Horizontal scrolling text off by one pixel (row) when spanning near mid-panel

[Louis]

Take a look at this, and the rest of that thread:

Horizontal update tearing

I think this is caused by the multiplexing in the panel. There are two lines driven at a time, spaced 16 rows apart, and the code scans from top to bottom. If the line is going from right to left and moving one pixel left per frame, pixels (31,15) and (31,31) are lit just before pixels (30,0) and (30,16) are lit. Try rotating the screen in software before running the same code, you’ll likely see this go away or at least look different at rotations 90 and 270. Response to a similar report: Ma…