1.函数声明(stm32f10x_gpio.h)
void GPIO_Init(GPIO_TypeDef* GPIOx, GPIO_InitTypeDef* GPIO_InitStruct);
2.参数
GPIOx对应端口寄存器影像地址，GPIO_InitStruct为参数结构体。GPIO_Init()完成了GPIO_InitStruct中的参数信息，填充到GPIOx中。
a.GPIO_TypeDef* GPIOx
typedef struct { __IO uint32_t CRL;
__IO uint32_t CRH; __IO uint32_t IDR; __IO uint32_t ODR; __IO uint32_t BSRR; __IO uint32_t BRR; __IO uint32_t LCKR; } GPIO_TypeDef;
GPIOx为指向GPIO_TypeDef类型的指针，与存储器影像地址对应。例如GPIOF
#define GPIOF ((GPIO_TypeDef *) GPIOF_BASE) //stm3210x.h #define GPIOF_BASE (APB2PERIPH_BASE + 0x1C00) //stm3210x.h #define APB2PERIPH_BASE (PERIPH_BASE + 0x10000) #define PERIPH_BASE ((uint32_t)0x40000000)
可知GPIOF = 0x40011C00,查stm32f10xx手册即为存储器影像地址。
b.GPIO_InitTypeDef* GPIO_InitStruct
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;
GPIO_Pin的16位分别对应端口GPIOx的0~15引脚选择信息。0代表不配置，1代表进行配置。例如GPIO_Pin_0，即Pinx0被选择，需配置。
#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 */
GPIO_Speed设置引脚速度，引脚速度又称输出驱动电路的响应速度，即一个驱动电路可以不失真地通过信号的最大频率。GPIO_Pin中选择的的引脚，速度将都被设置为该速度。
typedef enum { GPIO_Speed_10MHz = 1, GPIO_Speed_2MHz, GPIO_Speed_50MHz }GPIOSpeed_TypeDef;
GPIO_Mode为配置模式信息，使用一字节存储，格式为：保留[7],上拉(10)下拉(01)[6:5],输出(1)输入(0)模式[4],CNFy[3:2],MODEy[1:0]。速度信息已存在GPIO_Speed中，在GPIO_Mode中MODEy[1:0] = 00。
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;
3.定义(stm32f10x_gpio.c)
/** * @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); //保存原引脚速度 if ((((uint32_t)GPIO_InitStruct->GPIO_Mode) & ((uint32_t)0x10)) != 0x00) //配置为输出模式，需设置引脚速度 { /* 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) //有引脚需要进行配置 { tmpreg = GPIOx->CRL; //保存原CRL信息 for (pinpos = 0x00; pinpos < 0x08; pinpos++) //遍历端口x配置位（0...7) { pos = ((uint32_t)0x01) << pinpos; //当前位 /* Get the port pins position */ currentpin = (GPIO_InitStruct->GPIO_Pin) & pos; //当前位是否被选择 if (currentpin == pos) //是，配置当前位 { pos = pinpos << 2; //配置位*4，即CRL中位置MODE-pinpos[0] /* Clear the corresponding low control register bits */ pinmask = ((uint32_t)0x0F) << pos; //清原CRL的CNF-pinpos[1:0],MODE-pinpos[1:0] tmpreg &= ~pinmask; /* Write the mode configuration in the corresponding bits */ tmpreg |= (currentmode << pos); //设置速度 /* Reset the corresponding ODR bit */ if (GPIO_InitStruct->GPIO_Mode == GPIO_Mode_IPD) //输入下拉模式，PxODR配置为0 { GPIOx->BRR = (((uint32_t)0x01) << pinpos); } else { /* Set the corresponding ODR bit */ if (GPIO_InitStruct->GPIO_Mode == GPIO_Mode_IPU) //输入上拉模式，PxODR配置为1 { GPIOx->BSRR = (((uint32_t)0x01) << pinpos); } } } } GPIOx->CRL = tmpreg; //配置CRL } /*---------------------------- 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; }
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