If you're wondering why I've made no attempt to display higher resolution time, there are a few problems with that idea.

First, since the goal of this project is a human readable time display, there's no point at all in showing more than a tenth-of-a-second digit, since anything beyond that would just be a blur (and even displaying tenths of a second isn't really something people generally can make out). Some might suggest that even a hundredths digit might be useful for high speed video photography, but the problem with that is that the display multiplexes at about 625 Hz, so if you were to look at it that closely, you'd just see the digits all flickering.

But even trying to display a tenth-of-a-second digit is problematic, because there's no GPS synchronization signal beyond the PPS. The firmware would have to interpolate the tenths of a second, and it's running from a relatively inaccurate RC oscillator, so it wouldn't be nearly as accurate.