GPIO指的是通用输入输出。
根据数据手册中列出的每个I/O端口的特定硬件特征， GPIO端口的每个位可以由软件分别配置
成多种模式。
─ 输入浮空
─ 输入上拉
─ 输入下拉
─ 模拟输入
─ 开漏输出
─ 推挽式输出
─ 推挽式复用功能
─ 开漏复用功能
我们来看看固件库是如何给我们封装的函数。
在固件库的封装上来看，也不是那么繁琐的.
stm32f10x_gpio.h，加上注释也就只有300多行，里面都是一些对port、pin的宏定义、封装结构体。
/**
* @brief GPIO Init s tructure 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;
//定义一个结构体，用typedef定义了一个结构体，GPIO_InitTypeDef，包含
{uint16_t GPIO_Pin; //用户指定一个pin引脚
#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 */
GPIOSpeed_TypeDef GPIO_Speed; //GPIOSpeed_TypeDef 枚举类型的GPIO_Speed，
用typedef定义了了枚举类型
typedef enum
{
GPIO_Speed_10MHz = 1,
GPIO_Speed_2MHz,
GPIO_Speed_50MHz
}GPIOSpeed_TypeDef;
GPIOMode_TypeDef GPIO_Mode; //GPIOMode_TypeDef 枚举类型的GPIO_Mode，
用typedef定义了了枚举类型
typedef enum
{
GPIO_Mode_AIN = 0x0, //模拟输入
GPIO_Mode_IN_FLOATING = 0x04, //浮空输入
GPIO_Mode_IPD = 0x28, //下拉输入
GPIO_Mode_IPU = 0x48, //上拉输入
GPIO_Mode_Out_OD = 0x14, //开漏输出
GPIO_Mode_Out_PP = 0x10, //推挽输出
GPIO_Mode_AF_OD = 0x1C, //复用开漏输出
GPIO_Mode_AF_PP = 0x18 //复用推挽输出
}GPIOMode_TypeDef;
还有一些类似的定义...
接下来随stm32f10x_gpio.c
在前面都是一样的方法:进行位带定义
/* ------------ 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))
函数:
/**
* @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){...} //GPIO初始化
/**
* @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){...} //位置1
/**
* @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){...} //复位 置0
.....还有很多函数，也有功能重复的，常用的其实也就那么几个，等用到的时候在添加吧...
中断
/**
* @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
*/
//中断配置,, 1.GPIO_PortSourceGPIOx where x can be (A..G).2.GPIO_PinSourcex where x can be (0..15).
void GPIO_EXTILineConfig(uint8_t GPIO_PortSource, uint8_t GPIO_PinSource){...}
还有AFIO，复用端口函数
void GPIO_PinRemapConfig(uint32_t GPIO_Remap, FunctionalState NewState){} //复用映射，注意要同时开启AFIO时钟。