[comp.sys.ibm.pc.hardware] Hercules 720x352 graphics mode dangerous?

dwennick@polari.UUCP (don wennick) (11/24/90)

In a nutshell, is there any danger of frying a monitor and/or Herc
card by forcing 350 lines in graphics mode? I've already got it working
on my machine, but don't want to distribute it if it's potentially
deadly...

You see, I want to simulate text mode in graphics mode, and to do that
it really takes 350 lines to be exactly the same. I've changed the
usual 348 line setup as follows:

Register	Normal		Modified
--------	------		--------
4 (Tot Vert)	 0x5B		  0x5C
5 (Vert Adj)	 0x02		  0x04
6 (Vert Dsp)	 0x57		  0x58
7 (Vert Sync)	 0x57		  0x58

This looks good on the screen, and is indistinguishable from text mode,
except that the cursor isn't done in hardware & I'm not going to make
it blink. Also, of course, this yields 352 lines.

So, 6845 wizards, is this going to gradually destroy my display? Is there
a way to do this safely? And did that Vertical Adjust need changed at all?

Thanks,
Don.

-- 
Don Wennick | dwennick@polari.UUCP -or- donw@rwing.UUCP
"subhuman bloodless leaders fed on lies and fear / and TV anchor news teams
 trim all we see and hear / use your head / sidestep the traps / snake
 through the chaos with a smooth noodle map" - Devo


-- 
Don Wennick | dwennick@polari.UUCP -or- donw@rwing.UUCP
"subhuman bloodless leaders fed on lies and fear / and TV anchor news teams
 trim all we see and hear / use your head / sidestep the traps / snake
 through the chaos with a smooth noodle map" - Devo