ref: 6f14d3a3a15f85c47b1b146c5b82c21f015a4536
dir: /demos/stm32f429_disco/stm/stm32f4_spl/src/stm32f4xx_rng.c/
/**
******************************************************************************
* @file stm32f4xx_rng.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 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>© 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****/