AMiRo-OS

/**

  ******************************************************************************

  * @file    stm32f4xx_rng.c

  * @author  MCD Application Team

  * @version V1.1.0

  * @date    11-January-2013

  * @brief This file provides firmware functions to manage the following 

  *          functionalities of the Random Number Generator (RNG) peripheral:           

  *           + Initialization and Configuration 

  *           + Get 32 bit Random number      

  *           + Interrupts and flags management       

  *         

@verbatim

 ===================================================================      

                 ##### How to use this driver #####

 ===================================================================          

 [..]

   (#) Enable The RNG controller clock using 

       RCC_AHB2PeriphClockCmd(RCC_AHB2Periph_RNG, ENABLE) function.

   (#) Activate the RNG peripheral using RNG_Cmd() function.

   (#) Wait until the 32 bit Random number Generator contains a valid  random data

      (using polling/interrupt mode). For more details, refer to "Interrupts and 

      flags management functions" module description.

   (#) Get the 32 bit Random number using RNG_GetRandomNumber() function

   (#) To get another 32 bit Random number, go to step 3.       

@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_rng.h"

#include "stm32f4xx_rcc.h"

/** @addtogroup STM32F4xx_StdPeriph_Driver

  * @{

  */

/** @defgroup RNG 

  * @brief RNG driver modules

  * @{

  */ 

/* Private typedef -----------------------------------------------------------*/

/* Private define ------------------------------------------------------------*/

/* Private macro -------------------------------------------------------------*/

/* Private variables ---------------------------------------------------------*/

/* Private function prototypes -----------------------------------------------*/

/* Private functions ---------------------------------------------------------*/

/** @defgroup RNG_Private_Functions

  * @{

  */ 

/** @defgroup RNG_Group1 Initialization and Configuration functions

 *  @brief    Initialization and Configuration functions 

 *

@verbatim    

 ===============================================================================

             ##### Initialization and Configuration functions #####

 ===============================================================================  

 [..] This section provides functions allowing to 

   (+) Initialize the RNG peripheral

   (+) Enable or disable the RNG peripheral

@endverbatim

  * @{

  */

/**

  * @brief  De-initializes the RNG peripheral registers to their default reset values.

  * @param  None

  * @retval None

  */

void RNG_DeInit(void)

{

  /* Enable RNG reset state */

  RCC_AHB2PeriphResetCmd(RCC_AHB2Periph_RNG, ENABLE);

  /* Release RNG from reset state */

  RCC_AHB2PeriphResetCmd(RCC_AHB2Periph_RNG, DISABLE);

}

/**

  * @brief  Enables or disables the RNG peripheral.

  * @param  NewState: new state of the RNG peripheral.

  *          This parameter can be: ENABLE or DISABLE.

  * @retval None

  */

void RNG_Cmd(FunctionalState NewState)

{

  /* Check the parameters */

  assert_param(IS_FUNCTIONAL_STATE(NewState));

  if (NewState != DISABLE)

  {

    /* Enable the RNG */

    RNG->CR |= RNG_CR_RNGEN;

  }

  else

  {

    /* Disable the RNG */

    RNG->CR &= ~RNG_CR_RNGEN;

  }

}

/**

  * @}

  */

/** @defgroup RNG_Group2 Get 32 bit Random number function

 *  @brief    Get 32 bit Random number function 

 *

@verbatim    

 ===============================================================================

                 ##### Get 32 bit Random number function #####

 ===============================================================================  

 [..] This section provides a function allowing to get the 32 bit Random number  

   (@)  Before to call this function you have to wait till DRDY flag is set,

        using RNG_GetFlagStatus(RNG_FLAG_DRDY) function. 

@endverbatim

  * @{

  */

/**

  * @brief  Returns a 32-bit random number.

  *   

  * @note   Before to call this function you have to wait till DRDY (data ready)

  *         flag is set, using RNG_GetFlagStatus(RNG_FLAG_DRDY) function.

  * @note   Each time the the Random number data is read (using RNG_GetRandomNumber()

  *         function), the RNG_FLAG_DRDY flag is automatically cleared.

  * @note   In the case of a seed error, the generation of random numbers is 

  *         interrupted for as long as the SECS bit is '1'. If a number is 

  *         available in the RNG_DR register, it must not be used because it may 

  *         not have enough entropy. In this case, it is recommended to clear the 

  *         SEIS bit(using RNG_ClearFlag(RNG_FLAG_SECS) function), then disable 

  *         and enable the RNG peripheral (using RNG_Cmd() function) to 

  *         reinitialize and restart the RNG.

  * @note   In the case of a clock error, the RNG is no more able to generate 

  *         random numbers because the PLL48CLK clock is not correct. User have 

  *         to check that the clock controller is correctly configured to provide

  *         the RNG clock and clear the CEIS bit (using RNG_ClearFlag(RNG_FLAG_CECS) 

  *         function) . The clock error has no impact on the previously generated 

  *         random numbers, and the RNG_DR register contents can be used.

  *         

  * @param  None

  * @retval 32-bit random number.

  */

uint32_t RNG_GetRandomNumber(void)

{

  /* Return the 32 bit random number from the DR register */

  return RNG->DR;

}

/**

  * @}

  */

/** @defgroup RNG_Group3 Interrupts and flags management functions

 *  @brief   Interrupts and flags management functions

 *

@verbatim   

 ===============================================================================

             ##### Interrupts and flags management functions #####

 ===============================================================================  

 [..] This section provides functions allowing to configure the RNG Interrupts and 

      to get the status and clear flags and Interrupts pending bits.

 [..] The RNG provides 3 Interrupts sources and 3 Flags:

 *** Flags : ***

 ===============

 [..] 

    (#) RNG_FLAG_DRDY :  In the case of the RNG_DR register contains valid 

        random data. it is cleared by reading the valid data(using 

        RNG_GetRandomNumber() function).

    (#) RNG_FLAG_CECS : In the case of a seed error detection. 

    (#) RNG_FLAG_SECS : In the case of a clock error detection.

 *** Interrupts ***

 ==================

 [..] If enabled, an RNG interrupt is pending :

   (#) In the case of the RNG_DR register contains valid random data. 

       This interrupt source is cleared once the RNG_DR register has been read 

       (using RNG_GetRandomNumber() function) until a new valid value is 

       computed; or 

   (#) In the case of a seed error : One of the following faulty sequences has 

       been detected:

       (++) More than 64 consecutive bits at the same value (0 or 1)

       (++) More than 32 consecutive alternance of 0 and 1 (0101010101...01)

       This interrupt source is cleared using RNG_ClearITPendingBit(RNG_IT_SEI)

       function; or

   (#) In the case of a clock error : the PLL48CLK (RNG peripheral clock source) 

       was not correctly detected (fPLL48CLK< fHCLK/16). This interrupt source is

       cleared using RNG_ClearITPendingBit(RNG_IT_CEI) function.

       -@- note In this case, User have to check that the clock controller is 

           correctly configured to provide the RNG clock. 

 *** Managing the RNG controller events : ***

 ============================================

 [..] The user should identify which mode will be used in his application to manage 

      the RNG controller events: Polling mode or Interrupt mode.

   (#) In the Polling Mode it is advised to use the following functions:

       (++) RNG_GetFlagStatus() : to check if flags events occur. 

       (++) RNG_ClearFlag()     : to clear the flags events.

       -@@- RNG_FLAG_DRDY can not be cleared by RNG_ClearFlag(). it is cleared only 

            by reading the Random number data.      

   (#)  In the Interrupt Mode it is advised to use the following functions:

        (++) RNG_ITConfig()       : to enable or disable the interrupt source.

        (++) RNG_GetITStatus()    : to check if Interrupt occurs.

        (++) RNG_ClearITPendingBit() : to clear the Interrupt pending Bit 

             (corresponding Flag). 

@endverbatim

  * @{

  */ 

/**

  * @brief  Enables or disables the RNG interrupt.

  * @note   The RNG provides 3 interrupt sources,

  *           - Computed data is ready event (DRDY), and           

  *           - Seed error Interrupt (SEI) and 

  *           - Clock error Interrupt (CEI), 

  *         all these interrupts sources are enabled by setting the IE bit in 

  *         CR register. However, each interrupt have its specific status bit

  *         (see RNG_GetITStatus() function) and clear bit except the DRDY event

  *         (see RNG_ClearITPendingBit() function).

  * @param  NewState: new state of the RNG interrupt.

  *          This parameter can be: ENABLE or DISABLE.

  * @retval None

  */

void RNG_ITConfig(FunctionalState NewState)

{

  /* Check the parameters */

  assert_param(IS_FUNCTIONAL_STATE(NewState));

  if (NewState != DISABLE)

  {

    /* Enable the RNG interrupt */

    RNG->CR |= RNG_CR_IE;

  }

  else

  {

    /* Disable the RNG interrupt */

    RNG->CR &= ~RNG_CR_IE;

  }

}

/**

  * @brief  Checks whether the specified RNG flag is set or not.

  * @param  RNG_FLAG: specifies the RNG flag to check.

  *          This parameter can be one of the following values:

  *            @arg RNG_FLAG_DRDY: Data Ready flag.

  *            @arg RNG_FLAG_CECS: Clock Error Current flag.

  *            @arg RNG_FLAG_SECS: Seed Error Current flag.

  * @retval The new state of RNG_FLAG (SET or RESET).

  */

FlagStatus RNG_GetFlagStatus(uint8_t RNG_FLAG)

{

  FlagStatus bitstatus = RESET;

  /* Check the parameters */

  assert_param(IS_RNG_GET_FLAG(RNG_FLAG));

  /* Check the status of the specified RNG flag */

  if ((RNG->SR & RNG_FLAG) != (uint8_t)RESET)

  {

    /* RNG_FLAG is set */

    bitstatus = SET;

  }

  else

  {

    /* RNG_FLAG is reset */

    bitstatus = RESET;

  }

  /* Return the RNG_FLAG status */

  return  bitstatus;

}

/**

  * @brief  Clears the RNG flags.

  * @param  RNG_FLAG: specifies the flag to clear. 

  *          This parameter can be any combination of the following values:

  *            @arg RNG_FLAG_CECS: Clock Error Current flag.

  *            @arg RNG_FLAG_SECS: Seed Error Current flag.

  * @note   RNG_FLAG_DRDY can not be cleared by RNG_ClearFlag() function. 

  *         This flag is cleared only by reading the Random number data (using 

  *         RNG_GetRandomNumber() function).                           

  * @retval None

  */

void RNG_ClearFlag(uint8_t RNG_FLAG)

{

  /* Check the parameters */

  assert_param(IS_RNG_CLEAR_FLAG(RNG_FLAG));

  /* Clear the selected RNG flags */

  RNG->SR = ~(uint32_t)(((uint32_t)RNG_FLAG) << 4);

}

/**

  * @brief  Checks whether the specified RNG interrupt has occurred or not.

  * @param  RNG_IT: specifies the RNG interrupt source to check.

  *          This parameter can be one of the following values:

  *            @arg RNG_IT_CEI: Clock Error Interrupt.

  *            @arg RNG_IT_SEI: Seed Error Interrupt.                   

  * @retval The new state of RNG_IT (SET or RESET).

  */

ITStatus RNG_GetITStatus(uint8_t RNG_IT)

{

  ITStatus bitstatus = RESET;

  /* Check the parameters */

  assert_param(IS_RNG_GET_IT(RNG_IT));

  /* Check the status of the specified RNG interrupt */

  if ((RNG->SR & RNG_IT) != (uint8_t)RESET)

  {

    /* RNG_IT is set */

    bitstatus = SET;

  }

  else

  {

    /* RNG_IT is reset */

    bitstatus = RESET;

  }

  /* Return the RNG_IT status */

  return bitstatus;

}

/**

  * @brief  Clears the RNG interrupt pending bit(s).

  * @param  RNG_IT: specifies the RNG interrupt pending bit(s) to clear.

  *          This parameter can be any combination of the following values:

  *            @arg RNG_IT_CEI: Clock Error Interrupt.

  *            @arg RNG_IT_SEI: Seed Error Interrupt.

  * @retval None

  */

void RNG_ClearITPendingBit(uint8_t RNG_IT)

{

  /* Check the parameters */

  assert_param(IS_RNG_IT(RNG_IT));

  /* Clear the selected RNG interrupt pending bit */

  RNG->SR = (uint8_t)~RNG_IT;

}

/**

  * @}

  */ 

/**

  * @}

  */ 

/**

  * @}

  */ 

/**

  * @}

  */ 

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