/** @page CLK_ClockSelection How to select the different clock sources
  @verbatim
  ******************** (C)COPYRIGHT 2014 STMicroelectronics *******************
  * @file    CLK/CLK_ClockSelection/readme.txt
  * @author  MCD Application Team
  * @version V2.0.4
  * @date    26-April-2018
  * @brief   This file contains the description of Clock Selection example.
  ******************************************************************************
  *
  * 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.
  *
  ******************************************************************************
  @endverbatim

  @par Example description

  This example demonstrates the possibility to select the different clock sources 
  using the joystick available on the evaluation board.
  - To select a clock source, push the joystick in the corresponding direction. 
    UP = HSE, DOWN = LSI & LEFT = HSI
  - The current clock selection will be displayed on the LCD.
  - Current clock source can be visualized on CCO pin. 
  


  @par Directory contents

  - CLK\CLK_ClockSelection\main.c         Main file containing the "main" function
  - CLK\CLK_ClockSelection\stm8s_conf.h   Library Configuration file
  - CLK\CLK_ClockSelection\stm8s_it.c     Interrupt routines source
  - CLK\CLK_ClockSelection\stm8s_it.h     Interrupt routines declaration
  

 @par Hardware and Software environment

  - This example runs on STM8S and STM8A High density, Medium density and Low 
    density devices.
  
  - This example has been tested with STMicroelectronics STM8/128-EVAL evaluation 
    board and can be easily tailored to any other development board.

  - STM8/128-EVAL Set-up
      - LCD 
      - Joystick UP, DOWN, RIGHT

  
  @par How to use it ?

  In order to make the program work, you must do the following :

  - Copy all source files from this example folder to the template folder under
    Project\Template
  - Open your preferred toolchain 
  - Add the required file:
    - stm8s_eval_lcd.c  (under Utilities\STM8S_EVAL\Common)
  - Rebuild all files and load your image into target memory
  - Run the example
  - Using the joystick choose the desired clock source to apply:
    UP = HSE, DOWN = LSI & RIGHT= HSI
  - A message is displayed on the LCD to indicate the currently used clock.
  - The clock switching can be monitored by putting a scope on PE0 (CCO).


  @par Hint
  
  - Before using the HSE clock make sure that the "Flash_Wait_States" is set to 1.
  - Before using the LSI clock you have to configure the option bytes in order 
    to enable the "LSI_EN".
  - To do so :
    - with STVD (menu: Debug Instrument -> MCU configuration -> Options -> 
                 LSI_EN = Enabled
                 Flash_Wait_States = 1)
    - with RIDE (edit the "STM8_OB.asm" file to configure the OPT3 & NOPT3 
                 OPT7 & NOPT7 option bytes)
    - with EWSTM8 (menu: ST-LINK -> Option bytes -> 
                   LSI_EN = Enabled
                   Flash_Wait_States = 1)    
  
 
  @note
  - High-Density STM8A devices are the STM8AF52xx STM8AF6269/8x/Ax,
    STM8AF51xx, and STM8AF6169/7x/8x/9x/Ax microcontrollers where the Flash memory
    density ranges between 32 to 128 Kbytes
  - Medium-Density STM8A devices are the STM8AF622x/4x, STM8AF6266/68,
    STM8AF612x/4x, and STM8AF6166/68 microcontrollers where the Flash memory 
    density ranges between 8 to 32 Kbytes
  - High-Density STM8S devices are the STM8S207xx, STM8S007 and STM8S208xx microcontrollers
    where the Flash memory density ranges between 32 to 128 Kbytes.
  - Medium-Density STM8S devices are the STM8S105x and STM8S005 microcontrollers
    where the Flash memory density ranges between 16 to 32-Kbytes.
  - Low-Density STM8S devices are the STM8S103xx, STM8S003, STM8S001 and STM8S903xx microcontrollers
    where the Flash density is 8 Kbytes.
      
 * <h3><center>&copy; COPYRIGHT STMicroelectronics</center></h3>
 */
