[comp.sys.apple] Video mods on a //c

nakada@husc4.HARVARD.EDU (Paul Nakada) (06/01/89)

someone mentioned a while back that the Laser line of apple // clones
has a modified video circuit which uses interlacing to eliminate the
distinct border between horizontal scan lines.  Apparently this is most
effective with a fairly high persistence monitor.  Well, is anyone out
there knowledgeable enough to give me a hand in doing this for my //c?

There is a video connector on the back panel of the //c which has
(i hope) all of the signals necessary for creating RGB or composite
signals.  I guess what i need to do is to somehow offset the second
refresh to fill in the gaps between scanlines...  If anyone feels
capable enough and willing to engage in a little email correspondece on
the topic, please write to me.  Then i can fill you in on the technical
stuff which you might need.   

Thanks very much.

-Paul Nakada

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|     Paul Nakada  '89   #8-)  |                                          
      North House              |                nakada@husc4.HARVARD.EDU  
      Harvard College          |       seismo>!harvard!husc4!nakada.UUCP  
      Cambridge, MA  02138     |     rutgers/   nakada@husc4.BITNET       
      617/498-6255 || 6264     |                                         __|

Sirald@cup.portal.com (Andrew Lionel Dalrymple) (06/02/89)

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Hello,

	A note regarding the LASER 128 mode of interlacing.
All you need to is at the machine language prompt (CALL -151)
type C025 to turn it on... and C024 to turn it off.  Someone
mentioned this to me a few months ago (thanks).

	Also, you could use the following boot program on
the Laser.  As the program boots, press CLOSED-APPLE to
turn the mode on... and when running the program again,
press OPEN-APPLE to kill the mode.

------------------------------------------------------------

 50 HOME
100 LA =  PEEK ( - 16287): IF LA > 127 THEN X =  PEEK
    ( 49188 ) : HOME : PRINT : PRINT : PRINT "
    P L A I N  t e x t  m o d e"
200 RA =  PEEK ( - 16286): IF RA > 127 THEN X =  PEEK
    ( 49189 ) : HOME : PRINT : PRINT : PRINT "
    S H I F T  t e x t  m o d e"


NOTE:  This won't look very good at all on screens that
       leave 'after-glow characters'... and it also will
       not look so hot in the 80col mode... although you
       can try.  I have found that using one of those
       polorizing anti-glare screen guards works GREAT!



Cordially,

   A. DALRYMPLE		sirald@cup.portal.com
			sun!portal!cup.portal.com!sirald
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