【STM32】GPIO功能复用

程序员文章站 2024-02-22 20:34:58

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00. 目录

文章目录

00. 目录
01. GPIO复用概述
02. 寄存器描述
03. 类型
04. 函数
05. 参考示例
06. 附录
07. 声明

01. GPIO复用概述

STM32F4 有很多的内置外设，这些外设的外部引脚都是与 GPIO 复用的。也就是说，一个 GPIO如果可以复用为内置外设的功能引脚，那么当这个 GPIO 作为内置外设使用的时候，就叫做复用。

STM32F4 系列微控制器 IO 引脚通过一个复用器连接到内置外设或模块。该复用器一次只允许一个外设的复用功能（AF）连接到对应的 IO 口。这样可以确保共用同一个 IO 引脚的外设之间不会发生冲突。

每个 IO 引脚都有一个复用器，该复用器采用 16 路复用功能输入（AF0 到 AF15），可通过GPIOx_AFRL(针对引脚 0-7)和 GPIOx_AFRH（针对引脚 8-15）寄存器对这些输入进行配置，每四位控制一路复用

1）完成复位后，所有 IO 都会连接到系统的复用功能 0（AF0）。
2）外设的复用功能映射到 AF1 到 AF13。
3）Cortex-M4 EVENTOUT 映射到 AF15。
【STM32】GPIO功能复用

02. 寄存器描述

探索者 STM32F407 开发板的原理图上 PC11 的原理图如图所示：
【STM32】GPIO功能复用

PC11 可以作为 SPI3_MISO/U3_RX/U4_RX/SDIO_D3/DCMI_D4/I2S3ext_SD等复用功能输出，这么多复用功能，如果这些外设都开启了，那么对 STM32F1 来说，那就可能乱套了，外设之间可互相干扰，但是 STM32F4，由于有复用功能选择功能，可以让 PC11 仅连接到某个特定的外设，因此不存在互相干扰的情况。

GPIO 复用功能低位寄存器 (GPIOx_AFRL) (x = A…I)
GPIO alternate function low register
偏移地址：0x20
复位值：0x0000 0000
【STM32】GPIO功能复用

GPIO 复用功能高位寄存器 (GPIOx_AFRH) (x = A…I)
GPIO alternate function high register
偏移地址：0x24
复位值：0x0000 0000
【STM32】GPIO功能复用

在微控制器完成复位后，所有 IO 口都会连接到系统复用功能 0（AF0）。这里大家需要注意，对于系统复用功能 AF0，我们将 IO 口连接到 AF0 之后，还要根据所用功能进行配置：

JTAG/SWD:在器件复位之后，会将这些功能引脚指定为专用引脚。也就是说，这些引脚在复位后默认就是 JTAG/SWD 功能。如果我们要作为 GPIO 来使用，就需要对对应的 IO口复用器进行配置。
RTC_REFIN:此引脚在系统复位之后要使用的话要配置为浮空输入模式。
MCO1 和 MCO2：这些引脚在系统复位之后要使用的话要配置为复用功能模式。

03. 类型

复用功能相关宏

/** 
  * @brief   AF 0 selection  
  */ 
#define GPIO_AF_RTC_50Hz      ((uint8_t)0x00)  /* RTC_50Hz Alternate Function mapping */
#define GPIO_AF_MCO           ((uint8_t)0x00)  /* MCO (MCO1 and MCO2) Alternate Function mapping */
#define GPIO_AF_TAMPER        ((uint8_t)0x00)  /* TAMPER (TAMPER_1 and TAMPER_2) Alternate Function mapping */
#define GPIO_AF_SWJ           ((uint8_t)0x00)  /* SWJ (SWD and JTAG) Alternate Function mapping */
#define GPIO_AF_TRACE         ((uint8_t)0x00)  /* TRACE Alternate Function mapping */
#if defined(STM32F446xx)
#define GPIO_AF0_TIM2         ((uint8_t)0x00)  /* TIM2 Alternate Function mapping */
#endif /* STM32F446xx */

/** 
  * @brief   AF 1 selection  
  */ 
#define GPIO_AF_TIM1          ((uint8_t)0x01)  /* TIM1 Alternate Function mapping */
#define GPIO_AF_TIM2          ((uint8_t)0x01)  /* TIM2 Alternate Function mapping */
#if defined(STM32F410xx) || defined(STM32F413_423xx)
#define GPIO_AF_LPTIM         ((uint8_t)0x01)  /* LPTIM Alternate Function mapping */
#endif /* STM32F410xx || STM32F413_423xx */
/** 
  * @brief   AF 2 selection  
  */ 
#define GPIO_AF_TIM3          ((uint8_t)0x02)  /* TIM3 Alternate Function mapping */
#define GPIO_AF_TIM4          ((uint8_t)0x02)  /* TIM4 Alternate Function mapping */
#define GPIO_AF_TIM5          ((uint8_t)0x02)  /* TIM5 Alternate Function mapping */

/** 
  * @brief   AF 3 selection  
  */ 
#define GPIO_AF_TIM8          ((uint8_t)0x03)  /* TIM8 Alternate Function mapping */
#define GPIO_AF_TIM9          ((uint8_t)0x03)  /* TIM9 Alternate Function mapping */
#define GPIO_AF_TIM10         ((uint8_t)0x03)  /* TIM10 Alternate Function mapping */
#define GPIO_AF_TIM11         ((uint8_t)0x03)  /* TIM11 Alternate Function mapping */
#if defined(STM32F446xx)
#define GPIO_AF3_CEC          ((uint8_t)0x03)  /* CEC Alternate Function mapping */
#endif /* STM32F446xx */
#if defined(STM32F413_423xx)
#define GPIO_AF3_DFSDM2       ((uint8_t)0x03)  /* DFSDM2 Alternate Function mapping */
#endif /* STM32F413_423xx */
/** 
  * @brief   AF 4 selection  
  */ 
#define GPIO_AF_I2C1          ((uint8_t)0x04)  /* I2C1 Alternate Function mapping */
#define GPIO_AF_I2C2          ((uint8_t)0x04)  /* I2C2 Alternate Function mapping */
#define GPIO_AF_I2C3          ((uint8_t)0x04)  /* I2C3 Alternate Function mapping */
#if defined(STM32F446xx)
#define GPIO_AF4_CEC          ((uint8_t)0x04)  /* CEC Alternate Function mapping */
#endif /* STM32F446xx */
#if defined(STM32F410xx) || defined(STM32F412xG) || defined(STM32F413_423xx) || defined(STM32F446xx)
#define GPIO_AF_FMPI2C        ((uint8_t)0x04)  /* FMPI2C Alternate Function mapping */
#endif /* STM32F410xx || STM32F446xx */

/** 
  * @brief   AF 5 selection  
  */ 
#define GPIO_AF_SPI1          ((uint8_t)0x05)  /* SPI1/I2S1 Alternate Function mapping */
#define GPIO_AF_SPI2          ((uint8_t)0x05)  /* SPI2/I2S2 Alternate Function mapping */
#define GPIO_AF5_SPI3         ((uint8_t)0x05)  /* SPI3/I2S3 Alternate Function mapping (Only for STM32F411xE and STM32F413_423xx Devices) */
#define GPIO_AF_SPI4          ((uint8_t)0x05)  /* SPI4/I2S4 Alternate Function mapping */
#define GPIO_AF_SPI5          ((uint8_t)0x05)  /* SPI5 Alternate Function mapping      */
#define GPIO_AF_SPI6          ((uint8_t)0x05)  /* SPI6 Alternate Function mapping      */

/** 
  * @brief   AF 6 selection  
  */ 
#define GPIO_AF_SPI3          ((uint8_t)0x06)  /* SPI3/I2S3 Alternate Function mapping */
#define GPIO_AF6_SPI1         ((uint8_t)0x06)  /* SPI1 Alternate Function mapping (Only for STM32F410xx Devices) */
#define GPIO_AF6_SPI2         ((uint8_t)0x06)  /* SPI2 Alternate Function mapping (Only for STM32F410xx/STM32F411xE Devices) */
#define GPIO_AF6_SPI4         ((uint8_t)0x06)  /* SPI4 Alternate Function mapping (Only for STM32F411xE Devices) */
#define GPIO_AF6_SPI5         ((uint8_t)0x06)  /* SPI5 Alternate Function mapping (Only for STM32F410xx/STM32F411xE Devices) */
#define GPIO_AF_SAI1          ((uint8_t)0x06)  /* SAI1 Alternate Function mapping      */
#define GPIO_AF_I2S2ext       ((uint8_t)0x06)  /* I2S2ext_SD Alternate Function mapping (only for STM32F412xG and STM32F413_423xx Devices) */
#if defined(STM32F412xG) || defined(STM32F413_423xx)
#define GPIO_AF6_DFSDM1       ((uint8_t)0x06)  /* DFSDM1 Alternate Function mapping */
#endif /* STM32F412xG || STM32F413_423xx */
#if defined(STM32F413_423xx)
#define GPIO_AF6_DFSDM2       ((uint8_t)0x06)  /* DFSDM2 Alternate Function mapping */
#endif /* STM32F413_423xx */

/** 
  * @brief   AF 7 selection  
  */ 
#define GPIO_AF_USART1         ((uint8_t)0x07)  /* USART1 Alternate Function mapping  */
#define GPIO_AF_USART2         ((uint8_t)0x07)  /* USART2 Alternate Function mapping  */
#define GPIO_AF_USART3         ((uint8_t)0x07)  /* USART3 Alternate Function mapping  */
#define GPIO_AF7_SPI3          ((uint8_t)0x07)  /* SPI3/I2S3ext Alternate Function mapping */
#if defined(STM32F413_423xx)
#define GPIO_AF7_DFSDM2        ((uint8_t)0x07)  /* DFSDM2 Alternate Function mapping     */
#define GPIO_AF7_SAI1          ((uint8_t)0x07)  /* SAI1 Alternate Function mapping       */
#endif /* STM32F413_423xx */

/** 
  * @brief   AF 7 selection Legacy 
  */ 
#define GPIO_AF_I2S3ext   GPIO_AF7_SPI3

/** 
  * @brief   AF 8 selection  
  */ 
#define GPIO_AF_UART4         ((uint8_t)0x08)  /* UART4 Alternate Function mapping  */
#define GPIO_AF_UART5         ((uint8_t)0x08)  /* UART5 Alternate Function mapping  */
#define GPIO_AF_USART6        ((uint8_t)0x08)  /* USART6 Alternate Function mapping */
#define GPIO_AF_UART7         ((uint8_t)0x08)  /* UART7 Alternate Function mapping  */
#define GPIO_AF_UART8         ((uint8_t)0x08)  /* UART8 Alternate Function mapping  */
#if defined(STM32F412xG) || defined(STM32F413_423xx)
#define GPIO_AF8_USART3        ((uint8_t)0x08)  /* USART3 Alternate Function mapping */
#define GPIO_AF8_DFSDM1        ((uint8_t)0x08)  /* DFSDM Alternate Function mapping  */
#define GPIO_AF8_CAN1          ((uint8_t)0x08)  /* CAN1 Alternate Function mapping   */
#endif /* STM32F412xG || STM32F413_423xx */
#if defined(STM32F446xx)
#define GPIO_AF8_SAI2          ((uint8_t)0x08)  /* SAI2 Alternate Function mapping */
#define GPIO_AF_SPDIF         ((uint8_t)0x08)   /* SPDIF Alternate Function mapping */
#endif /* STM32F446xx */

/** 
  * @brief   AF 9 selection 
  */ 
#define GPIO_AF_CAN1          ((uint8_t)0x09)  /* CAN1 Alternate Function mapping  */
#define GPIO_AF_CAN2          ((uint8_t)0x09)  /* CAN2 Alternate Function mapping  */
#define GPIO_AF_TIM12         ((uint8_t)0x09)  /* TIM12 Alternate Function mapping */
#define GPIO_AF_TIM13         ((uint8_t)0x09)  /* TIM13 Alternate Function mapping */
#define GPIO_AF_TIM14         ((uint8_t)0x09)  /* TIM14 Alternate Function mapping */
#define GPIO_AF9_I2C2         ((uint8_t)0x09)  /* I2C2 Alternate Function mapping (Only for STM32F401xx/STM32F410xx/STM32F411xE/STM32F412xG/STM32F413_423xx Devices) */
#define GPIO_AF9_I2C3         ((uint8_t)0x09)  /* I2C3 Alternate Function mapping (Only for STM32F401xx/STM32F411xE/STM32F412xG and STM32F413_423xx Devices) */
#if defined(STM32F446xx)
#define GPIO_AF9_SAI2         ((uint8_t)0x09)  /* SAI2 Alternate Function mapping */
#endif /* STM32F446xx */
#define GPIO_AF9_LTDC         ((uint8_t)0x09)  /* LTDC Alternate Function mapping */
#if defined(STM32F412xG) || defined(STM32F413_423xx) || defined(STM32F446xx) || defined(STM32F469_479xx)
#define GPIO_AF9_QUADSPI      ((uint8_t)0x09)  /* QuadSPI Alternate Function mapping */
#endif /* STM32F412xG || STM32F413_423xx || STM32F446xx || STM32F469_479xx */
#if defined(STM32F410xx) || defined(STM32F412xG) || defined(STM32F413_423xx)
#define GPIO_AF9_FMPI2C       ((uint8_t)0x09)  /* FMPI2C Alternate Function mapping (Only for STM32F410xx Devices) */
#endif /* STM32F410xx || STM32F412xG || STM32F413_423xx */

/** 
  * @brief   AF 10 selection  
  */ 
#define GPIO_AF_OTG_FS         ((uint8_t)0xA)  /* OTG_FS Alternate Function mapping */
#define GPIO_AF_OTG_HS         ((uint8_t)0xA)  /* OTG_HS Alternate Function mapping */
#if defined(STM32F446xx)
#define GPIO_AF10_SAI2         ((uint8_t)0x0A)  /* SAI2 Alternate Function mapping */
#endif /* STM32F446xx */
#if defined(STM32F412xG) || defined(STM32F413_423xx) || defined(STM32F446xx) || defined(STM32F469_479xx)
#define GPIO_AF10_QUADSPI      ((uint8_t)0x0A)  /* QuadSPI Alternate Function mapping */
#endif /* STM32F412xG || STM32F413_423xx || STM32F446xx || STM32F469_479xx */
#if defined(STM32F412xG) || defined(STM32F413_423xx)
#define GPIO_AF10_FMC           ((uint8_t)0xA)  /* FMC Alternate Function mapping    */
#define GPIO_AF10_DFSDM1         ((uint8_t)0xA) /* DFSDM Alternate Function mapping  */
#endif /* STM32F412xG || STM32F413_423xx */
#if defined(STM32F413_423xx)
#define GPIO_AF10_DFSDM2        ((uint8_t)0x0A)  /* DFSDM2 Alternate Function mapping */
#define GPIO_AF10_SAI1          ((uint8_t)0x0A)  /* SAI1 Alternate Function mapping   */
#endif /* STM32F413_423xx */
/** 
  * @brief   AF 11 selection  
  */ 
#define GPIO_AF_ETH             ((uint8_t)0x0B)  /* ETHERNET Alternate Function mapping */
#if defined(STM32F413_423xx)
#define GPIO_AF11_UART4         ((uint8_t)0x0B)  /* UART4 Alternate Function mapping  */
#define GPIO_AF11_UART5         ((uint8_t)0x0B)  /* UART5 Alternate Function mapping  */
#define GPIO_AF11_UART9         ((uint8_t)0x0B)  /* UART9 Alternate Function mapping  */
#define GPIO_AF11_UART10        ((uint8_t)0x0B)  /* UART10 Alternate Function mapping */
#define GPIO_AF11_CAN3          ((uint8_t)0x0B)  /* CAN3 Alternate Function mapping   */
#endif /* STM32F413_423xx */

/** 
  * @brief   AF 12 selection  
  */ 
#if defined(STM32F40_41xxx) || defined(STM32F412xG) || defined(STM32F413_423xx)
#define GPIO_AF_FSMC             ((uint8_t)0xC)  /* FSMC Alternate Function mapping                     */
#endif /* STM32F40_41xxx || STM32F412xG || STM32F413_423xx */

#if defined(STM32F427_437xx) || defined(STM32F429_439xx) || defined(STM32F446xx) || defined(STM32F469_479xx)
#define GPIO_AF_FMC              ((uint8_t)0xC)  /* FMC Alternate Function mapping                      */
#endif /* STM32F427_437xx || STM32F429_439xx || STM32F446xx || STM32F469_479xx */

#define GPIO_AF_OTG_HS_FS        ((uint8_t)0xC)  /* OTG HS configured in FS, Alternate Function mapping */
#define GPIO_AF_SDIO             ((uint8_t)0xC)  /* SDIO Alternate Function mapping                     */

/** 
  * @brief   AF 13 selection  
  */ 
#define GPIO_AF_DCMI          ((uint8_t)0x0D)  /* DCMI Alternate Function mapping */
#if defined(STM32F469_479xx)
#define GPIO_AF_DSI           ((uint8_t)0x0D)  /* DSI Alternate Function mapping */
#endif /* STM32F469_479xx */
/** 
  * @brief   AF 14 selection  
  */
#define GPIO_AF_LTDC          ((uint8_t)0x0E)  /* LCD-TFT Alternate Function mapping */
#if defined(STM32F413_423xx)
#define GPIO_AF14_RNG         ((uint8_t)0x0E)  /* RNG Alternate Function mapping  */
#endif /* STM32F413_423xx */

/** 
  * @brief   AF 15 selection  
  */ 
#define GPIO_AF_EVENTOUT      ((uint8_t)0x0F)  /* EVENTOUT Alternate Function mapping */

#define IS_GPIO_AF(AF)   (((AF) == GPIO_AF_RTC_50Hz)  || ((AF) == GPIO_AF_TIM14)     || \
                          ((AF) == GPIO_AF_MCO)       || ((AF) == GPIO_AF_TAMPER)    || \
                          ((AF) == GPIO_AF_SWJ)       || ((AF) == GPIO_AF_TRACE)     || \
                          ((AF) == GPIO_AF_TIM1)      || ((AF) == GPIO_AF_TIM2)      || \
                          ((AF) == GPIO_AF_TIM3)      || ((AF) == GPIO_AF_TIM4)      || \
                          ((AF) == GPIO_AF_TIM5)      || ((AF) == GPIO_AF_TIM8)      || \
                          ((AF) == GPIO_AF_I2C1)      || ((AF) == GPIO_AF_I2C2)      || \
                          ((AF) == GPIO_AF_I2C3)      || ((AF) == GPIO_AF_SPI1)      || \
                          ((AF) == GPIO_AF_SPI2)      || ((AF) == GPIO_AF_TIM13)     || \
                          ((AF) == GPIO_AF_SPI3)      || ((AF) == GPIO_AF_TIM14)     || \
                          ((AF) == GPIO_AF_USART1)    || ((AF) == GPIO_AF_USART2)    || \
                          ((AF) == GPIO_AF_USART3)    || ((AF) == GPIO_AF_UART4)     || \
                          ((AF) == GPIO_AF_UART5)     || ((AF) == GPIO_AF_USART6)    || \
                          ((AF) == GPIO_AF_CAN1)      || ((AF) == GPIO_AF_CAN2)      || \
                          ((AF) == GPIO_AF_OTG_FS)    || ((AF) == GPIO_AF_OTG_HS)    || \
                          ((AF) == GPIO_AF_ETH)       || ((AF) == GPIO_AF_OTG_HS_FS) || \
                          ((AF) == GPIO_AF_SDIO)      || ((AF) == GPIO_AF_DCMI)      || \
                          ((AF) == GPIO_AF_EVENTOUT)  || ((AF) == GPIO_AF_FSMC))
#endif /* STM32F40_41xxx */

04. 函数

GPIO复用功能函数

/* GPIO Alternate functions configuration function ****************************/
void GPIO_PinAFConfig(GPIO_TypeDef* GPIOx, uint16_t GPIO_PinSource, uint8_t GPIO_AF);

05. 参考示例

串口配置

/*GPIOA9 与 GPIOA10 初始化*/
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;// 复用功能
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;//速度 50MHz
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; //推挽复用输出
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; //上拉
GPIO_Init(GPIOA,&GPIO_InitStructure); //初始化 PA9，PA10

/*PA9 连接 AF7，复用为 USART1_TX */
GPIO_PinAFConfig(GPIOA,GPIO_PinSource9,GPIO_AF_USART1);
/* PA10 连接 AF7,复用为 USART1_RX*/
GPIO_PinAFConfig(GPIOA,GPIO_PinSource10,GPIO_AF_USART1);

06. 附录

6.1 【STM32】STM32系列教程汇总

网址：【STM32】STM32系列教程汇总

07. 声明

该教程参考了正点原子的《STM32 F4 开发指南》

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【STM32】GPIO功能复用

00. 目录

文章目录

01. GPIO复用概述

02. 寄存器描述

03. 类型

04. 函数

05. 参考示例

06. 附录

07. 声明

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