circuitpython/stm/lib/stm32f4xx_gpio.c

/**
  ******************************************************************************
  * @file    stm32f4xx_gpio.c
  * @author  MCD Application Team
  * @version V1.3.0
  * @date    08-November-2013
  * @brief   This file provides firmware functions to manage the following 
  *          functionalities of the GPIO peripheral:           
  *           + Initialization and Configuration
  *           + GPIO Read and Write
  *           + GPIO Alternate functions configuration
  * 
@verbatim  
 ===============================================================================
                      ##### How to use this driver #####
 ===============================================================================       
 [..]             
   (#) Enable the GPIO AHB clock using the following function
       RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOx, ENABLE);
               
   (#) Configure the GPIO pin(s) using GPIO_Init()
       Four possible configuration are available for each pin:
       (++) Input: Floating, Pull-up, Pull-down.
       (++) Output: Push-Pull (Pull-up, Pull-down or no Pull)
            Open Drain (Pull-up, Pull-down or no Pull). In output mode, the speed 
            is configurable: 2 MHz, 25 MHz, 50 MHz or 100 MHz.
       (++) Alternate Function: Push-Pull (Pull-up, Pull-down or no Pull) Open 
            Drain (Pull-up, Pull-down or no Pull).
       (++) Analog: required mode when a pin is to be used as ADC channel or DAC 
            output.
   
   (#) Peripherals alternate function:
       (++) For ADC and DAC, configure the desired pin in analog mode using 
            GPIO_InitStruct->GPIO_Mode = GPIO_Mode_AN;
            (+++) For other peripherals (TIM, USART...):
            (+++) Connect the pin to the desired peripherals' Alternate 
                     Function (AF) using GPIO_PinAFConfig() function
            (+++) Configure the desired pin in alternate function mode using
                     GPIO_InitStruct->GPIO_Mode = GPIO_Mode_AF
            (+++) Select the type, pull-up/pull-down and output speed via 
                     GPIO_PuPd, GPIO_OType and GPIO_Speed members
            (+++) Call GPIO_Init() function
          
   (#) To get the level of a pin configured in input mode use GPIO_ReadInputDataBit()
            
   (#) To set/reset the level of a pin configured in output mode use 
       GPIO_SetBits()/GPIO_ResetBits()
                 
   (#) During and just after reset, the alternate functions are not 
       active and the GPIO pins are configured in input floating mode (except JTAG
       pins).
  
   (#) The LSE oscillator pins OSC32_IN and OSC32_OUT can be used as general purpose 
       (PC14 and PC15, respectively) when the LSE oscillator is off. The LSE has 
       priority over the GPIO function.
  
   (#) The HSE oscillator pins OSC_IN/OSC_OUT can be used as 
       general purpose PH0 and PH1, respectively, when the HSE oscillator is off. 
       The HSE has priority over the GPIO function.
               
@endverbatim        
  *
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; COPYRIGHT 2013 STMicroelectronics</center></h2>
  *
  * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
  * You may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *        http://www.st.com/software_license_agreement_liberty_v2
  *
  * Unless required by applicable law or agreed to in writing, software 
  * distributed under the License is distributed on an "AS IS" BASIS, 
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
  ******************************************************************************
  */

/* Includes ------------------------------------------------------------------*/
#include "stm32f4xx_gpio.h"
#include "stm32f4xx_rcc.h"

/** @addtogroup STM32F4xx_StdPeriph_Driver
  * @{
  */

/** @defgroup GPIO 
  * @brief GPIO driver modules
  * @{
  */ 

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/

/** @defgroup GPIO_Private_Functions
  * @{
  */ 

/** @defgroup GPIO_Group1 Initialization and Configuration
 *  @brief   Initialization and Configuration
 *
@verbatim   
 ===============================================================================
                 ##### Initialization and Configuration #####
 ===============================================================================  

@endverbatim
  * @{
  */

/**
  * @brief  De-initializes the GPIOx peripheral registers to their default reset values.
  * @note   By default, The GPIO pins are configured in input floating mode (except JTAG pins).
  * @param  GPIOx: where x can be (A..K) to select the GPIO peripheral for STM32F405xx/407xx and STM32F415xx/417xx devices
  *                      x can be (A..I) to select the GPIO peripheral for STM32F42xxx/43xxx devices.
  *                      x can be (A, B, C, D and H) to select the GPIO peripheral for STM32F401xx devices.  
  * @retval None
  */
void GPIO_DeInit(GPIO_TypeDef* GPIOx)
{
  /* Check the parameters */
  assert_param(IS_GPIO_ALL_PERIPH(GPIOx));

  if (GPIOx == GPIOA)
  {
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOA, ENABLE);
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOA, DISABLE);
  }
  else if (GPIOx == GPIOB)
  {
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOB, ENABLE);
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOB, DISABLE);
  }
  else if (GPIOx == GPIOC)
  {
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOC, ENABLE);
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOC, DISABLE);
  }
  else if (GPIOx == GPIOD)
  {
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOD, ENABLE);
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOD, DISABLE);
  }
  else if (GPIOx == GPIOE)
  {
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOE, ENABLE);
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOE, DISABLE);
  }
  else if (GPIOx == GPIOF)
  {
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOF, ENABLE);
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOF, DISABLE);
  }
  else if (GPIOx == GPIOG)
  {
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOG, ENABLE);
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOG, DISABLE);
  }
  else if (GPIOx == GPIOH)
  {
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOH, ENABLE);
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOH, DISABLE);
  }

  else if (GPIOx == GPIOI)
  {
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOI, ENABLE);
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOI, DISABLE);
  }
  else if (GPIOx == GPIOJ)
  {
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOJ, ENABLE);
    RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOJ, DISABLE);
  }
  else
  {
    if (GPIOx == GPIOK)
    {
      RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOK, ENABLE);
      RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_GPIOK, DISABLE);
    }
  }
}

/**
  * @brief  Initializes the GPIOx peripheral according to the specified parameters in the GPIO_InitStruct.
  * @param  GPIOx: where x can be (A..K) to select the GPIO peripheral for STM32F405xx/407xx and STM32F415xx/417xx devices
  *                      x can be (A..I) to select the GPIO peripheral for STM32F42xxx/43xxx devices.
  *                      x can be (A, B, C, D and H) to select the GPIO peripheral for STM32F401xx devices.   
  * @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 pinpos = 0x00, pos = 0x00 , currentpin = 0x00;

  /* Check the parameters */
  assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
  assert_param(IS_GPIO_PIN(GPIO_InitStruct->GPIO_Pin));
  assert_param(IS_GPIO_MODE(GPIO_InitStruct->GPIO_Mode));
  assert_param(IS_GPIO_PUPD(GPIO_InitStruct->GPIO_PuPd));

  /* ------------------------- Configure the port pins ---------------- */
  /*-- GPIO Mode Configuration --*/
  for (pinpos = 0x00; pinpos < 0x10; pinpos++)
  {
    pos = ((uint32_t)0x01) << pinpos;
    /* Get the port pins position */
    currentpin = (GPIO_InitStruct->GPIO_Pin) & pos;

    if (currentpin == pos)
    {
      GPIOx->MODER  &= ~(GPIO_MODER_MODER0 << (pinpos * 2));
      GPIOx->MODER |= (((uint32_t)GPIO_InitStruct->GPIO_Mode) << (pinpos * 2));

      if ((GPIO_InitStruct->GPIO_Mode == GPIO_Mode_OUT) || (GPIO_InitStruct->GPIO_Mode == GPIO_Mode_AF))
      {
        /* Check Speed mode parameters */
        assert_param(IS_GPIO_SPEED(GPIO_InitStruct->GPIO_Speed));

        /* Speed mode configuration */
        GPIOx->OSPEEDR &= ~(GPIO_OSPEEDER_OSPEEDR0 << (pinpos * 2));
        GPIOx->OSPEEDR |= ((uint32_t)(GPIO_InitStruct->GPIO_Speed) << (pinpos * 2));

        /* Check Output mode parameters */
        assert_param(IS_GPIO_OTYPE(GPIO_InitStruct->GPIO_OType));

        /* Output mode configuration*/
        GPIOx->OTYPER  &= ~((GPIO_OTYPER_OT_0) << ((uint16_t)pinpos)) ;
        GPIOx->OTYPER |= (uint16_t)(((uint16_t)GPIO_InitStruct->GPIO_OType) << ((uint16_t)pinpos));
      }

      /* Pull-up Pull down resistor configuration*/
      GPIOx->PUPDR &= ~(GPIO_PUPDR_PUPDR0 << ((uint16_t)pinpos * 2));
      GPIOx->PUPDR |= (((uint32_t)GPIO_InitStruct->GPIO_PuPd) << (pinpos * 2));
    }
  }
}

/**
  * @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_Mode = GPIO_Mode_IN;
  GPIO_InitStruct->GPIO_Speed = GPIO_Speed_2MHz;
  GPIO_InitStruct->GPIO_OType = GPIO_OType_PP;
  GPIO_InitStruct->GPIO_PuPd = GPIO_PuPd_NOPULL;
}

/**
  * @brief  Locks GPIO Pins configuration registers.
  * @note   The locked registers are GPIOx_MODER, GPIOx_OTYPER, GPIOx_OSPEEDR,
  *         GPIOx_PUPDR, GPIOx_AFRL and GPIOx_AFRH.
  * @note   The configuration of the locked GPIO pins can no longer be modified
  *         until the next reset.
  * @param  GPIOx: where x can be (A..K) to select the GPIO peripheral for STM32F405xx/407xx and STM32F415xx/417xx devices
  *                      x can be (A..I) to select the GPIO peripheral for STM32F42xxx/43xxx devices.
  *                      x can be (A, B, C, D and H) to select the GPIO peripheral for STM32F401xx devices. 
  * @param  GPIO_Pin: specifies the port bit to be locked.
  *          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)
{
  __IO 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;
}

/**
  * @}
  */

/** @defgroup GPIO_Group2 GPIO Read and Write
 *  @brief   GPIO Read and Write
 *
@verbatim   
 ===============================================================================
                         ##### GPIO Read and Write #####
 ===============================================================================  

@endverbatim
  * @{
  */

/**
  * @brief  Reads the specified input port pin.
  * @param  GPIOx: where x can be (A..K) to select the GPIO peripheral for STM32F405xx/407xx and STM32F415xx/417xx devices
  *                      x can be (A..I) to select the GPIO peripheral for STM32F42xxx/43xxx devices.
  *                      x can be (A, B, C, D and H) to select the GPIO peripheral for STM32F401xx devices. 
  * @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)
  {
    bitstatus = (uint8_t)Bit_SET;
  }
  else
  {
    bitstatus = (uint8_t)Bit_RESET;
  }
  return bitstatus;
}

/**
  * @brief  Reads the specified GPIO input data port.
  * @param  GPIOx: where x can be (A..K) to select the GPIO peripheral for STM32F405xx/407xx and STM32F415xx/417xx devices
  *                      x can be (A..I) to select the GPIO peripheral for STM32F42xxx/43xxx devices.
  *                      x can be (A, B, C, D and H) to select the GPIO peripheral for STM32F401xx devices. 
  * @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);
}

/**
  * @brief  Reads the specified output data port bit.
  * @param  GPIOx: where x can be (A..K) to select the GPIO peripheral for STM32F405xx/407xx and STM32F415xx/417xx devices
  *                      x can be (A..I) to select the GPIO peripheral for STM32F42xxx/43xxx devices.
  *                      x can be (A, B, C, D and H) to select the GPIO peripheral for STM32F401xx devices. 
  * @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;
}

/**
  * @brief  Reads the specified GPIO output data port.
  * @param  GPIOx: where x can be (A..K) to select the GPIO peripheral for STM32F405xx/407xx and STM32F415xx/417xx devices
  *                      x can be (A..I) to select the GPIO peripheral for STM32F42xxx/43xxx devices.
  *                      x can be (A, B, C, D and H) to select the GPIO peripheral for STM32F401xx devices. 
  * @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);
}

/**
  * @brief  Sets the selected data port bits.
  * @note   This functions uses GPIOx_BSRR register to allow atomic read/modify 
  *         accesses. In this way, there is no risk of an IRQ occurring between
  *         the read and the modify access.
  * @param  GPIOx: where x can be (A..K) to select the GPIO peripheral for STM32F405xx/407xx and STM32F415xx/417xx devices
  *                      x can be (A..I) to select the GPIO peripheral for STM32F42xxx/43xxx devices.
  *                      x can be (A, B, C, D and H) to select the GPIO peripheral for STM32F401xx devices. 
  * @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->BSRRL = GPIO_Pin;
}

/**
  * @brief  Clears the selected data port bits.
  * @note   This functions uses GPIOx_BSRR register to allow atomic read/modify 
  *         accesses. In this way, there is no risk of an IRQ occurring between
  *         the read and the modify access.
  * @param  GPIOx: where x can be (A..K) to select the GPIO peripheral for STM32F405xx/407xx and STM32F415xx/417xx devices
  *                      x can be (A..I) to select the GPIO peripheral for STM32F42xxx/43xxx devices.
  *                      x can be (A, B, C, D and H) to select the GPIO peripheral for STM32F401xx devices. 
  * @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->BSRRH = GPIO_Pin;
}

/**
  * @brief  Sets or clears the selected data port bit.
  * @param  GPIOx: where x can be (A..K) to select the GPIO peripheral for STM32F405xx/407xx and STM32F415xx/417xx devices
  *                      x can be (A..I) to select the GPIO peripheral for STM32F42xxx/43xxx devices.
  *                      x can be (A, B, C, D and H) to select the GPIO peripheral for STM32F401xx devices. 
  * @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->BSRRL = GPIO_Pin;
  }
  else
  {
    GPIOx->BSRRH = GPIO_Pin ;
  }
}

/**
  * @brief  Writes data to the specified GPIO data port.
  * @param  GPIOx: where x can be (A..K) to select the GPIO peripheral for STM32F405xx/407xx and STM32F415xx/417xx devices
  *                      x can be (A..I) to select the GPIO peripheral for STM32F42xxx/43xxx devices.
  *                      x can be (A, B, C, D and H) to select the GPIO peripheral for STM32F401xx devices. 
  * @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;
}

/**
  * @brief  Toggles the specified GPIO pins..
  * @param  GPIOx: where x can be (A..K) to select the GPIO peripheral for STM32F405xx/407xx and STM32F415xx/417xx devices
  *                      x can be (A..I) to select the GPIO peripheral for STM32F42xxx/43xxx devices.
  *                      x can be (A, B, C, D and H) to select the GPIO peripheral for STM32F401xx devices. 
  * @param  GPIO_Pin: Specifies the pins to be toggled.
  * @retval None
  */
void GPIO_ToggleBits(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin)
{
  /* Check the parameters */
  assert_param(IS_GPIO_ALL_PERIPH(GPIOx));

  GPIOx->ODR ^= GPIO_Pin;
}

/**
  * @}
  */

/** @defgroup GPIO_Group3 GPIO Alternate functions configuration function
 *  @brief   GPIO Alternate functions configuration function
 *
@verbatim   
 ===============================================================================
           ##### GPIO Alternate functions configuration function #####
 ===============================================================================  

@endverbatim
  * @{
  */

/**
  * @brief  Changes the mapping of the specified pin.
  * @param  GPIOx: where x can be (A..K) to select the GPIO peripheral for STM32F405xx/407xx and STM32F415xx/417xx devices
  *                      x can be (A..I) to select the GPIO peripheral for STM32F42xxx/43xxx devices.
  *                      x can be (A, B, C, D and H) to select the GPIO peripheral for STM32F401xx devices. 
  * @param  GPIO_PinSource: specifies the pin for the Alternate function.
  *         This parameter can be GPIO_PinSourcex where x can be (0..15).
  * @param  GPIO_AFSelection: selects the pin to used as Alternate function.
  *          This parameter 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_SPI4: Connect SPI4 pins to AF5 
  *            @arg GPIO_AF_SPI5: Connect SPI5 pins to AF5 
  *            @arg GPIO_AF_SPI6: Connect SPI6 pins to AF5
  *            @arg GPIO_AF_SAI1: Connect SAI1 pins to AF6 for STM32F42xxx/43xxx devices.       
  *            @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_UART7: Connect UART7 pins to AF8
  *            @arg GPIO_AF_UART8: Connect UART8 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_FMC: Connect FMC pins to AF12 for STM32F42xxx/43xxx devices.   
  *            @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_LTDC: Connect LTDC pins to AF14 for STM32F429xx/439xx devices. 
  *            @arg GPIO_AF_EVENTOUT: Connect EVENTOUT pins to AF15
  * @retval None
  */
void GPIO_PinAFConfig(GPIO_TypeDef* GPIOx, uint16_t GPIO_PinSource, uint8_t GPIO_AF)
{
  uint32_t temp = 0x00;
  uint32_t temp_2 = 0x00;
  
  /* Check the parameters */
  assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
  assert_param(IS_GPIO_PIN_SOURCE(GPIO_PinSource));
  assert_param(IS_GPIO_AF(GPIO_AF));
  
  temp = ((uint32_t)(GPIO_AF) << ((uint32_t)((uint32_t)GPIO_PinSource & (uint32_t)0x07) * 4)) ;
  GPIOx->AFR[GPIO_PinSource >> 0x03] &= ~((uint32_t)0xF << ((uint32_t)((uint32_t)GPIO_PinSource & (uint32_t)0x07) * 4)) ;
  temp_2 = GPIOx->AFR[GPIO_PinSource >> 0x03] | temp;
  GPIOx->AFR[GPIO_PinSource >> 0x03] = temp_2;
}

/**
  * @}
  */ 

/**
  * @}
  */

/**
  * @}
  */ 

/**
  * @}
  */ 

/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/