One of those projects you knock up to get you out of a corner. Takes 1500 readings after trigger, with a 320 sample display scrolled display. Also offers a grab mode using NOPs to give reasonably accurate 1, 2, 4, 8, 16 or 32 uS inter read displays.
A cursor can slid across the display, set by a pot value, and "uS from trigger" is displayed, giving the opportunity to do some reasonably accurate measurements. Commercial quality pots give excessive jitter, and I suggest a 10 turn pot be used for setting the cursor. Cursor implementation is rather crude, as it is redrawn at every screen draw. It is done this way because of lack of a "get pixel" in the graphics lib, which would enable you to write functions to move a cursor across an existing plot without disturbing points already plotted.
Code and notes at excelworks.info