I'm working on a simple GPS implementation using a ublox neo 5q and a
freescale mcf51jm128.  The issue I'm having is that I only receive
intelligible NMEA data every now and again.  I have to reset the uC
firmware a couple times before I get an NMEA bitstream.

This bitstream may be seen in the first file I have attached "NMEA
Bitstream.jpg".

instead of this I get periodic unintelligible garbage which takes 3
forms of which one is a combination of X's and H's and may be seen in
the second file I have attached "garbage"

If anyone can offer me an explanation as to why this should be the case
it would be greatly appreciated.

Thanks in Advance