Feed
=========

Function description:
---------------------
    This **IWDG** shows how to reload the **IWDG** counter at regulate period.
    Configure wiwdgkr register to write **0x5555** to enable **IWDG_PR** and **IWDG_Access** authority 
    of RLR register, configure iwdgpr for pre frequency division, configure the loaded value 
    of RLR register, write **0xaaaa** to load **Kr** register, and then write **0xcccc** to start.

Test result:
------------
    Feed the dog 5 times in a row,if success printf pass,if not system reset.
    
IO connection:
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NONE