Random Number Generation on STM32F407

Hi All,

I want to be able to write a very simple program to generate random number using the RNG. Unfortunately I am extremely new to embedded programming and so please pardon my lack of knowledge. For the moment I have done the following :

a) Using the "Manage Run-Time environment" for my 407 discovery board i added support for the RNG by selecting it from the "Device -> STM32Cube Hal" list

b) Then I try to use the functionalities of the api by including the "stm32f4xx_hal_rng.h" file. I can see that this file has the API's that i should initialize

/* Initialization/de-initialization functions **********************************/
HAL_StatusTypeDef HAL_RNG_Init(RNG_HandleTypeDef *hrng);
HAL_StatusTypeDef HAL_RNG_DeInit (RNG_HandleTypeDef *hrng);
void HAL_RNG_MspInit(RNG_HandleTypeDef *hrng);
void HAL_RNG_MspDeInit(RNG_HandleTypeDef *hrng);

/* Peripheral Control functions ************************************************/
uint32_t HAL_RNG_GetRandomNumber(RNG_HandleTypeDef *hrng);
uint32_t HAL_RNG_GetRandomNumber_IT(RNG_HandleTypeDef *hrng);
void HAL_RNG_IRQHandler(RNG_HandleTypeDef *hrng);
void HAL_RNG_ReadyCallback(RNG_HandleTypeDef* hrng);
void HAL_RNG_ErrorCallback(RNG_HandleTypeDef *hrng);

However I dont know the proper way to use them. At best I have attempted the following.

Code

/*----------------------------------------------------------------------------
 * CMSIS-RTOS 'main' function template
 *---------------------------------------------------------------------------*/
#define osObjectsPublic
#include "osObjects.h"
#include <stdio.h>
#include <string.h>
#include "stm32f4xx_hal_rng.h"


/* main: initialize and start the system */
RNG_HandleTypeDef RngHandle;


int main (void) {

  osKernelInitialize ();

        RngHandle.Instance = RNG;
  HAL_RNG_MspInit(&RngHandle);

        if(HAL_RNG_Init(&RngHandle) == HAL_OK){
                uint32_t no = HAL_RNG_GetRandomNumber(&RngHandle);
        }
  osKernelStart ();

}

I put a breakpoint hoping to catch a value in 'no' but does not happen. Eventually i plan to push the value to the UART for display. I have tried that as well but again I would leave that to another discussion. For the moment I would just want to be able to get a random number from my hardware .

I saw this link as the only useful reference. github.com/.../rng.c

Please advise me any learning materials.