View Full Version : MC6845 no vsync?

May 23rd, 2008, 02:39 PM

I've been having trouble for the past few weeks getting my MC6845P to world correctly. I loaded its 16 registers with data that should follow the timing in this chart that i made to fit VGA standards. http://i32.tinypic.com/51px75.jpg

H-sync outputs correctly, DE is correct. The only problem is that v-sync is ALWAYS low (and this is a problem). Anybody have thoughts as to why this isn't working? (I'm almost completely sure that the wiring is correct)