STM32从零开始（四）详解GPIO库函数

目录

常用的就是这几个：
1 初始化端口
5 读取端口的输出数据
7，8 给端口写1，0
14 选择中断线

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位带操作可以参考这篇文章
https://blog.csdn.net/oshan2012/article/details/95938302

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1.GPIO设置函数（端口号，对端口的设置）

/**
  * @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
  */
假设使用a口
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));  //断言机制，就是判断给进来的参数是不是符合要求的参数。防止使用者乱给参数
  
/*---------------------------- GPIO Mode Configuration -----------------------*/
  currentmode = ((uint32_t)GPIO_InitStruct->GPIO_Mode) & ((uint32_t)0x0F);
 
  //这个大有玄机
  /*
typedef enum
{ GPIO_Mode_AIN = 0x0,
  GPIO_Mode_IN_FLOATING = 0x04,//0100
  GPIO_Mode_IPD = 0x28, //1000
  GPIO_Mode_IPU = 0x48,
  GPIO_Mode_Out_OD = 0x14,//0100
  GPIO_Mode_Out_PP = 0x10,
  GPIO_Mode_AF_OD = 0x1C,//1100
  GPIO_Mode_AF_PP = 0x18
}GPIOMode_TypeDef;
这便是GPIOmode里边的东西。我们可以发现，他所有的参数最低两位都是0.这里记住，后边要考
而且高4位的最低位，也就是左边的数字是0x1*开头的都是输出模式，比如0x14。开头不是0x1的就是输入模式。4输入4输出。
所以上边那句0x0f与他的低位，就是把判断输入还是输出剔除了。就留下低四位，用来判断她是哪种类型的。
*/


  if ((((uint32_t)GPIO_InitStruct->GPIO_Mode) & ((uint32_t)0x10)) != 0x00)//这句话判断的是她是否是输出模式。因为输出模式是0x1*。
  { 
    /* Check the parameters */
    assert_param(IS_GPIO_SPEED(GPIO_InitStruct->GPIO_Speed));
    /* Output mode */
    currentmode |= (uint32_t)GPIO_InitStruct->GPIO_Speed;
/*

typedef enum
{ 
  GPIO_Speed_10MHz = 1,
  GPIO_Speed_2MHz, 
  GPIO_Speed_50MHz
}GPIOSpeed_TypeDef;
分别是1，2，3.枚举类型。也就是0001,0010,0011
上面说到，GPIOmode的最低两位都是0，所以
currentmode 或上这三个 ，不会影响

*/


  }
/*---------------------------- GPIO CRL Configuration ------------------------*/
  /* Configure the eight low port pins */
  if (((uint32_t)GPIO_InitStruct->GPIO_Pin & ((uint32_t)0x00FF)) != 0x00)
  //低8位
  {
    tmpreg = GPIOx->CRL;
 /*这些就是每个引脚的定义。GPIOA叫端口port，pin0叫引脚。每个端口16个引脚
#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 */
*/


    for (pinpos = 0x00; pinpos < 0x08; pinpos++)//8个引脚
    {
      pos = ((uint32_t)0x01) << pinpos;//选择对应的引脚 第2次0x01 ，0001 左移1位，0010
      /* Get the port pins position */
      //pinpos = 0x01 ; pos  = 0x02; currentpin  = 0010
      currentpin = (GPIO_InitStruct->GPIO_Pin) & pos;//再次确认
      if (currentpin == pos)
      {
        pos = pinpos << 2;//0100,4
        /* Clear the corresponding low control register bits */
        pinmask = ((uint32_t)0x0F) << pos;//11110000
        tmpreg &= ~pinmask; //GPIOx->CRL;//00001111
        /* Write the mode configuration in the corresponding bits */
        tmpreg |= (currentmode << pos);//0010<<4=0010 0000
        /* 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;
  }
}

都注释在里边了。

---

2.GPIO初始化结构体函数（）

把对端口的设置结构体初始化。比如GPIO_Pin_All，就是全置一，让人一看就知道，这是初始化完的。

/**
  * @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;
}

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3.读取某个端口的某个引脚的输入值（端口，引脚）

/**
  * @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)
  //为什么这样判断呢？因为gpio_pin的定义是0x0001，0x0002,0x0004,0x0008这种样子定义的
  //所以idr与对应的引脚后，要判断1在哪一位很复杂，不如直接判断是不是不等于0，只要不等于0，那就说明
  //这一位肯定是1.非常巧妙
  
  {
    bitstatus = (uint8_t)Bit_SET;
  }
  else
  {
    bitstatus = (uint8_t)Bit_RESET;
  }
  return bitstatus;
}

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4.读取某个端口的所有引脚输入数据

对应的IDR寄存器是只读的。

/**
  * @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);
}

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5.读取某个端口的某个引脚的输出数据

ODR寄存器是可读可写的。所以读取方法和上边一样

/**
  * @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;
}

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6.读取某个端口的所有引脚输出数据

和上边输入是一样的

/**
  * @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);
}

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7.给某个端口的某个引脚写1

/**
  * @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;
}

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8.给某个端口的某个引脚写0

BSRR可1可0
BRR只能置0

/**
  * @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;
}

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9.既可以给某个引脚写1，又可以写0

评语：脱裤子放屁——多此一举

/**
  * @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;
  }
}

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10.直接给整个端口写

/**
  * @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;
}

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11.锁定端口的配置

每个位对应CRH或CRL中的4个位。因为CRL、H中每4个位配置一个引脚

/**
  * @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;
}

很简单要锁哪个就用哪个pin
但是16位置一，或上pin口，得到一个变量
不停操作这个变量和pin口来达到图中锁定配置需要的时序

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12.选择用作事件输出的GPIO引脚

/**
  * @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;
}

就是这个寄存器

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13.启用或禁用事件输出

/**
  * @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;
}

位带操作，控制这1位
置一后事件就会指导设置好的pin口上

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14.选择用作外部中断线的GPIO引脚

/**
  * @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)));
}