Initialization and de-initialization Functions
[HAL Exported Functions]

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              ##### Initialization and de-initialization functions #####
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   [..]  This section provides functions allowing to:
      (+) Initializes the Flash interface, the NVIC allocation and initial clock 
          configuration. It initializes the source of time base also when timeout 
          is needed and the backup domain when enabled.
      (+) de-Initializes common part of the HAL.
      (+) Configure The time base source to have 1ms time base with a dedicated 
          Tick interrupt priority. 
        (++) Systick timer is used by default as source of time base, but user 
             can eventually implement his proper time base source (a general purpose 
             timer for example or other time source), keeping in mind that Time base 
             duration should be kept 1ms since PPP_TIMEOUT_VALUEs are defined and 
             handled in milliseconds basis.
        (++) Time base configuration function (HAL_InitTick ()) is called automatically 
             at the beginning of the program after reset by HAL_Init() or at any time 
             when clock is configured, by HAL_RCC_ClockConfig(). 
        (++) Source of time base is configured  to generate interrupts at regular 
             time intervals. Care must be taken if HAL_Delay() is called from a 
             peripheral ISR process, the Tick interrupt line must have higher priority 
            (numerically lower) than the peripheral interrupt. Otherwise the caller 
            ISR process will be blocked. 
       (++) functions affecting time base configurations are declared as __Weak  
             to make  override possible  in case of other  implementations in user file.