什么是模块化，怎么写一个好的C语言模块？通过标准库，开源库，驱动库学习

什么是模块化

1什么是模块化

模块化编程就是把我们的一整个项目，分成很多模块(比如一个学生成绩查询可以分为，登陆，查询，修改保存，退出等模块)

而一个程序工程包含多个源文件（.c 文件和 .h 文件），每个 .c 文件可以被称为一个模块，每一个模块都有其各自的功能，而每一个.h文件则是声明该模块，相当于功能说明书 模块化编程在嵌入式中为必须要掌握的技能

2为啥要用模块化

有的同学会想，我一个main.c也写得津津有道的，为什么偏要分开呢。

在我们实际应用中，当你的代码长度长起来了以后就会发现，想自己以前的代码里面找到之前定义的模块很麻烦，因为代码太多太繁杂了，你很难有一个清晰的分类，这就导致了代码的臃肿性，并且别人也很难看懂你的代码。

并且在实际项目开发的时候，一个复杂的项目意味着你需要和别人组成小组一起进行开发，这时候每个人负责一部分功能的开发，而你所负责的模块，你需要将你负责的模块功能写好，封装好，之后形成一个.c与.h 然后交付给项目组长，组长则负责整体框架(main)的编写与各个模块的组合调试，最后各个模块的组合，形成了整个工程。

这时候就可以彰显模块化的作用了，它使得整个项目分工明确，条理清晰，易于阅读，便于移植，等优点

模块化具体原理：

我们在写C语言代码的时候，首先做的就是引入头文件

在相对应的头文件引入之后，就可以使用相对应头文件里的函数，

比如 #include<stdio.h>

之后我们就可以使用printf scanf 语句进行数据的打印与获取，而printf和scanf语句的定义则是在stdio.h中，用户只需要负责调用即可

模块化编程的核心思想也正是如此： 将系统的各个功能进行封装，变成一个个独立的模块，其他人只需要使用你所提供的函数和变量等，就可以完成相对应的功能

模块化的本质也就是，新建一个.c和.h文件，

.c文件里面存放着你所构建的函数，功能，等等，而当你想让他可以被其他文件使用时，这时候便需要在对应的.H之中声明，

在外部调用时，只需要#include包含相对应的.h 即可

具体可以阅读：【C语言】----宏定义，预处理宏

3模块化基本代码实现：

我们以最简单的LED为例 ，将其分为一个模块

LED.h

#ifndef LED.h
 
#define LED.h
 
extern void LED_Open();   //开启LED灯 
 
extern void LED_Close();  //关闭LED灯
 
#endif

LED.c

void LED_Open()
 
{
  //亮灯代码
 
}
void LED_Close()
 
{
  //关灯代码
 
}

main.c 主函数

#include "LED.h"
 
int main(void)
{    
    LED_Open();  //开启LED灯
 
    while(1);
}

这样子你的LED部分的代码就会独立起来，需要使用时直接调用函数即可，修改也会变得十分简便

模块化的核心也就是各个模块独立封装，多个.c和.h 使得整个工程变得易于阅读，逻辑清晰

我们分布讲解

首先

#ifndef XXX 表示如果没有定义 xxx 则执行后面的语句 如果已经定义则不执行，

#define xxx 定义一个预处理宏定义，

#endif 表示条件命令的结束

我们这里#ifndef LED.h #define LED.h 表示如果没有定义LED.H这个头文件，则定义LED.h 并且后面的语句都有效，直到#endif 结束命令为止

同时声明了开LED灯和关LED灯两个函数

具体格式为：

 
#ifndef _XXX_h_
 
#define _XXX_h_
 
#endif
 

.c文件中：

#include "XXX.h"

.C文件

之后LED.c文件则是你所构建的函数，完成函数功能的编写，和变量的定义

最后在主函数或者其他函数中 #include LED.h 包含头文件，即可调用相对应声明的函数和变量

这便是一个模块的构建，而构建多个模块实现其各自功能，并且在主函数中分别调用，这便是模块化编程

比如我想要建立一个学生成绩管理系统，就可以分成几个模块，分别建立相对应的.c文件和.h文件，最后在主函数中调用相对应功能即可

c语言中条件编译相关的预编译指令

***#define 定义一个预处理宏
#undef 取消宏的定义

#if 编译预处理中的条件命令，相当于C语法中的if语句
#ifdef 判断某个宏是否被定义，若已定义，执行随后的语句
#ifndef 与#ifdef相反，判断某个宏是否未被定义
#elif 若#if, #ifdef, #ifndef或前面的#elif条件不满足，则执行#elif之后的语句，相当于C语法中的else-if
#else 与#if, #ifdef, #ifndef对应, 若这些条件不满足，则执行#else之后的语句，相当于C语法中的else
#endif #if, #ifdef, #ifndef这些条件命令的结束标志.
defined 　与#if, #elif配合使用，判断某个宏是否被定义***

具体可以阅读：【C语言】----宏定义，预处理宏

4模块化编程注意事项

头文件(XX.h)注意事项：

1.函数默认是extern属性 也就是我们声明函数的时候前面的extern可有可无

extern void LED_Open();   
 void LED_Open();   //相同

2.“.h”文件中不可以定义变量 在.h中只能声明，不能定义

#ifndef LED.h
#define LED.h
 
extern a;  //声明变量a  正确
b=3;        //定义变量b  错误
 
#endif

3声明变量不会占用内存，定义变量才会

定义变量和声明变量的区别在于定义会产生分配内存的操作，这是汇编阶段的概念；声明则只是告诉包含该声明的模块在连接阶段从其他模块寻找外部函数和变量。

4 不想让外界知道的信息，就不应该出现在头文件里，而想让外部调用的函数或变量，则一定要在头文件中声明

5 头文件(.h)命名应与源文件(.c)一致，便于清晰的查看各个头文件

6 #include <stdio.h>,#include “myfile.h”,双引号先在工程目录里寻找，再去系统目录里寻找。

.c文件(XX.c)注意事项：

1.模块内不想被外部引用的函数和全局变量需在“.c”文件头冠以static关键字声明。 这样这些函数和变量只会在当前.c文件中起到作用**，**一来可以避免函数名的重复；二来可以保护内部的实现数据，防止被破坏

static a = 3;
static void LED_Open();   

2模块中想要被其他文件访问的变量，一定要是全局变量，并且在.h中声明

3 要尽量减少全局变量的使用，因为全局变量的生命周期是从程序的开始到程序的结束的，这意味着你在其他源文件中调用这个变量时，可能会产生同名变量，以及变量数值错误等问题

4函数的声明有无extern都行，变量的声明必须加上extern，否则编译器无法识别声明。

extern static 关键字用法 请参看 【c语言】关键字存储类型讲解(auto,extern,static,register,const)

转载于：https://blog.csdn.net/as480133937/article/details/93400979

---

外设库，硬件库，驱动库

stm32f10x_gpio.h

/**
  ******************************************************************************
  * @file    stm32f10x_gpio.h
  * @author  MCD Application Team
  * @version V3.5.0
  * @date    11-March-2011
  * @brief   This file contains all the functions prototypes for the GPIO 
  *          firmware library.
  ******************************************************************************
  * @attention
  *
  * THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
  * WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE
  * TIME. AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY
  * DIRECT, INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING
  * FROM THE CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE
  * CODING INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
  *
  * <h2><center>&copy; COPYRIGHT 2011 STMicroelectronics</center></h2>
  ******************************************************************************
  */

/* Define to prevent recursive inclusion -------------------------------------*/
#ifndef __STM32F10x_GPIO_H
#define __STM32F10x_GPIO_H

#ifdef __cplusplus
 extern "C" {
#endif

/* Includes ------------------------------------------------------------------*/
#include "stm32f10x.h"

/** @addtogroup STM32F10x_StdPeriph_Driver
  * @{
  */

/** @addtogroup GPIO
  * @{
  */

/** @defgroup GPIO_Exported_Types
  * @{
  */

#define IS_GPIO_ALL_PERIPH(PERIPH) (((PERIPH) == GPIOA) || \
                                    ((PERIPH) == GPIOB) || \
                                    ((PERIPH) == GPIOC) || \
                                    ((PERIPH) == GPIOD) || \
                                    ((PERIPH) == GPIOE) || \
                                    ((PERIPH) == GPIOF) || \
                                    ((PERIPH) == GPIOG))
                                     
/** 
  * @brief  Output Maximum frequency selection  
  */

typedef enum
{ 
  GPIO_Speed_10MHz = 1,
  GPIO_Speed_2MHz, 
  GPIO_Speed_50MHz
}GPIOSpeed_TypeDef;
#define IS_GPIO_SPEED(SPEED) (((SPEED) == GPIO_Speed_10MHz) || ((SPEED) == GPIO_Speed_2MHz) || \
                              ((SPEED) == GPIO_Speed_50MHz))

/** 
  * @brief  Configuration Mode enumeration  
  */

typedef enum
{ GPIO_Mode_AIN = 0x0,
  GPIO_Mode_IN_FLOATING = 0x04,
  GPIO_Mode_IPD = 0x28,
  GPIO_Mode_IPU = 0x48,
  GPIO_Mode_Out_OD = 0x14,
  GPIO_Mode_Out_PP = 0x10,
  GPIO_Mode_AF_OD = 0x1C,
  GPIO_Mode_AF_PP = 0x18
}GPIOMode_TypeDef;

#define IS_GPIO_MODE(MODE) (((MODE) == GPIO_Mode_AIN) || ((MODE) == GPIO_Mode_IN_FLOATING) || \
                            ((MODE) == GPIO_Mode_IPD) || ((MODE) == GPIO_Mode_IPU) || \
                            ((MODE) == GPIO_Mode_Out_OD) || ((MODE) == GPIO_Mode_Out_PP) || \
                            ((MODE) == GPIO_Mode_AF_OD) || ((MODE) == GPIO_Mode_AF_PP))

/** 
  * @brief  GPIO Init structure definition  
  */

typedef struct
{
  uint16_t GPIO_Pin;             /*!< Specifies the GPIO pins to be configured.
                                      This parameter can be any value of @ref GPIO_pins_define */

  GPIOSpeed_TypeDef GPIO_Speed;  /*!< Specifies the speed for the selected pins.
                                      This parameter can be a value of @ref GPIOSpeed_TypeDef */

  GPIOMode_TypeDef GPIO_Mode;    /*!< Specifies the operating mode for the selected pins.
                                      This parameter can be a value of @ref GPIOMode_TypeDef */
}GPIO_InitTypeDef;


/** 
  * @brief  Bit_SET and Bit_RESET enumeration  
  */

typedef enum
{ Bit_RESET = 0,
  Bit_SET
}BitAction;

#define IS_GPIO_BIT_ACTION(ACTION) (((ACTION) == Bit_RESET) || ((ACTION) == Bit_SET))

/**
  * @}
  */

/** @defgroup GPIO_Exported_Constants
  * @{
  */

/** @defgroup GPIO_pins_define 
  * @{
  */

#define GPIO_Pin_0                 ((uint16_t)0x0001)  /*!< Pin 0 selected */
#define GPIO_Pin_1                 ((uint16_t)0x0002)  /*!< Pin 1 selected */
#define GPIO_Pin_2                 ((uint16_t)0x0004)  /*!< Pin 2 selected */
#define GPIO_Pin_3                 ((uint16_t)0x0008)  /*!< Pin 3 selected */
#define GPIO_Pin_4                 ((uint16_t)0x0010)  /*!< Pin 4 selected */
#define GPIO_Pin_5                 ((uint16_t)0x0020)  /*!< Pin 5 selected */
#define GPIO_Pin_6                 ((uint16_t)0x0040)  /*!< Pin 6 selected */
#define GPIO_Pin_7                 ((uint16_t)0x0080)  /*!< Pin 7 selected */
#define GPIO_Pin_8                 ((uint16_t)0x0100)  /*!< Pin 8 selected */
#define GPIO_Pin_9                 ((uint16_t)0x0200)  /*!< Pin 9 selected */
#define GPIO_Pin_10                ((uint16_t)0x0400)  /*!< Pin 10 selected */
#define GPIO_Pin_11                ((uint16_t)0x0800)  /*!< Pin 11 selected */
#define GPIO_Pin_12                ((uint16_t)0x1000)  /*!< Pin 12 selected */
#define GPIO_Pin_13                ((uint16_t)0x2000)  /*!< Pin 13 selected */
#define GPIO_Pin_14                ((uint16_t)0x4000)  /*!< Pin 14 selected */
#define GPIO_Pin_15                ((uint16_t)0x8000)  /*!< Pin 15 selected */
#define GPIO_Pin_All               ((uint16_t)0xFFFF)  /*!< All pins selected */

#define IS_GPIO_PIN(PIN) ((((PIN) & (uint16_t)0x00) == 0x00) && ((PIN) != (uint16_t)0x00))

#define IS_GET_GPIO_PIN(PIN) (((PIN) == GPIO_Pin_0) || \
                              ((PIN) == GPIO_Pin_1) || \
                              ((PIN) == GPIO_Pin_2) || \
                              ((PIN) == GPIO_Pin_3) || \
                              ((PIN) == GPIO_Pin_4) || \
                              ((PIN) == GPIO_Pin_5) || \
                              ((PIN) == GPIO_Pin_6) || \
                              ((PIN) == GPIO_Pin_7) || \
                              ((PIN) == GPIO_Pin_8) || \
                              ((PIN) == GPIO_Pin_9) || \
                              ((PIN) == GPIO_Pin_10) || \
                              ((PIN) == GPIO_Pin_11) || \
                              ((PIN) == GPIO_Pin_12) || \
                              ((PIN) == GPIO_Pin_13) || \
                              ((PIN) == GPIO_Pin_14) || \
                              ((PIN) == GPIO_Pin_15))

/**
  * @}
  */

/** @defgroup GPIO_Remap_define 
  * @{
  */

#define GPIO_Remap_SPI1             ((uint32_t)0x00000001)  /*!< SPI1 Alternate Function mapping */
#define GPIO_Remap_I2C1             ((uint32_t)0x00000002)  /*!< I2C1 Alternate Function mapping */
#define GPIO_Remap_USART1           ((uint32_t)0x00000004)  /*!< USART1 Alternate Function mapping */
#define GPIO_Remap_USART2           ((uint32_t)0x00000008)  /*!< USART2 Alternate Function mapping */
#define GPIO_PartialRemap_USART3    ((uint32_t)0x00140010)  /*!< USART3 Partial Alternate Function mapping */
#define GPIO_FullRemap_USART3       ((uint32_t)0x00140030)  /*!< USART3 Full Alternate Function mapping */
#define GPIO_PartialRemap_TIM1      ((uint32_t)0x00160040)  /*!< TIM1 Partial Alternate Function mapping */
#define GPIO_FullRemap_TIM1         ((uint32_t)0x001600C0)  /*!< TIM1 Full Alternate Function mapping */
#define GPIO_PartialRemap1_TIM2     ((uint32_t)0x00180100)  /*!< TIM2 Partial1 Alternate Function mapping */
#define GPIO_PartialRemap2_TIM2     ((uint32_t)0x00180200)  /*!< TIM2 Partial2 Alternate Function mapping */
#define GPIO_FullRemap_TIM2         ((uint32_t)0x00180300)  /*!< TIM2 Full Alternate Function mapping */
#define GPIO_PartialRemap_TIM3      ((uint32_t)0x001A0800)  /*!< TIM3 Partial Alternate Function mapping */
#define GPIO_FullRemap_TIM3         ((uint32_t)0x001A0C00)  /*!< TIM3 Full Alternate Function mapping */
#define GPIO_Remap_TIM4             ((uint32_t)0x00001000)  /*!< TIM4 Alternate Function mapping */
#define GPIO_Remap1_CAN1            ((uint32_t)0x001D4000)  /*!< CAN1 Alternate Function mapping */
#define GPIO_Remap2_CAN1            ((uint32_t)0x001D6000)  /*!< CAN1 Alternate Function mapping */
#define GPIO_Remap_PD01             ((uint32_t)0x00008000)  /*!< PD01 Alternate Function mapping */
#define GPIO_Remap_TIM5CH4_LSI      ((uint32_t)0x00200001)  /*!< LSI connected to TIM5 Channel4 input capture for calibration */
#define GPIO_Remap_ADC1_ETRGINJ     ((uint32_t)0x00200002)  /*!< ADC1 External Trigger Injected Conversion remapping */
#define GPIO_Remap_ADC1_ETRGREG     ((uint32_t)0x00200004)  /*!< ADC1 External Trigger Regular Conversion remapping */
#define GPIO_Remap_ADC2_ETRGINJ     ((uint32_t)0x00200008)  /*!< ADC2 External Trigger Injected Conversion remapping */
#define GPIO_Remap_ADC2_ETRGREG     ((uint32_t)0x00200010)  /*!< ADC2 External Trigger Regular Conversion remapping */
#define GPIO_Remap_ETH              ((uint32_t)0x00200020)  /*!< Ethernet remapping (only for Connectivity line devices) */
#define GPIO_Remap_CAN2             ((uint32_t)0x00200040)  /*!< CAN2 remapping (only for Connectivity line devices) */
#define GPIO_Remap_SWJ_NoJTRST      ((uint32_t)0x00300100)  /*!< Full SWJ Enabled (JTAG-DP + SW-DP) but without JTRST */
#define GPIO_Remap_SWJ_JTAGDisable  ((uint32_t)0x00300200)  /*!< JTAG-DP Disabled and SW-DP Enabled */
#define GPIO_Remap_SWJ_Disable      ((uint32_t)0x00300400)  /*!< Full SWJ Disabled (JTAG-DP + SW-DP) */
#define GPIO_Remap_SPI3             ((uint32_t)0x00201100)  /*!< SPI3/I2S3 Alternate Function mapping (only for Connectivity line devices) */
#define GPIO_Remap_TIM2ITR1_PTP_SOF ((uint32_t)0x00202000)  /*!< Ethernet PTP output or USB OTG SOF (Start of Frame) connected
                                                                 to TIM2 Internal Trigger 1 for calibration
                                                                 (only for Connectivity line devices) */
#define GPIO_Remap_PTP_PPS          ((uint32_t)0x00204000)  /*!< Ethernet MAC PPS_PTS output on PB05 (only for Connectivity line devices) */

#define GPIO_Remap_TIM15            ((uint32_t)0x80000001)  /*!< TIM15 Alternate Function mapping (only for Value line devices) */
#define GPIO_Remap_TIM16            ((uint32_t)0x80000002)  /*!< TIM16 Alternate Function mapping (only for Value line devices) */
#define GPIO_Remap_TIM17            ((uint32_t)0x80000004)  /*!< TIM17 Alternate Function mapping (only for Value line devices) */
#define GPIO_Remap_CEC              ((uint32_t)0x80000008)  /*!< CEC Alternate Function mapping (only for Value line devices) */
#define GPIO_Remap_TIM1_DMA         ((uint32_t)0x80000010)  /*!< TIM1 DMA requests mapping (only for Value line devices) */

#define GPIO_Remap_TIM9             ((uint32_t)0x80000020)  /*!< TIM9 Alternate Function mapping (only for XL-density devices) */
#define GPIO_Remap_TIM10            ((uint32_t)0x80000040)  /*!< TIM10 Alternate Function mapping (only for XL-density devices) */
#define GPIO_Remap_TIM11            ((uint32_t)0x80000080)  /*!< TIM11 Alternate Function mapping (only for XL-density devices) */
#define GPIO_Remap_TIM13            ((uint32_t)0x80000100)  /*!< TIM13 Alternate Function mapping (only for High density Value line and XL-density devices) */
#define GPIO_Remap_TIM14            ((uint32_t)0x80000200)  /*!< TIM14 Alternate Function mapping (only for High density Value line and XL-density devices) */
#define GPIO_Remap_FSMC_NADV        ((uint32_t)0x80000400)  /*!< FSMC_NADV Alternate Function mapping (only for High density Value line and XL-density devices) */

#define GPIO_Remap_TIM67_DAC_DMA    ((uint32_t)0x80000800)  /*!< TIM6/TIM7 and DAC DMA requests remapping (only for High density Value line devices) */
#define GPIO_Remap_TIM12            ((uint32_t)0x80001000)  /*!< TIM12 Alternate Function mapping (only for High density Value line devices) */
#define GPIO_Remap_MISC             ((uint32_t)0x80002000)  /*!< Miscellaneous Remap (DMA2 Channel5 Position and DAC Trigger remapping, 
                                                                 only for High density Value line devices) */                                                       

#define IS_GPIO_REMAP(REMAP) (((REMAP) == GPIO_Remap_SPI1) || ((REMAP) == GPIO_Remap_I2C1) || \
                              ((REMAP) == GPIO_Remap_USART1) || ((REMAP) == GPIO_Remap_USART2) || \
                              ((REMAP) == GPIO_PartialRemap_USART3) || ((REMAP) == GPIO_FullRemap_USART3) || \
                              ((REMAP) == GPIO_PartialRemap_TIM1) || ((REMAP) == GPIO_FullRemap_TIM1) || \
                              ((REMAP) == GPIO_PartialRemap1_TIM2) || ((REMAP) == GPIO_PartialRemap2_TIM2) || \
                              ((REMAP) == GPIO_FullRemap_TIM2) || ((REMAP) == GPIO_PartialRemap_TIM3) || \
                              ((REMAP) == GPIO_FullRemap_TIM3) || ((REMAP) == GPIO_Remap_TIM4) || \
                              ((REMAP) == GPIO_Remap1_CAN1) || ((REMAP) == GPIO_Remap2_CAN1) || \
                              ((REMAP) == GPIO_Remap_PD01) || ((REMAP) == GPIO_Remap_TIM5CH4_LSI) || \
                              ((REMAP) == GPIO_Remap_ADC1_ETRGINJ) ||((REMAP) == GPIO_Remap_ADC1_ETRGREG) || \
                              ((REMAP) == GPIO_Remap_ADC2_ETRGINJ) ||((REMAP) == GPIO_Remap_ADC2_ETRGREG) || \
                              ((REMAP) == GPIO_Remap_ETH) ||((REMAP) == GPIO_Remap_CAN2) || \
                              ((REMAP) == GPIO_Remap_SWJ_NoJTRST) || ((REMAP) == GPIO_Remap_SWJ_JTAGDisable) || \
                              ((REMAP) == GPIO_Remap_SWJ_Disable)|| ((REMAP) == GPIO_Remap_SPI3) || \
                              ((REMAP) == GPIO_Remap_TIM2ITR1_PTP_SOF) || ((REMAP) == GPIO_Remap_PTP_PPS) || \
                              ((REMAP) == GPIO_Remap_TIM15) || ((REMAP) == GPIO_Remap_TIM16) || \
                              ((REMAP) == GPIO_Remap_TIM17) || ((REMAP) == GPIO_Remap_CEC) || \
                              ((REMAP) == GPIO_Remap_TIM1_DMA) || ((REMAP) == GPIO_Remap_TIM9) || \
                              ((REMAP) == GPIO_Remap_TIM10) || ((REMAP) == GPIO_Remap_TIM11) || \
                              ((REMAP) == GPIO_Remap_TIM13) || ((REMAP) == GPIO_Remap_TIM14) || \
                              ((REMAP) == GPIO_Remap_FSMC_NADV) || ((REMAP) == GPIO_Remap_TIM67_DAC_DMA) || \
                              ((REMAP) == GPIO_Remap_TIM12) || ((REMAP) == GPIO_Remap_MISC))
                              
/**
  * @}
  */ 

/** @defgroup GPIO_Port_Sources 
  * @{
  */

#define GPIO_PortSourceGPIOA       ((uint8_t)0x00)
#define GPIO_PortSourceGPIOB       ((uint8_t)0x01)
#define GPIO_PortSourceGPIOC       ((uint8_t)0x02)
#define GPIO_PortSourceGPIOD       ((uint8_t)0x03)
#define GPIO_PortSourceGPIOE       ((uint8_t)0x04)
#define GPIO_PortSourceGPIOF       ((uint8_t)0x05)
#define GPIO_PortSourceGPIOG       ((uint8_t)0x06)
#define IS_GPIO_EVENTOUT_PORT_SOURCE(PORTSOURCE) (((PORTSOURCE) == GPIO_PortSourceGPIOA) || \
                                                  ((PORTSOURCE) == GPIO_PortSourceGPIOB) || \
                                                  ((PORTSOURCE) == GPIO_PortSourceGPIOC) || \
                                                  ((PORTSOURCE) == GPIO_PortSourceGPIOD) || \
                                                  ((PORTSOURCE) == GPIO_PortSourceGPIOE))

#define IS_GPIO_EXTI_PORT_SOURCE(PORTSOURCE) (((PORTSOURCE) == GPIO_PortSourceGPIOA) || \
                                              ((PORTSOURCE) == GPIO_PortSourceGPIOB) || \
                                              ((PORTSOURCE) == GPIO_PortSourceGPIOC) || \
                                              ((PORTSOURCE) == GPIO_PortSourceGPIOD) || \
                                              ((PORTSOURCE) == GPIO_PortSourceGPIOE) || \
                                              ((PORTSOURCE) == GPIO_PortSourceGPIOF) || \
                                              ((PORTSOURCE) == GPIO_PortSourceGPIOG))

/**
  * @}
  */

/** @defgroup GPIO_Pin_sources 
  * @{
  */

#define GPIO_PinSource0            ((uint8_t)0x00)
#define GPIO_PinSource1            ((uint8_t)0x01)
#define GPIO_PinSource2            ((uint8_t)0x02)
#define GPIO_PinSource3            ((uint8_t)0x03)
#define GPIO_PinSource4            ((uint8_t)0x04)
#define GPIO_PinSource5            ((uint8_t)0x05)
#define GPIO_PinSource6            ((uint8_t)0x06)
#define GPIO_PinSource7            ((uint8_t)0x07)
#define GPIO_PinSource8            ((uint8_t)0x08)
#define GPIO_PinSource9            ((uint8_t)0x09)
#define GPIO_PinSource10           ((uint8_t)0x0A)
#define GPIO_PinSource11           ((uint8_t)0x0B)
#define GPIO_PinSource12           ((uint8_t)0x0C)
#define GPIO_PinSource13           ((uint8_t)0x0D)
#define GPIO_PinSource14           ((uint8_t)0x0E)
#define GPIO_PinSource15           ((uint8_t)0x0F)

#define IS_GPIO_PIN_SOURCE(PINSOURCE) (((PINSOURCE) == GPIO_PinSource0) || \
                                       ((PINSOURCE) == GPIO_PinSource1) || \
                                       ((PINSOURCE) == GPIO_PinSource2) || \
                                       ((PINSOURCE) == GPIO_PinSource3) || \
                                       ((PINSOURCE) == GPIO_PinSource4) || \
                                       ((PINSOURCE) == GPIO_PinSource5) || \
                                       ((PINSOURCE) == GPIO_PinSource6) || \
                                       ((PINSOURCE) == GPIO_PinSource7) || \
                                       ((PINSOURCE) == GPIO_PinSource8) || \
                                       ((PINSOURCE) == GPIO_PinSource9) || \
                                       ((PINSOURCE) == GPIO_PinSource10) || \
                                       ((PINSOURCE) == GPIO_PinSource11) || \
                                       ((PINSOURCE) == GPIO_PinSource12) || \
                                       ((PINSOURCE) == GPIO_PinSource13) || \
                                       ((PINSOURCE) == GPIO_PinSource14) || \
                                       ((PINSOURCE) == GPIO_PinSource15))

/**
  * @}
  */

/** @defgroup Ethernet_Media_Interface 
  * @{
  */ 
#define GPIO_ETH_MediaInterface_MII    ((u32)0x00000000) 
#define GPIO_ETH_MediaInterface_RMII   ((u32)0x00000001)                                       

#define IS_GPIO_ETH_MEDIA_INTERFACE(INTERFACE) (((INTERFACE) == GPIO_ETH_MediaInterface_MII) || \
                                                ((INTERFACE) == GPIO_ETH_MediaInterface_RMII))

/**
  * @}
  */                                                
/**
  * @}
  */

/** @defgroup GPIO_Exported_Macros
  * @{
  */

/**
  * @}
  */

/** @defgroup GPIO_Exported_Functions
  * @{
  */

void GPIO_DeInit(GPIO_TypeDef* GPIOx);
void GPIO_AFIODeInit(void);
void GPIO_Init(GPIO_TypeDef* GPIOx, GPIO_InitTypeDef* GPIO_InitStruct);
void GPIO_StructInit(GPIO_InitTypeDef* GPIO_InitStruct);
uint8_t GPIO_ReadInputDataBit(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin);
uint16_t GPIO_ReadInputData(GPIO_TypeDef* GPIOx);
uint8_t GPIO_ReadOutputDataBit(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin);
uint16_t GPIO_ReadOutputData(GPIO_TypeDef* GPIOx);
void GPIO_SetBits(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin);
void GPIO_ResetBits(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin);
void GPIO_WriteBit(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin, BitAction BitVal);
void GPIO_Write(GPIO_TypeDef* GPIOx, uint16_t PortVal);
void GPIO_PinLockConfig(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin);
void GPIO_EventOutputConfig(uint8_t GPIO_PortSource, uint8_t GPIO_PinSource);
void GPIO_EventOutputCmd(FunctionalState NewState);
void GPIO_PinRemapConfig(uint32_t GPIO_Remap, FunctionalState NewState);
void GPIO_EXTILineConfig(uint8_t GPIO_PortSource, uint8_t GPIO_PinSource);
void GPIO_ETH_MediaInterfaceConfig(uint32_t GPIO_ETH_MediaInterface);

#ifdef __cplusplus
}
#endif

#endif /* __STM32F10x_GPIO_H */
/**
  * @}
  */

/**
  * @}
  */

/**
  * @}
  */

/******************* (C) COPYRIGHT 2011 STMicroelectronics *****END OF FILE****/

stm32f10x_gpio.c

/**
  ******************************************************************************
  * @file    stm32f10x_gpio.c
  * @author  MCD Application Team
  * @version V3.5.0
  * @date    11-March-2011
  * @brief   This file provides all the GPIO firmware functions.
  ******************************************************************************
  * @attention
  *
  * THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
  * WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE
  * TIME. AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY
  * DIRECT, INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING
  * FROM THE CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE
  * CODING INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
  *
  * <h2><center>&copy; COPYRIGHT 2011 STMicroelectronics</center></h2>
  ******************************************************************************
  */

/* Includes ------------------------------------------------------------------*/
#include "stm32f10x_gpio.h"
#include "stm32f10x_rcc.h"

/** @addtogroup STM32F10x_StdPeriph_Driver
  * @{
  */

/** @defgroup GPIO 
  * @brief GPIO driver modules
  * @{
  */ 

/** @defgroup GPIO_Private_TypesDefinitions
  * @{
  */

/**
  * @}
  */

/** @defgroup GPIO_Private_Defines
  * @{
  */

/* ------------ RCC registers bit address in the alias region ----------------*/
#define AFIO_OFFSET                 (AFIO_BASE - PERIPH_BASE)

/* --- EVENTCR Register -----*/

/* Alias word address of EVOE bit */
#define EVCR_OFFSET                 (AFIO_OFFSET + 0x00)
#define EVOE_BitNumber              ((uint8_t)0x07)
#define EVCR_EVOE_BB                (PERIPH_BB_BASE + (EVCR_OFFSET * 32) + (EVOE_BitNumber * 4))


/* ---  MAPR Register ---*/ 
/* Alias word address of MII_RMII_SEL bit */ 
#define MAPR_OFFSET                 (AFIO_OFFSET + 0x04) 
#define MII_RMII_SEL_BitNumber      ((u8)0x17) 
#define MAPR_MII_RMII_SEL_BB        (PERIPH_BB_BASE + (MAPR_OFFSET * 32) + (MII_RMII_SEL_BitNumber * 4))


#define EVCR_PORTPINCONFIG_MASK     ((uint16_t)0xFF80)
#define LSB_MASK                    ((uint16_t)0xFFFF)
#define DBGAFR_POSITION_MASK        ((uint32_t)0x000F0000)
#define DBGAFR_SWJCFG_MASK          ((uint32_t)0xF0FFFFFF)
#define DBGAFR_LOCATION_MASK        ((uint32_t)0x00200000)
#define DBGAFR_NUMBITS_MASK         ((uint32_t)0x00100000)
/**
  * @}
  */

/** @defgroup GPIO_Private_Macros
  * @{
  */

/**
  * @}
  */

/** @defgroup GPIO_Private_Variables
  * @{
  */

/**
  * @}
  */

/** @defgroup GPIO_Private_FunctionPrototypes
  * @{
  */

/**
  * @}
  */

/** @defgroup GPIO_Private_Functions
  * @{
  */

/**
  * @brief  Deinitializes the GPIOx peripheral registers to their default reset values.
  * @param  GPIOx: where x can be (A..G) to select the GPIO peripheral.
  * @retval None
  */
void GPIO_DeInit(GPIO_TypeDef* GPIOx)
{
  /* Check the parameters */
  assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
  
  if (GPIOx == GPIOA)
  {
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOA, ENABLE);
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOA, DISABLE);
  }
  else if (GPIOx == GPIOB)
  {
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOB, ENABLE);
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOB, DISABLE);
  }
  else if (GPIOx == GPIOC)
  {
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOC, ENABLE);
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOC, DISABLE);
  }
  else if (GPIOx == GPIOD)
  {
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOD, ENABLE);
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOD, DISABLE);
  }    
  else if (GPIOx == GPIOE)
  {
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOE, ENABLE);
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOE, DISABLE);
  } 
  else if (GPIOx == GPIOF)
  {
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOF, ENABLE);
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOF, DISABLE);
  }
  else
  {
    if (GPIOx == GPIOG)
    {
      RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOG, ENABLE);
      RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOG, DISABLE);
    }
  }
}

/**
  * @brief  Deinitializes the Alternate Functions (remap, event control
  *   and EXTI configuration) registers to their default reset values.
  * @param  None
  * @retval None
  */
void GPIO_AFIODeInit(void)
{
  RCC_APB2PeriphResetCmd(RCC_APB2Periph_AFIO, ENABLE);
  RCC_APB2PeriphResetCmd(RCC_APB2Periph_AFIO, DISABLE);
}

/**
  * @brief  Initializes the GPIOx peripheral according to the specified
  *         parameters in the GPIO_InitStruct.
  * @param  GPIOx: where x can be (A..G) to select the GPIO peripheral.
  * @param  GPIO_InitStruct: pointer to a GPIO_InitTypeDef structure that
  *         contains the configuration information for the specified GPIO peripheral.
  * @retval None
  */
void GPIO_Init(GPIO_TypeDef* GPIOx, GPIO_InitTypeDef* GPIO_InitStruct)
{
  uint32_t currentmode = 0x00, currentpin = 0x00, pinpos = 0x00, pos = 0x00;
  uint32_t tmpreg = 0x00, pinmask = 0x00;
  /* Check the parameters */
  assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
  assert_param(IS_GPIO_MODE(GPIO_InitStruct->GPIO_Mode));
  assert_param(IS_GPIO_PIN(GPIO_InitStruct->GPIO_Pin));  
  
/*---------------------------- GPIO Mode Configuration -----------------------*/
  currentmode = ((uint32_t)GPIO_InitStruct->GPIO_Mode) & ((uint32_t)0x0F);
  if ((((uint32_t)GPIO_InitStruct->GPIO_Mode) & ((uint32_t)0x10)) != 0x00)
  { 
    /* Check the parameters */
    assert_param(IS_GPIO_SPEED(GPIO_InitStruct->GPIO_Speed));
    /* Output mode */
    currentmode |= (uint32_t)GPIO_InitStruct->GPIO_Speed;
  }
/*---------------------------- GPIO CRL Configuration ------------------------*/
  /* Configure the eight low port pins */
  if (((uint32_t)GPIO_InitStruct->GPIO_Pin & ((uint32_t)0x00FF)) != 0x00)
  {
    tmpreg = GPIOx->CRL;
    for (pinpos = 0x00; pinpos < 0x08; pinpos++)
    {
      pos = ((uint32_t)0x01) << pinpos;
      /* Get the port pins position */
      currentpin = (GPIO_InitStruct->GPIO_Pin) & pos;
      if (currentpin == pos)
      {
        pos = pinpos << 2;
        /* Clear the corresponding low control register bits */
        pinmask = ((uint32_t)0x0F) << pos;
        tmpreg &= ~pinmask;
        /* Write the mode configuration in the corresponding bits */
        tmpreg |= (currentmode << pos);
        /* Reset the corresponding ODR bit */
        if (GPIO_InitStruct->GPIO_Mode == GPIO_Mode_IPD)
        {
          GPIOx->BRR = (((uint32_t)0x01) << pinpos);
        }
        else
        {
          /* Set the corresponding ODR bit */
          if (GPIO_InitStruct->GPIO_Mode == GPIO_Mode_IPU)
          {
            GPIOx->BSRR = (((uint32_t)0x01) << pinpos);
          }
        }
      }
    }
    GPIOx->CRL = tmpreg;
  }
/*---------------------------- GPIO CRH Configuration ------------------------*/
  /* Configure the eight high port pins */
  if (GPIO_InitStruct->GPIO_Pin > 0x00FF)
  {
    tmpreg = GPIOx->CRH;
    for (pinpos = 0x00; pinpos < 0x08; pinpos++)
    {
      pos = (((uint32_t)0x01) << (pinpos + 0x08));
      /* Get the port pins position */
      currentpin = ((GPIO_InitStruct->GPIO_Pin) & pos);
      if (currentpin == pos)
      {
        pos = pinpos << 2;
        /* Clear the corresponding high control register bits */
        pinmask = ((uint32_t)0x0F) << pos;
        tmpreg &= ~pinmask;
        /* Write the mode configuration in the corresponding bits */
        tmpreg |= (currentmode << pos);
        /* Reset the corresponding ODR bit */
        if (GPIO_InitStruct->GPIO_Mode == GPIO_Mode_IPD)
        {
          GPIOx->BRR = (((uint32_t)0x01) << (pinpos + 0x08));
        }
        /* Set the corresponding ODR bit */
        if (GPIO_InitStruct->GPIO_Mode == GPIO_Mode_IPU)
        {
          GPIOx->BSRR = (((uint32_t)0x01) << (pinpos + 0x08));
        }
      }
    }
    GPIOx->CRH = tmpreg;
  }
}

/**
  * @brief  Fills each GPIO_InitStruct member with its default value.
  * @param  GPIO_InitStruct : pointer to a GPIO_InitTypeDef structure which will
  *         be initialized.
  * @retval None
  */
void GPIO_StructInit(GPIO_InitTypeDef* GPIO_InitStruct)
{
  /* Reset GPIO init structure parameters values */
  GPIO_InitStruct->GPIO_Pin  = GPIO_Pin_All;
  GPIO_InitStruct->GPIO_Speed = GPIO_Speed_2MHz;
  GPIO_InitStruct->GPIO_Mode = GPIO_Mode_IN_FLOATING;
}

/**
  * @brief  Reads the specified input port pin.
  * @param  GPIOx: where x can be (A..G) to select the GPIO peripheral.
  * @param  GPIO_Pin:  specifies the port bit to read.
  *   This parameter can be GPIO_Pin_x where x can be (0..15).
  * @retval The input port pin value.
  */
uint8_t GPIO_ReadInputDataBit(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin)
{
  uint8_t bitstatus = 0x00;
  
  /* Check the parameters */
  assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
  assert_param(IS_GET_GPIO_PIN(GPIO_Pin)); 
  
  if ((GPIOx->IDR & GPIO_Pin) != (uint32_t)Bit_RESET)
  {
    bitstatus = (uint8_t)Bit_SET;
  }
  else
  {
    bitstatus = (uint8_t)Bit_RESET;
  }
  return bitstatus;
}

/**
  * @brief  Reads the specified GPIO input data port.
  * @param  GPIOx: where x can be (A..G) to select the GPIO peripheral.
  * @retval GPIO input data port value.
  */
uint16_t GPIO_ReadInputData(GPIO_TypeDef* GPIOx)
{
  /* Check the parameters */
  assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
  
  return ((uint16_t)GPIOx->IDR);
}

/**
  * @brief  Reads the specified output data port bit.
  * @param  GPIOx: where x can be (A..G) to select the GPIO peripheral.
  * @param  GPIO_Pin:  specifies the port bit to read.
  *   This parameter can be GPIO_Pin_x where x can be (0..15).
  * @retval The output port pin value.
  */
uint8_t GPIO_ReadOutputDataBit(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin)
{
  uint8_t bitstatus = 0x00;
  /* Check the parameters */
  assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
  assert_param(IS_GET_GPIO_PIN(GPIO_Pin)); 
  
  if ((GPIOx->ODR & GPIO_Pin) != (uint32_t)Bit_RESET)
  {
    bitstatus = (uint8_t)Bit_SET;
  }
  else
  {
    bitstatus = (uint8_t)Bit_RESET;
  }
  return bitstatus;
}

/**
  * @brief  Reads the specified GPIO output data port.
  * @param  GPIOx: where x can be (A..G) to select the GPIO peripheral.
  * @retval GPIO output data port value.
  */
uint16_t GPIO_ReadOutputData(GPIO_TypeDef* GPIOx)
{
  /* Check the parameters */
  assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
    
  return ((uint16_t)GPIOx->ODR);
}

/**
  * @brief  Sets the selected data port bits.
  * @param  GPIOx: where x can be (A..G) to select the GPIO peripheral.
  * @param  GPIO_Pin: specifies the port bits to be written.
  *   This parameter can be any combination of GPIO_Pin_x where x can be (0..15).
  * @retval None
  */
void GPIO_SetBits(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin)
{
  /* Check the parameters */
  assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
  assert_param(IS_GPIO_PIN(GPIO_Pin));
  
  GPIOx->BSRR = GPIO_Pin;
}

/**
  * @brief  Clears the selected data port bits.
  * @param  GPIOx: where x can be (A..G) to select the GPIO peripheral.
  * @param  GPIO_Pin: specifies the port bits to be written.
  *   This parameter can be any combination of GPIO_Pin_x where x can be (0..15).
  * @retval None
  */
void GPIO_ResetBits(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin)
{
  /* Check the parameters */
  assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
  assert_param(IS_GPIO_PIN(GPIO_Pin));
  
  GPIOx->BRR = GPIO_Pin;
}

/**
  * @brief  Sets or clears the selected data port bit.
  * @param  GPIOx: where x can be (A..G) to select the GPIO peripheral.
  * @param  GPIO_Pin: specifies the port bit to be written.
  *   This parameter can be one of GPIO_Pin_x where x can be (0..15).
  * @param  BitVal: specifies the value to be written to the selected bit.
  *   This parameter can be one of the BitAction enum values:
  *     @arg Bit_RESET: to clear the port pin
  *     @arg Bit_SET: to set the port pin
  * @retval None
  */
void GPIO_WriteBit(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin, BitAction BitVal)
{
  /* Check the parameters */
  assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
  assert_param(IS_GET_GPIO_PIN(GPIO_Pin));
  assert_param(IS_GPIO_BIT_ACTION(BitVal)); 
  
  if (BitVal != Bit_RESET)
  {
    GPIOx->BSRR = GPIO_Pin;
  }
  else
  {
    GPIOx->BRR = GPIO_Pin;
  }
}

/**
  * @brief  Writes data to the specified GPIO data port.
  * @param  GPIOx: where x can be (A..G) to select the GPIO peripheral.
  * @param  PortVal: specifies the value to be written to the port output data register.
  * @retval None
  */
void GPIO_Write(GPIO_TypeDef* GPIOx, uint16_t PortVal)
{
  /* Check the parameters */
  assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
  
  GPIOx->ODR = PortVal;
}

/**
  * @brief  Locks GPIO Pins configuration registers.
  * @param  GPIOx: where x can be (A..G) to select the GPIO peripheral.
  * @param  GPIO_Pin: specifies the port bit to be written.
  *   This parameter can be any combination of GPIO_Pin_x where x can be (0..15).
  * @retval None
  */
void GPIO_PinLockConfig(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin)
{
  uint32_t tmp = 0x00010000;
  
  /* Check the parameters */
  assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
  assert_param(IS_GPIO_PIN(GPIO_Pin));
  
  tmp |= GPIO_Pin;
  /* Set LCKK bit */
  GPIOx->LCKR = tmp;
  /* Reset LCKK bit */
  GPIOx->LCKR =  GPIO_Pin;
  /* Set LCKK bit */
  GPIOx->LCKR = tmp;
  /* Read LCKK bit*/
  tmp = GPIOx->LCKR;
  /* Read LCKK bit*/
  tmp = GPIOx->LCKR;
}

/**
  * @brief  Selects the GPIO pin used as Event output.
  * @param  GPIO_PortSource: selects the GPIO port to be used as source
  *   for Event output.
  *   This parameter can be GPIO_PortSourceGPIOx where x can be (A..E).
  * @param  GPIO_PinSource: specifies the pin for the Event output.
  *   This parameter can be GPIO_PinSourcex where x can be (0..15).
  * @retval None
  */
void GPIO_EventOutputConfig(uint8_t GPIO_PortSource, uint8_t GPIO_PinSource)
{
  uint32_t tmpreg = 0x00;
  /* Check the parameters */
  assert_param(IS_GPIO_EVENTOUT_PORT_SOURCE(GPIO_PortSource));
  assert_param(IS_GPIO_PIN_SOURCE(GPIO_PinSource));
    
  tmpreg = AFIO->EVCR;
  /* Clear the PORT[6:4] and PIN[3:0] bits */
  tmpreg &= EVCR_PORTPINCONFIG_MASK;
  tmpreg |= (uint32_t)GPIO_PortSource << 0x04;
  tmpreg |= GPIO_PinSource;
  AFIO->EVCR = tmpreg;
}

/**
  * @brief  Enables or disables the Event Output.
  * @param  NewState: new state of the Event output.
  *   This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
void GPIO_EventOutputCmd(FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  
  *(__IO uint32_t *) EVCR_EVOE_BB = (uint32_t)NewState;
}

/**
  * @brief  Changes the mapping of the specified pin.
  * @param  GPIO_Remap: selects the pin to remap.
  *   This parameter can be one of the following values:
  *     @arg GPIO_Remap_SPI1             : SPI1 Alternate Function mapping
  *     @arg GPIO_Remap_I2C1             : I2C1 Alternate Function mapping
  *     @arg GPIO_Remap_USART1           : USART1 Alternate Function mapping
  *     @arg GPIO_Remap_USART2           : USART2 Alternate Function mapping
  *     @arg GPIO_PartialRemap_USART3    : USART3 Partial Alternate Function mapping
  *     @arg GPIO_FullRemap_USART3       : USART3 Full Alternate Function mapping
  *     @arg GPIO_PartialRemap_TIM1      : TIM1 Partial Alternate Function mapping
  *     @arg GPIO_FullRemap_TIM1         : TIM1 Full Alternate Function mapping
  *     @arg GPIO_PartialRemap1_TIM2     : TIM2 Partial1 Alternate Function mapping
  *     @arg GPIO_PartialRemap2_TIM2     : TIM2 Partial2 Alternate Function mapping
  *     @arg GPIO_FullRemap_TIM2         : TIM2 Full Alternate Function mapping
  *     @arg GPIO_PartialRemap_TIM3      : TIM3 Partial Alternate Function mapping
  *     @arg GPIO_FullRemap_TIM3         : TIM3 Full Alternate Function mapping
  *     @arg GPIO_Remap_TIM4             : TIM4 Alternate Function mapping
  *     @arg GPIO_Remap1_CAN1            : CAN1 Alternate Function mapping
  *     @arg GPIO_Remap2_CAN1            : CAN1 Alternate Function mapping
  *     @arg GPIO_Remap_PD01             : PD01 Alternate Function mapping
  *     @arg GPIO_Remap_TIM5CH4_LSI      : LSI connected to TIM5 Channel4 input capture for calibration
  *     @arg GPIO_Remap_ADC1_ETRGINJ     : ADC1 External Trigger Injected Conversion remapping
  *     @arg GPIO_Remap_ADC1_ETRGREG     : ADC1 External Trigger Regular Conversion remapping
  *     @arg GPIO_Remap_ADC2_ETRGINJ     : ADC2 External Trigger Injected Conversion remapping
  *     @arg GPIO_Remap_ADC2_ETRGREG     : ADC2 External Trigger Regular Conversion remapping
  *     @arg GPIO_Remap_ETH              : Ethernet remapping (only for Connectivity line devices)
  *     @arg GPIO_Remap_CAN2             : CAN2 remapping (only for Connectivity line devices)
  *     @arg GPIO_Remap_SWJ_NoJTRST      : Full SWJ Enabled (JTAG-DP + SW-DP) but without JTRST
  *     @arg GPIO_Remap_SWJ_JTAGDisable  : JTAG-DP Disabled and SW-DP Enabled
  *     @arg GPIO_Remap_SWJ_Disable      : Full SWJ Disabled (JTAG-DP + SW-DP)
  *     @arg GPIO_Remap_SPI3             : SPI3/I2S3 Alternate Function mapping (only for Connectivity line devices)
  *                                        When the SPI3/I2S3 is remapped using this function, the SWJ is configured
  *                                        to Full SWJ Enabled (JTAG-DP + SW-DP) but without JTRST.   
  *     @arg GPIO_Remap_TIM2ITR1_PTP_SOF : Ethernet PTP output or USB OTG SOF (Start of Frame) connected
  *                                        to TIM2 Internal Trigger 1 for calibration (only for Connectivity line devices)
  *                                        If the GPIO_Remap_TIM2ITR1_PTP_SOF is enabled the TIM2 ITR1 is connected to 
  *                                        Ethernet PTP output. When Reset TIM2 ITR1 is connected to USB OTG SOF output.    
  *     @arg GPIO_Remap_PTP_PPS          : Ethernet MAC PPS_PTS output on PB05 (only for Connectivity line devices)
  *     @arg GPIO_Remap_TIM15            : TIM15 Alternate Function mapping (only for Value line devices)
  *     @arg GPIO_Remap_TIM16            : TIM16 Alternate Function mapping (only for Value line devices)
  *     @arg GPIO_Remap_TIM17            : TIM17 Alternate Function mapping (only for Value line devices)
  *     @arg GPIO_Remap_CEC              : CEC Alternate Function mapping (only for Value line devices)
  *     @arg GPIO_Remap_TIM1_DMA         : TIM1 DMA requests mapping (only for Value line devices)
  *     @arg GPIO_Remap_TIM9             : TIM9 Alternate Function mapping (only for XL-density devices)
  *     @arg GPIO_Remap_TIM10            : TIM10 Alternate Function mapping (only for XL-density devices)
  *     @arg GPIO_Remap_TIM11            : TIM11 Alternate Function mapping (only for XL-density devices)
  *     @arg GPIO_Remap_TIM13            : TIM13 Alternate Function mapping (only for High density Value line and XL-density devices)
  *     @arg GPIO_Remap_TIM14            : TIM14 Alternate Function mapping (only for High density Value line and XL-density devices)
  *     @arg GPIO_Remap_FSMC_NADV        : FSMC_NADV Alternate Function mapping (only for High density Value line and XL-density devices)
  *     @arg GPIO_Remap_TIM67_DAC_DMA    : TIM6/TIM7 and DAC DMA requests remapping (only for High density Value line devices)
  *     @arg GPIO_Remap_TIM12            : TIM12 Alternate Function mapping (only for High density Value line devices)
  *     @arg GPIO_Remap_MISC             : Miscellaneous Remap (DMA2 Channel5 Position and DAC Trigger remapping, 
  *                                        only for High density Value line devices)     
  * @param  NewState: new state of the port pin remapping.
  *   This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
void GPIO_PinRemapConfig(uint32_t GPIO_Remap, FunctionalState NewState)
{
  uint32_t tmp = 0x00, tmp1 = 0x00, tmpreg = 0x00, tmpmask = 0x00;

  /* Check the parameters */
  assert_param(IS_GPIO_REMAP(GPIO_Remap));
  assert_param(IS_FUNCTIONAL_STATE(NewState));  
  
  if((GPIO_Remap & 0x80000000) == 0x80000000)
  {
    tmpreg = AFIO->MAPR2;
  }
  else
  {
    tmpreg = AFIO->MAPR;
  }

  tmpmask = (GPIO_Remap & DBGAFR_POSITION_MASK) >> 0x10;
  tmp = GPIO_Remap & LSB_MASK;

  if ((GPIO_Remap & (DBGAFR_LOCATION_MASK | DBGAFR_NUMBITS_MASK)) == (DBGAFR_LOCATION_MASK | DBGAFR_NUMBITS_MASK))
  {
    tmpreg &= DBGAFR_SWJCFG_MASK;
    AFIO->MAPR &= DBGAFR_SWJCFG_MASK;
  }
  else if ((GPIO_Remap & DBGAFR_NUMBITS_MASK) == DBGAFR_NUMBITS_MASK)
  {
    tmp1 = ((uint32_t)0x03) << tmpmask;
    tmpreg &= ~tmp1;
    tmpreg |= ~DBGAFR_SWJCFG_MASK;
  }
  else
  {
    tmpreg &= ~(tmp << ((GPIO_Remap >> 0x15)*0x10));
    tmpreg |= ~DBGAFR_SWJCFG_MASK;
  }

  if (NewState != DISABLE)
  {
    tmpreg |= (tmp << ((GPIO_Remap >> 0x15)*0x10));
  }

  if((GPIO_Remap & 0x80000000) == 0x80000000)
  {
    AFIO->MAPR2 = tmpreg;
  }
  else
  {
    AFIO->MAPR = tmpreg;
  }  
}

/**
  * @brief  Selects the GPIO pin used as EXTI Line.
  * @param  GPIO_PortSource: selects the GPIO port to be used as source for EXTI lines.
  *   This parameter can be GPIO_PortSourceGPIOx where x can be (A..G).
  * @param  GPIO_PinSource: specifies the EXTI line to be configured.
  *   This parameter can be GPIO_PinSourcex where x can be (0..15).
  * @retval None
  */
void GPIO_EXTILineConfig(uint8_t GPIO_PortSource, uint8_t GPIO_PinSource)
{
  uint32_t tmp = 0x00;
  /* Check the parameters */
  assert_param(IS_GPIO_EXTI_PORT_SOURCE(GPIO_PortSource));
  assert_param(IS_GPIO_PIN_SOURCE(GPIO_PinSource));
  
  tmp = ((uint32_t)0x0F) << (0x04 * (GPIO_PinSource & (uint8_t)0x03));
  AFIO->EXTICR[GPIO_PinSource >> 0x02] &= ~tmp;
  AFIO->EXTICR[GPIO_PinSource >> 0x02] |= (((uint32_t)GPIO_PortSource) << (0x04 * (GPIO_PinSource & (uint8_t)0x03)));
}

/**
  * @brief  Selects the Ethernet media interface.
  * @note   This function applies only to STM32 Connectivity line devices.  
  * @param  GPIO_ETH_MediaInterface: specifies the Media Interface mode.
  *   This parameter can be one of the following values:
  *     @arg GPIO_ETH_MediaInterface_MII: MII mode
  *     @arg GPIO_ETH_MediaInterface_RMII: RMII mode    
  * @retval None
  */
void GPIO_ETH_MediaInterfaceConfig(uint32_t GPIO_ETH_MediaInterface) 
{ 
  assert_param(IS_GPIO_ETH_MEDIA_INTERFACE(GPIO_ETH_MediaInterface)); 

  /* Configure MII_RMII selection bit */ 
  *(__IO uint32_t *) MAPR_MII_RMII_SEL_BB = GPIO_ETH_MediaInterface; 
}
  
/**
  * @}
  */

/**
  * @}
  */

/**
  * @}
  */

/******************* (C) COPYRIGHT 2011 STMicroelectronics *****END OF FILE****/

开源库，软件库，组件库

环形缓冲库ring buffer：https://blog.csdn.net/qq_41854911/article/details/119299737

lwrb.h

/**
 * \file            lwrb.h
 * \brief           LwRB - Lightweight ring buffer
 */

/*
 * Copyright (c) 2020 Tilen MAJERLE
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * This file is part of LwRB - Lightweight ring buffer library.
 *
 * Author:          Tilen MAJERLE <tilen@majerle.eu>
 * Version:         v2.0.1
 */
#ifndef LWRB_HDR_H
#define LWRB_HDR_H

#include <string.h>
#include <stdint.h>

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */

/**
 * \defgroup        LWRB Lightweight ring buffer manager
 * \brief           Lightweight ring buffer manager
 * \{
 */

/**
 * \brief           Enable buffer structure pointer parameter as volatile
 * To use this feature, uncomment keyword below
 */
#define LWRB_VOLATILE                           /* volatile */

/**
 * \brief           Adds 2 magic words to make sure if memory is corrupted
 *                  application can detect wrong data pointer and maximum size
 */
#define LWRB_USE_MAGIC                      1

/**
 * \brief           Event type for buffer operations
 */
typedef enum {
    LWRB_EVT_READ,                              /*!< Read event */
    LWRB_EVT_WRITE,                             /*!< Write event */
    LWRB_EVT_RESET,                             /*!< Reset event */
} lwrb_evt_type_t;

/**
 * \brief           Buffer structure forward declaration
 */
struct lwrb;

/**
 * \brief           Event callback function type
 * \param[in]       buff: Buffer handle for event
 * \param[in]       evt: Event type
 * \param[in]       bp: Number of bytes written or read (when used), depends on event type
 */
typedef void (*lwrb_evt_fn)(LWRB_VOLATILE struct lwrb* buff, lwrb_evt_type_t evt, size_t bp);

/**
 * \brief           Buffer structure
 */
typedef struct lwrb {
#if LWRB_USE_MAGIC
    uint32_t magic1;                            /*!< Magic 1 word */
#endif /* LWRB_USE_MAGIC */
    uint8_t* buff;                              /*!< Pointer to buffer data.
                                                    Buffer is considered initialized when `buff != NULL` and `size > 0` */
    size_t size;                                /*!< Size of buffer data. Size of actual buffer is `1` byte less than value holds */
    size_t r;                                   /*!< Next read pointer. Buffer is considered empty when `r == w` and full when `w == r - 1` */
    size_t w;                                   /*!< Next write pointer. Buffer is considered empty when `r == w` and full when `w == r - 1` */
    lwrb_evt_fn evt_fn;                         /*!< Pointer to event callback function */
#if LWRB_USE_MAGIC
    uint32_t magic2;                            /*!< Magic 2 word */
#endif /* LWRB_USE_MAGIC */
} lwrb_t;

uint8_t     lwrb_init(LWRB_VOLATILE lwrb_t* buff, void* buffdata, size_t size);
uint8_t     lwrb_is_ready(LWRB_VOLATILE lwrb_t* buff);
void        lwrb_free(LWRB_VOLATILE lwrb_t* buff);
void        lwrb_reset(LWRB_VOLATILE lwrb_t* buff);
void        lwrb_set_evt_fn(LWRB_VOLATILE lwrb_t* buff, lwrb_evt_fn fn);

/* Read/Write functions */
size_t      lwrb_write(LWRB_VOLATILE lwrb_t* buff, const void* data, size_t btw);
size_t      lwrb_read(LWRB_VOLATILE lwrb_t* buff, void* data, size_t btr);
size_t      lwrb_peek(LWRB_VOLATILE lwrb_t* buff, size_t skip_count, void* data, size_t btp);

/* Buffer size information */
size_t      lwrb_get_free(LWRB_VOLATILE lwrb_t* buff);
size_t      lwrb_get_full(LWRB_VOLATILE lwrb_t* buff);

/* Read data block management */
void*       lwrb_get_linear_block_read_address(LWRB_VOLATILE lwrb_t* buff);
size_t      lwrb_get_linear_block_read_length(LWRB_VOLATILE lwrb_t* buff);
size_t      lwrb_skip(LWRB_VOLATILE lwrb_t* buff, size_t len);

/* Write data block management */
void*       lwrb_get_linear_block_write_address(LWRB_VOLATILE lwrb_t* buff);
size_t      lwrb_get_linear_block_write_length(LWRB_VOLATILE lwrb_t* buff);
size_t      lwrb_advance(LWRB_VOLATILE lwrb_t* buff, size_t len);

/**
 * \}
 */

#ifdef __cplusplus
}
#endif /* __cplusplus */

#endif /* LWRB_HDR_H */

lwrb.c

/**
 * \file            lwrb.c
 * \brief           Lightweight ring buffer
 */

/*
 * Copyright (c) 2020 Tilen MAJERLE
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * This file is part of LwRB - Lightweight ring buffer library.
 *
 * Author:          Tilen MAJERLE <tilen@majerle.eu>
 * Version:         v2.0.1
 */
#include "lwrb.h"

/* Memory set and copy functions */
#define BUF_MEMSET                      memset
#define BUF_MEMCPY                      memcpy

#define BUF_MAGIC1                      (0xDEADBEEF)
#define BUF_MAGIC2                      (~0xDEADBEEF)

#if LWRB_USE_MAGIC
#define BUF_IS_VALID(b)                 ((b) != NULL && (b)->magic1 == BUF_MAGIC1 && (b)->magic2 == BUF_MAGIC2 && (b)->buff != NULL && (b)->size > 0)
#else
#define BUF_IS_VALID(b)                 ((b) != NULL && (b)->buff != NULL && (b)->size > 0)
#endif /* LWRB_USE_MAGIC */
#define BUF_MIN(x, y)                   ((x) < (y) ? (x) : (y))
#define BUF_MAX(x, y)                   ((x) > (y) ? (x) : (y))
#define BUF_SEND_EVT(b, type, bp)       do { if ((b)->evt_fn != NULL) { (b)->evt_fn((b), (type), (bp)); } } while (0)

/**
 * \brief           Initialize buffer handle to default values with size and buffer data array
 * \param[in]       buff: Buffer handle
 * \param[in]       buffdata: Pointer to memory to use as buffer data
 * \param[in]       size: Size of `buffdata` in units of bytes
 *                      Maximum number of bytes buffer can hold is `size - 1`
 * \return          `1` on success, `0` otherwise
 */
uint8_t
lwrb_init(LWRB_VOLATILE lwrb_t* buff, void* buffdata, size_t size) {
    if (buff == NULL || buffdata == NULL || size == 0) {
        return 0;
    }

    BUF_MEMSET((void*)buff, 0x00, sizeof(*buff));

    buff->size = size;
    buff->buff = buffdata;

#if LWRB_USE_MAGIC
    buff->magic1 = BUF_MAGIC1;
    buff->magic2 = BUF_MAGIC2;
#endif /* LWRB_USE_MAGIC */

    return 1;
}

/**
 * \brief           Check if buff is initialized and ready to use
 * \param[in]       buff: Buffer handle
 * \return          `1` if ready, `0` otherwise
 */
uint8_t
lwrb_is_ready(LWRB_VOLATILE lwrb_t* buff) {
    return BUF_IS_VALID(buff);
}

/**
 * \brief           Free buffer memory
 * \note            Since implementation does not use dynamic allocation,
 *                  it just sets buffer handle to `NULL`
 * \param[in]       buff: Buffer handle
 */
void
lwrb_free(LWRB_VOLATILE lwrb_t* buff) {
    if (BUF_IS_VALID(buff)) {
        buff->buff = NULL;
    }
}

/**
 * \brief           Set event function callback for different buffer operations
 * \param[in]       buff: Buffer handle
 * \param[in]       evt_fn: Callback function
 */
void
lwrb_set_evt_fn(LWRB_VOLATILE lwrb_t* buff, lwrb_evt_fn evt_fn) {
    if (BUF_IS_VALID(buff)) {
        buff->evt_fn = evt_fn;
    }
}

/**
 * \brief           Write data to buffer.
 * Copies data from `data` array to buffer and marks buffer as full for maximum `btw` number of bytes
 *
 * \param[in]       buff: Buffer handle
 * \param[in]       data: Pointer to data to write into buffer
 * \param[in]       btw: Number of bytes to write
 * \return          Number of bytes written to buffer.
 *                      When returned value is less than `btw`, there was no enough memory available
 *                      to copy full data array
 */
size_t
lwrb_write(LWRB_VOLATILE lwrb_t* buff, const void* data, size_t btw) {
    size_t tocopy, free;
    const uint8_t* d = data;

    if (!BUF_IS_VALID(buff) || data == NULL || btw == 0) {
        return 0;
    }

    /* Calculate maximum number of bytes available to write */
    free = lwrb_get_free(buff);
    btw = BUF_MIN(free, btw);
    if (btw == 0) {
        return 0;
    }

    /* Step 1: Write data to linear part of buffer */
    tocopy = BUF_MIN(buff->size - buff->w, btw);
    BUF_MEMCPY(&buff->buff[buff->w], d, tocopy);
    buff->w += tocopy;
    btw -= tocopy;

    /* Step 2: Write data to beginning of buffer (overflow part) */
    if (btw > 0) {
        BUF_MEMCPY(buff->buff, &d[tocopy], btw);
        buff->w = btw;
    }

    /* Step 3: Check end of buffer */
    if (buff->w >= buff->size) {
        buff->w = 0;
    }
    BUF_SEND_EVT(buff, LWRB_EVT_WRITE, tocopy + btw);
    return tocopy + btw;
}

/**
 * \brief           Read data from buffer.
 * Copies data from buffer to `data` array and marks buffer as free for maximum `btr` number of bytes
 *
 * \param[in]       buff: Buffer handle
 * \param[out]      data: Pointer to output memory to copy buffer data to
 * \param[in]       btr: Number of bytes to read
 * \return          Number of bytes read and copied to data array
 */
size_t
lwrb_read(LWRB_VOLATILE lwrb_t* buff, void* data, size_t btr) {
    size_t tocopy, full;
    uint8_t* d = data;

    if (!BUF_IS_VALID(buff) || data == NULL || btr == 0) {
        return 0;
    }

    /* Calculate maximum number of bytes available to read */
    full = lwrb_get_full(buff);
    btr = BUF_MIN(full, btr);
    if (btr == 0) {
        return 0;
    }

    /* Step 1: Read data from linear part of buffer */
    tocopy = BUF_MIN(buff->size - buff->r, btr);
    BUF_MEMCPY(d, &buff->buff[buff->r], tocopy);
    buff->r += tocopy;
    btr -= tocopy;

    /* Step 2: Read data from beginning of buffer (overflow part) */
    if (btr > 0) {
        BUF_MEMCPY(&d[tocopy], buff->buff, btr);
        buff->r = btr;
    }

    /* Step 3: Check end of buffer */
    if (buff->r >= buff->size) {
        buff->r = 0;
    }
    BUF_SEND_EVT(buff, LWRB_EVT_READ, tocopy + btr);
    return tocopy + btr;
}

/**
 * \brief           Read from buffer without changing read pointer (peek only)
 * \param[in]       buff: Buffer handle
 * \param[in]       skip_count: Number of bytes to skip before reading data
 * \param[out]      data: Pointer to output memory to copy buffer data to
 * \param[in]       btp: Number of bytes to peek
 * \return          Number of bytes peeked and written to output array
 */
size_t
lwrb_peek(LWRB_VOLATILE lwrb_t* buff, size_t skip_count, void* data, size_t btp) {
    size_t full, tocopy, r;
    uint8_t* d = data;

    if (!BUF_IS_VALID(buff) || data == NULL || btp == 0) {
        return 0;
    }

    r = buff->r;

    /* Calculate maximum number of bytes available to read */
    full = lwrb_get_full(buff);

    /* Skip beginning of buffer */
    if (skip_count >= full) {
        return 0;
    }
    r += skip_count;
    full -= skip_count;
    if (r >= buff->size) {
        r -= buff->size;
    }

    /* Check maximum number of bytes available to read after skip */
    btp = BUF_MIN(full, btp);
    if (btp == 0) {
        return 0;
    }

    /* Step 1: Read data from linear part of buffer */
    tocopy = BUF_MIN(buff->size - r, btp);
    BUF_MEMCPY(d, &buff->buff[r], tocopy);
    btp -= tocopy;

    /* Step 2: Read data from beginning of buffer (overflow part) */
    if (btp > 0) {
        BUF_MEMCPY(&d[tocopy], buff->buff, btp);
    }
    return tocopy + btp;
}

/**
 * \brief           Get available size in buffer for write operation
 * \param[in]       buff: Buffer handle
 * \return          Number of free bytes in memory
 */
size_t
lwrb_get_free(LWRB_VOLATILE lwrb_t* buff) {
    size_t size, w, r;

    if (!BUF_IS_VALID(buff)) {
        return 0;
    }

    /* Use temporary values in case they are changed during operations */
    w = buff->w;
    r = buff->r;
    if (w == r) {
        size = buff->size;
    } else if (r > w) {
        size = r - w;
    } else {
        size = buff->size - (w - r);
    }

    /* Buffer free size is always 1 less than actual size */
    return size - 1;
}

/**
 * \brief           Get number of bytes currently available in buffer
 * \param[in]       buff: Buffer handle
 * \return          Number of bytes ready to be read
 */
size_t
lwrb_get_full(LWRB_VOLATILE lwrb_t* buff) {
    size_t w, r, size;

    if (!BUF_IS_VALID(buff)) {
        return 0;
    }

    /* Use temporary values in case they are changed during operations */
    w = buff->w;
    r = buff->r;
    if (w == r) {
        size = 0;
    } else if (w > r) {
        size = w - r;
    } else {
        size = buff->size - (r - w);
    }
    return size;
}

/**
 * \brief           Resets buffer to default values. Buffer size is not modified
 * \param[in]       buff: Buffer handle
 */
void
lwrb_reset(LWRB_VOLATILE lwrb_t* buff) {
    if (BUF_IS_VALID(buff)) {
        buff->w = 0;
        buff->r = 0;
        BUF_SEND_EVT(buff, LWRB_EVT_RESET, 0);
    }
}

/**
 * \brief           Get linear address for buffer for fast read
 * \param[in]       buff: Buffer handle
 * \return          Linear buffer start address
 */
void*
lwrb_get_linear_block_read_address(LWRB_VOLATILE lwrb_t* buff) {
    if (!BUF_IS_VALID(buff)) {
        return NULL;
    }
    return &buff->buff[buff->r];
}

/**
 * \brief           Get length of linear block address before it overflows for read operation
 * \param[in]       buff: Buffer handle
 * \return          Linear buffer size in units of bytes for read operation
 */
size_t
lwrb_get_linear_block_read_length(LWRB_VOLATILE lwrb_t* buff) {
    size_t w, r, len;

    if (!BUF_IS_VALID(buff)) {
        return 0;
    }

    /* Use temporary values in case they are changed during operations */
    w = buff->w;
    r = buff->r;
    if (w > r) {
        len = w - r;
    } else if (r > w) {
        len = buff->size - r;
    } else {
        len = 0;
    }
    return len;
}

/**
 * \brief           Skip (ignore; advance read pointer) buffer data
 * Marks data as read in the buffer and increases free memory for up to `len` bytes
 *
 * \note            Useful at the end of streaming transfer such as DMA
 * \param[in]       buff: Buffer handle
 * \param[in]       len: Number of bytes to skip and mark as read
 * \return          Number of bytes skipped
 */
size_t
lwrb_skip(LWRB_VOLATILE lwrb_t* buff, size_t len) {
    size_t full;

    if (!BUF_IS_VALID(buff) || len == 0) {
        return 0;
    }

    full = lwrb_get_full(buff);
    len = BUF_MIN(len, full);
    buff->r += len;
    if (buff->r >= buff->size) {
        buff->r -= buff->size;
    }
    BUF_SEND_EVT(buff, LWRB_EVT_READ, len);
    return len;
}

/**
 * \brief           Get linear address for buffer for fast read
 * \param[in]       buff: Buffer handle
 * \return          Linear buffer start address
 */
void*
lwrb_get_linear_block_write_address(LWRB_VOLATILE lwrb_t* buff) {
    if (!BUF_IS_VALID(buff)) {
        return NULL;
    }
    return &buff->buff[buff->w];
}

/**
 * \brief           Get length of linear block address before it overflows for write operation
 * \param[in]       buff: Buffer handle
 * \return          Linear buffer size in units of bytes for write operation
 */
size_t
lwrb_get_linear_block_write_length(LWRB_VOLATILE lwrb_t* buff) {
    size_t w, r, len;

    if (!BUF_IS_VALID(buff)) {
        return 0;
    }

    /* Use temporary values in case they are changed during operations */
    w = buff->w;
    r = buff->r;
    if (w >= r) {
        len = buff->size - w;
        /*
         * When read pointer is 0,
         * maximal length is one less as if too many bytes
         * are written, buffer would be considered empty again (r == w)
         */
        if (r == 0) {
            /*
             * Cannot overflow:
             * - If r is not 0, statement does not get called
             * - buff->size cannot be 0 and if r is 0, len is greater 0
             */
            --len;
        }
    } else {
        len = r - w - 1;
    }
    return len;
}

/**
 * \brief           Advance write pointer in the buffer.
 * Similar to skip function but modifies write pointer instead of read
 *
 * \note            Useful when hardware is writing to buffer and application needs to increase number
 *                      of bytes written to buffer by hardware
 * \param[in]       buff: Buffer handle
 * \param[in]       len: Number of bytes to advance
 * \return          Number of bytes advanced for write operation
 */
size_t
lwrb_advance(LWRB_VOLATILE lwrb_t* buff, size_t len) {
    size_t free;

    if (!BUF_IS_VALID(buff) || len == 0) {
        return 0;
    }

    free = lwrb_get_free(buff);
    len = BUF_MIN(len, free);
    buff->w += len;
    if (buff->w >= buff->size) {
        buff->w -= buff->size;
    }
    BUF_SEND_EVT(buff, LWRB_EVT_WRITE, len);
    return len;
}

标准库，系统库

可以参考这篇：c语言库函数总结

总结

• 每个模块都应该有一个主要的结构体，该结构体包含该模块的的基本属性；
• 宏定义可以出现在.h和.c里面，最终到底放在哪，要通过是否其他模块会使用该宏定义；
• 一般情况下，该模块中的所有函数的第一个参数都是基本结构体的指针，一定不要写那种直接操作全局变量，不带参数的函数；
• 每个函数一定要做参数检查，做好防御编程，日志记录，单元测试；