Clock gating on Tiva Launchpad
Lets convert all of your integer values to binary for easier comparison.

    0x20 -&gt; 0b00100000
    5    -&gt; 0b00000101
(5 &lt;&lt; 1) -&gt; 0b00001010


I think you can already see the problem.

If, however, you did (1 &lt;&lt; 5) instead, you'd have:

    0x20 -&gt; 0b00100000
    1    -&gt; 0b00000001
(1 &lt;&lt; 5) -&gt; 0b00100000


So, to sum it up, you need to shift 1 left by 5 bits, not shift 5 left by 1 bit.