Configuration register - what happened to bit 4?

[rn.becker]

Looking in the documentation for configuration registers I see definitions for bits 0 through 15, except for bit 4.  That means the second nibble can have values 0, then 2-F from what I can tell.  Is there a definition for bit 4 being a 1?

Thanks in advance,

   Robert

[balaji.bandi]

Look at the cisco config register definations :

https://www.cisco.com/c/en/us/support/docs/routers/10000-series-routers/50421-config-register-use.html

hope this help you. 

[rn.becker]

Yes, I read that already.  Bit 4 is not defined.  I'm wondering if it has a purpose.

Thanks,

       Robert