Sdcard_copy
===========

Function description:
---------------------
This demo shows copying files on **SDCard** via **SDIOn**.

Test result:
------------
If the terminal displays the desired print and the file is successfully copied as filename cp.txt, 
the execution is considered successful, otherwise it fails.

IO connection:
--------------
+-----------------+------------------+
| PAD             |    PAD           |
+=================+==================+
| pad_sdion_sdclk |    sdcard_clk    |
+-----------------+------------------+
| pad_sdion_sdcmd |    sdcard_cmd    |
+-----------------+------------------+
| pad_sdion_sddat0|    sdcard_dat0   |
+-----------------+------------------+
| pad_sdion_sddat1|    sdcard_dat1   |
+-----------------+------------------+
| pad_sdion_sddat2|    sdcard_dat2   |
+-----------------+------------------+
| pad_sdion_sddat3|    sdcard_dat3   |
+-----------------+------------------+

.. Note::
    * The 'n' in "sdion" indicate the peripheral number.
    * An **SDCard** in FAT32 format should be prepared first.
    * There is a file named fatfs.txt on **SDCard**.