user19972: I need to load the Atmega328p 8kHz board definition using the board manager and can not find a way.  Any help will be appreciated.

user19409: Assuming that you have a 3.3V Atmega328P and are using an external 8MHz occilator: 
In the Arduino IDE click on Tools.
Scroll down until you see an option starting with the word Board:
Select the option called Arduino Pro or Pro Mini 
Click the Tools menu once again.
This time select the option starting with Processor:
Select the Atmega328P (3.3V, 8MHz)
Done!
Alternatively you can edit the boards.txt file located somewhere similar to C:\Program Files (x86)\Arduino\hardware\arduino\avr
Fuse bits can be calculated using one of these online tools:  

http://www.engbedded.com/fusecalc/ 
http://eleccelerator.com/fusecalc/


19972: <p>I need to load the Atmega328p 8kHz board definition using the board manager and can not find a way.  Any help will be appreciated.</p>
 19409: <p><strong>Assuming that you have a 3.3V Atmega328P and are using an external 8MHz occilator:</strong>  </p>

<p>In the Arduino IDE click on <code>Tools</code>.<br>
Scroll down until you see an option starting with the word <code>Board:</code><br>
Select the option called <code>Arduino Pro or Pro Mini</code>  </p>

<p>Click the <code>Tools</code> menu once again.<br>
This time select the option starting with <code>Processor:</code><br>
Select the <code>Atmega328P (3.3V, 8MHz)</code><br>
Done!</p>

<p>Alternatively you can edit the <code>boards.txt</code> file located somewhere similar to <code>C:\Program Files (x86)\Arduino\hardware\arduino\avr</code><br>
Fuse bits can be calculated using one of these online tools:  </p>

<ul>
<li><a href="http://www.engbedded.com/fusecalc/" rel="nofollow noreferrer">http://www.engbedded.com/fusecalc/</a>  </li>
<li><a href="http://eleccelerator.com/fusecalc/" rel="nofollow noreferrer">http://eleccelerator.com/fusecalc/</a></li>
</ul>
