Opad_it
=======

Function description:
---------------------

This demo shows how to trigger **hmac opad key input request interrupt**.

* Enable global interrupt & register **HASH** interrupt.
* Enable the related interrupt.
* Configure the **HMAC** and start hmac operation, including short key that is less than one block size & long key that is greater than one block size test. after enable the hmac and write fifo normally will trigger the interrupt.
* Waiting trigger the related interrupt and enter interrupt serve function.

.. note::
    Using packaged function: **HMAC_SHA224** to realize hmac opearion, more information to see the comments about the function. 

Main configuration:
-------------------

=============  ========  =========  =============
  Algorithm      Mode       DMA       Data Type  
-------------  --------  ---------  -------------
   sha224        hmac     disable      no swap
=============  ========  =========  =============

Test result:
------------

If successfully trigger and enter interrupt service routine, then print pass, if not print fail.

IO connection:
--------------

None