的提升为14.57倍，而文档中速度提升约为17倍左右。