Hi, thanks for you comments.
I need to read up a bit more on strcpy, snprintf and strncpy, I must admit, I just used them parrot fashion when looking at another example so thanks for pointing that out.
The 7bit value for editingBit was just an idea I had for representing the the position in a line of date data that looked like this :
Mon 03-04-2013 09:30:00
You were correct in saying it is a cursor, the 7 bits represent which of the above we are incrementing or decrementing. I thought that using a byte of data was neat as I could shift the pointer using the bit-wise operator, I could just as easily have used an integer I guess but coming form c# I don't get to use bits and bytes that often so this just seemed clever to me. Do you think I could have taken a better approach?
Must admit, I missed the scoping of buttonPressed, thanks for picking that up 
I'll check the data type of the time properties but I think your right and they are probably are unsigned.
Anyway, thanks so much for your time, it's really helpful to get some feedback as most of the time I'm the only one who sees my own code and in this early stage of learning it's really helpful to have nice people like you, Thank you