STM32F4xxx的程序中GPIO_PinAFConfig 是什么用的？

Question

如题所述

Answer 1

这是F4系列中指定gpio复用功能的函数。在单片机中经常一个引脚存在多个功能，如下图：

引脚41同时具有PA8、SCL3、T1CH1三种功能，假如我要使用TIM1定时器功能的话，那么在配置gpio的输出模式的时候就要配置为复用功能AF，每个AF在又存在多个选择：

根据上图可以查到AF2与TIM1相对应，那么我们就可以这样连接：

GPIO_PinAFConfig(PWM_GPIO_PORT, GPIO_PinSource8, GPIO_AF_TIM1);

Answer 2

您好，STM32F4学习笔记之GPIO(使用固件库)
1.使能GPIO的AHB时钟，使用函数： RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOx, ENABLE);

2.配置GPIO工作模式用GPIO_Init()函数
数据类型说明
typedef struct
{
uint32_t GPIO_Pin; //引脚配置
GPIOMode_TypeDef GPIO_Mode; //GPIO_Mode_IN(输入),GPIO_Mode_OUT（输出）,GPIO_Mode_AF（备用）,GPIO_Mode_AN（模拟）
GPIOSpeed_TypeDef GPIO_Speed;// GPIO_Speed_2MHz，GPIO_Speed_25MHz，GPIO_Speed_50MHz，GPIO_Speed_100MHz

GPIOOType_TypeDef GPIO_OType; // GPIO_OType_PP（推挽）,GPIO_OType_OD（开漏）
GPIOPuPd_TypeDef GPIO_PuPd; GPIO_PuPd_NOPULL（无），GPIO_PuPd_UP（上拉），GPIO_PuPd_DOWN（下拉）
}GPIO_InitTypeDef;
3.备用功能配置（除ADC和DAC外的所有非GPIO功能），使用函数

void GPIO_PinAFConfig(GPIO_TypeDef* GPIOx, uint16_t GPIO_PinSource, uint8_t GPIO_AF)
* This GPIO_AF can be one of the following values:
* @arg GPIO_AF_RTC_50Hz: Connect RTC_50Hz pin to AF0 (default after reset)
* @arg GPIO_AF_MCO: Connect MCO pin (MCO1 and MCO2) to AF0 (default after reset)
* @arg GPIO_AF_TAMPER: Connect TAMPER pins (TAMPER_1 and TAMPER_2) to AF0 (default after reset)
* @arg GPIO_AF_SWJ: Connect SWJ pins (SWD and JTAG)to AF0 (default after reset)
* @arg GPIO_AF_TRACE: Connect TRACE pins to AF0 (default after reset)
* @arg GPIO_AF_TIM1: Connect TIM1 pins to AF1
* @arg GPIO_AF_TIM2: Connect TIM2 pins to AF1
* @arg GPIO_AF_TIM3: Connect TIM3 pins to AF2
* @arg GPIO_AF_TIM4: Connect TIM4 pins to AF2
* @arg GPIO_AF_TIM5: Connect TIM5 pins to AF2
* @arg GPIO_AF_TIM8: Connect TIM8 pins to AF3
* @arg GPIO_AF_TIM9: Connect TIM9 pins to AF3
* @arg GPIO_AF_TIM10: Connect TIM10 pins to AF3
* @arg GPIO_AF_TIM11: Connect TIM11 pins to AF3
* @arg GPIO_AF_I2C1: Connect I2C1 pins to AF4
* @arg GPIO_AF_I2C2: Connect I2C2 pins to AF4
* @arg GPIO_AF_I2C3: Connect I2C3 pins to AF4
* @arg GPIO_AF_SPI1: Connect SPI1 pins to AF5
* @arg GPIO_AF_SPI2: Connect SPI2/I2S2 pins to AF5
* @arg GPIO_AF_SPI3: Connect SPI3/I2S3 pins to AF6
* @arg GPIO_AF_I2S3ext: Connect I2S3ext pins to AF7
* @arg GPIO_AF_USART1: Connect USART1 pins to AF7
* @arg GPIO_AF_USART2: Connect USART2 pins to AF7
* @arg GPIO_AF_USART3: Connect USART3 pins to AF7
* @arg GPIO_AF_UART4: Connect UART4 pins to AF8
* @arg GPIO_AF_UART5: Connect UART5 pins to AF8
* @arg GPIO_AF_USART6: Connect USART6 pins to AF8
* @arg GPIO_AF_CAN1: Connect CAN1 pins to AF9
* @arg GPIO_AF_CAN2: Connect CAN2 pins to AF9
* @arg GPIO_AF_TIM12: Connect TIM12 pins to AF9
* @arg GPIO_AF_TIM13: Connect TIM13 pins to AF9
* @arg GPIO_AF_TIM14: Connect TIM14 pins to AF9
* @arg GPIO_AF_OTG_FS: Connect OTG_FS pins to AF10
* @arg GPIO_AF_OTG_HS: Connect OTG_HS pins to AF10
* @arg GPIO_AF_ETH: Connect ETHERNET pins to AF11
* @arg GPIO_AF_FSMC: Connect FSMC pins to AF12
* @arg GPIO_AF_OTG_HS_FS: Connect OTG HS (configured in FS) pins to AF12
* @arg GPIO_AF_SDIO: Connect SDIO pins to AF12
* @arg GPIO_AF_DCMI: Connect DCMI pins to AF13
* @arg GPIO_AF_EVENTOUT: Connect EVENTOUT pins to AF15
4.使用GPIO_ReadInputData(GPIO_TypeDef* GPIOx)和GPIO_ReadInputDataBit(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin)读输入信号
5.使用GPIO_SetBits()/GPIO_ResetBits()设置输出引脚
6.上电或复位后，引脚备用功能都没启用（JTAG引脚除外），为悬浮输入状态
7.LSE引脚OSC32_IN 和OSC32_OUT（PC14 and PC15）的优先级高于GPIO
8.HSE引脚OSC_IN/OSC_OUT （PH0 / PH1）的优先级高于GPIO

Answer 3

指定可复用引脚的为指定功能。在STM32中常常同一组引脚有不同的功能（比如uart,I2C,SPI等），但不是同一时刻它们同时有这些不同功能，使用GPIO_PinAFConfig函数可以为某一指定的功能。（比如为SPI1）本回答被网友采纳