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/**
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******************************************************************************
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* @file stm32f4xx_rng.c
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* @author MCD Application Team
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* @version V1.0.0RC1
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* @date 25-August-2011
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* @brief This file provides firmware functions to manage the following
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* functionalities of the Random Number Generator (RNG) peripheral:
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* - Initialization and Configuration
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* - Get 32 bit Random number
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* - Interrupts and flags management
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*
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* @verbatim
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*
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* ===================================================================
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* How to use this driver
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* ===================================================================
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* 1. Enable The RNG controller clock using
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* RCC_AHB2PeriphClockCmd(RCC_AHB2Periph_RNG, ENABLE) function.
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*
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* 2. Activate the RNG peripheral using RNG_Cmd() function.
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*
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* 3. Wait until the 32 bit Random number Generator contains a valid
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* random data (using polling/interrupt mode). For more details,
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* refer to "Interrupts and flags management functions" module
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* description.
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*
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* 4. Get the 32 bit Random number using RNG_GetRandomNumber() function
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*
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* 5. To get another 32 bit Random number, go to step 3.
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*
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*
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*
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* @endverbatim
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*
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******************************************************************************
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* @attention
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*
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* THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
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* WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE
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* TIME. AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY
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* DIRECT, INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING
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* FROM THE CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE
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* CODING INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
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*
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* <h2><center>© COPYRIGHT 2011 STMicroelectronics</center></h2>
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******************************************************************************
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*/
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/* Includes ------------------------------------------------------------------*/
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#include "stm32f4xx_rng.h"
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#include "stm32f4xx_rcc.h"
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/** @addtogroup STM32F4xx_StdPeriph_Driver
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* @{
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*/
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/** @defgroup RNG
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* @brief RNG driver modules
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* @{
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*/
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/* Private typedef -----------------------------------------------------------*/
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/* Private define ------------------------------------------------------------*/
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/* Private macro -------------------------------------------------------------*/
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/* Private variables ---------------------------------------------------------*/
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/* Private function prototypes -----------------------------------------------*/
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/* Private functions ---------------------------------------------------------*/
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/** @defgroup RNG_Private_Functions
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* @{
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*/
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/** @defgroup RNG_Group1 Initialization and Configuration functions
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* @brief Initialization and Configuration functions
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*
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@verbatim
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===============================================================================
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Initialization and Configuration functions
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===============================================================================
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This section provides functions allowing to
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- Initialize the RNG peripheral
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- Enable or disable the RNG peripheral
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@endverbatim
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* @{
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*/
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/**
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* @brief Deinitializes the RNG peripheral registers to their default reset values.
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* @param None
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* @retval None
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*/
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void RNG_DeInit(void)
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{
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/* Enable RNG reset state */
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RCC_AHB2PeriphResetCmd(RCC_AHB2Periph_RNG, ENABLE);
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/* Release RNG from reset state */
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RCC_AHB2PeriphResetCmd(RCC_AHB2Periph_RNG, DISABLE);
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}
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/**
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* @brief Enables or disables the RNG peripheral.
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* @param NewState: new state of the RNG peripheral.
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* This parameter can be: ENABLE or DISABLE.
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* @retval None
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*/
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void RNG_Cmd(FunctionalState NewState)
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{
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/* Check the parameters */
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assert_param(IS_FUNCTIONAL_STATE(NewState));
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if (NewState != DISABLE)
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{
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/* Enable the RNG */
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RNG->CR |= RNG_CR_RNGEN;
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}
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else
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{
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/* Disable the RNG */
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RNG->CR &= ~RNG_CR_RNGEN;
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}
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}
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/**
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* @}
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*/
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/** @defgroup RNG_Group2 Get 32 bit Random number function
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* @brief Get 32 bit Random number function
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*
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@verbatim
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===============================================================================
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Get 32 bit Random number function
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===============================================================================
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This section provides a function allowing to get the 32 bit Random number
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@note Before to call this function you have to wait till DRDY flag is set,
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using RNG_GetFlagStatus(RNG_FLAG_DRDY) function.
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@endverbatim
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* @{
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*/
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/**
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* @brief Returns a 32-bit random number.
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*
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* @note Before to call this function you have to wait till DRDY (data ready)
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* flag is set, using RNG_GetFlagStatus(RNG_FLAG_DRDY) function.
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* @note Each time the the Random number data is read (using RNG_GetRandomNumber()
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* function), the RNG_FLAG_DRDY flag is automatically cleared.
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* @note In the case of a seed error, the generation of random numbers is
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* interrupted for as long as the SECS bit is '1'. If a number is
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* available in the RNG_DR register, it must not be used because it may
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* not have enough entropy. In this case, it is recommended to clear the
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* SEIS bit(using RNG_ClearFlag(RNG_FLAG_SECS) function), then disable
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* and enable the RNG peripheral (using RNG_Cmd() function) to
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* reinitialize and restart the RNG.
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* @note In the case of a clock error, the RNG is no more able to generate
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* random numbers because the PLL48CLK clock is not correct. User have
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* to check that the clock controller is correctly configured to provide
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* the RNG clock and clear the CEIS bit (using RNG_ClearFlag(RNG_FLAG_CECS)
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* function) . The clock error has no impact on the previously generated
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* random numbers, and the RNG_DR register contents can be used.
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*
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* @param None
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* @retval 32-bit random number.
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*/
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uint32_t RNG_GetRandomNumber(void)
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{
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/* Return the 32 bit random number from the DR register */
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return RNG->DR;
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}
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/**
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* @}
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*/
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/** @defgroup RNG_Group3 Interrupts and flags management functions
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* @brief Interrupts and flags management functions
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*
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@verbatim
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===============================================================================
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Interrupts and flags management functions
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===============================================================================
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This section provides functions allowing to configure the RNG Interrupts and
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to get the status and clear flags and Interrupts pending bits.
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The RNG provides 3 Interrupts sources and 3 Flags:
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Flags :
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----------
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1. RNG_FLAG_DRDY : In the case of the RNG_DR register contains valid
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random data. it is cleared by reading the valid data
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(using RNG_GetRandomNumber() function).
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2. RNG_FLAG_CECS : In the case of a seed error detection.
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3. RNG_FLAG_SECS : In the case of a clock error detection.
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Interrupts :
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------------
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if enabled, an RNG interrupt is pending :
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1. In the case of the RNG_DR register contains valid random data.
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This interrupt source is cleared once the RNG_DR register has been read
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(using RNG_GetRandomNumber() function) until a new valid value is
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computed.
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or
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2. In the case of a seed error : One of the following faulty sequences has
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been detected:
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- More than 64 consecutive bits at the same value (0 or 1)
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- More than 32 consecutive alternance of 0 and 1 (0101010101...01)
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This interrupt source is cleared using RNG_ClearITPendingBit(RNG_IT_SEI)
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function.
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or
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3. In the case of a clock error : the PLL48CLK (RNG peripheral clock source)
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was not correctly detected (fPLL48CLK< fHCLK/16).
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This interrupt source is cleared using RNG_ClearITPendingBit(RNG_IT_CEI)
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function.
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@note In this case, User have to check that the clock controller is
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correctly configured to provide the RNG clock.
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Managing the RNG controller events :
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------------------------------------
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The user should identify which mode will be used in his application to manage
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the RNG controller events: Polling mode or Interrupt mode.
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1. In the Polling Mode it is advised to use the following functions:
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- RNG_GetFlagStatus() : to check if flags events occur.
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- RNG_ClearFlag() : to clear the flags events.
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@note RNG_FLAG_DRDY can not be cleared by RNG_ClearFlag(). it is cleared only
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by reading the Random number data.
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2. In the Interrupt Mode it is advised to use the following functions:
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- RNG_ITConfig() : to enable or disable the interrupt source.
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- RNG_GetITStatus() : to check if Interrupt occurs.
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- RNG_ClearITPendingBit() : to clear the Interrupt pending Bit
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(corresponding Flag).
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@endverbatim
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* @{
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*/
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/**
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* @brief Enables or disables the RNG interrupt.
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* @note The RNG provides 3 interrupt sources,
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* - Computed data is ready event (DRDY), and
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* - Seed error Interrupt (SEI) and
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* - Clock error Interrupt (CEI),
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* all these interrupts sources are enabled by setting the IE bit in
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* CR register. However, each interrupt have its specific status bit
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* (see RNG_GetITStatus() function) and clear bit except the DRDY event
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* (see RNG_ClearITPendingBit() function).
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* @param NewState: new state of the RNG interrupt.
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* This parameter can be: ENABLE or DISABLE.
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* @retval None
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*/
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void RNG_ITConfig(FunctionalState NewState)
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{
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/* Check the parameters */
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assert_param(IS_FUNCTIONAL_STATE(NewState));
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if (NewState != DISABLE)
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{
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/* Enable the RNG interrupt */
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RNG->CR |= RNG_CR_IE;
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}
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else
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{
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/* Disable the RNG interrupt */
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RNG->CR &= ~RNG_CR_IE;
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}
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}
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/**
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* @brief Checks whether the specified RNG flag is set or not.
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* @param RNG_FLAG: specifies the RNG flag to check.
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* This parameter can be one of the following values:
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* @arg RNG_FLAG_DRDY: Data Ready flag.
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* @arg RNG_FLAG_CECS: Clock Error Current flag.
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* @arg RNG_FLAG_SECS: Seed Error Current flag.
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* @retval The new state of RNG_FLAG (SET or RESET).
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*/
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FlagStatus RNG_GetFlagStatus(uint8_t RNG_FLAG)
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{
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FlagStatus bitstatus = RESET;
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/* Check the parameters */
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assert_param(IS_RNG_GET_FLAG(RNG_FLAG));
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/* Check the status of the specified RNG flag */
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if ((RNG->SR & RNG_FLAG) != (uint8_t)RESET)
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{
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/* RNG_FLAG is set */
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bitstatus = SET;
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}
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else
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{
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/* RNG_FLAG is reset */
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bitstatus = RESET;
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}
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/* Return the RNG_FLAG status */
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return bitstatus;
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}
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/**
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* @brief Clears the RNG flags.
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* @param RNG_FLAG: specifies the flag to clear.
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* This parameter can be any combination of the following values:
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* @arg RNG_FLAG_CECS: Clock Error Current flag.
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* @arg RNG_FLAG_SECS: Seed Error Current flag.
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* @note RNG_FLAG_DRDY can not be cleared by RNG_ClearFlag() function.
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* This flag is cleared only by reading the Random number data (using
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* RNG_GetRandomNumber() function).
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* @retval None
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*/
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void RNG_ClearFlag(uint8_t RNG_FLAG)
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{
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/* Check the parameters */
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assert_param(IS_RNG_CLEAR_FLAG(RNG_FLAG));
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/* Clear the selected RNG flags */
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RNG->SR = ~(uint32_t)(((uint32_t)RNG_FLAG) << 4);
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}
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/**
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* @brief Checks whether the specified RNG interrupt has occurred or not.
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* @param RNG_IT: specifies the RNG interrupt source to check.
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* This parameter can be one of the following values:
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* @arg RNG_IT_CEI: Clock Error Interrupt.
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* @arg RNG_IT_SEI: Seed Error Interrupt.
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* @retval The new state of RNG_IT (SET or RESET).
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*/
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ITStatus RNG_GetITStatus(uint8_t RNG_IT)
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{
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ITStatus bitstatus = RESET;
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/* Check the parameters */
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assert_param(IS_RNG_GET_IT(RNG_IT));
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/* Check the status of the specified RNG interrupt */
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if ((RNG->SR & RNG_IT) != (uint8_t)RESET)
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{
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/* RNG_IT is set */
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bitstatus = SET;
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}
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else
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{
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/* RNG_IT is reset */
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bitstatus = RESET;
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}
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/* Return the RNG_IT status */
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return bitstatus;
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}
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/**
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* @brief Clears the RNG interrupt pending bit(s).
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* @param RNG_IT: specifies the RNG interrupt pending bit(s) to clear.
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* This parameter can be any combination of the following values:
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* @arg RNG_IT_CEI: Clock Error Interrupt.
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* @arg RNG_IT_SEI: Seed Error Interrupt.
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* @retval None
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*/
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void RNG_ClearITPendingBit(uint8_t RNG_IT)
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{
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/* Check the parameters */
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assert_param(IS_RNG_IT(RNG_IT));
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/* Clear the selected RNG interrupt pending bit */
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RNG->SR = (uint8_t)~RNG_IT;
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}
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/**
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* @}
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*/
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/**
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* @}
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*/
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/**
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* @}
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*/
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/**
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* @}
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*/
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/******************* (C) COPYRIGHT 2011 STMicroelectronics *****END OF FILE****/
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