Re: Hmm double HIRES graphics on the ][e

[dalloff@freenet.columbus.oh.us (Dave Althoff)]

Using ][e Double Hi-Res Graphics The Hard Way--

a.  Do I have double hi-res graphics?
You do if you have a motherboard Revision B or later, AND you have the
extended 80-column card (or equivalent).  If you have the older version of
the extended 80-column card (the big one with the diagonal cut-out to
accommodate the ][e case lid), then you need a jumper over the pins on the
front end of the board (I used a little ball of tinfoil...)

b.  How do I display double hi-res graphics?
1.  Activate the 80-column display (PR#3)
2.  Bring up the hi-res graphics page (HGR).  Use Page #1 ($2000-$3FFF)
3.  Turn *OFF* game port anunciator #3 (POKE -16290,0)
    NOTE:  The official Apple documentation provided with the original
           Extended 80-Column Text Card manual got it wrong!)

Note that the normal Applesoft hi-res commands do NOT work on the
double-hi-res screen.  Like the 80-column screen, the display is
bank-switched.  The screen is divided up into groups of seven pixels as
follows...
(top line)
8192 8192 8193  8193  8194  8194  8195  8195  8196  8196  8197  8197
aux  main aux   main  aux   main  aux   main  aux   main  aux   main  
0-6  7-13 14-20 21-27 28-34 35-41 42-48 49-55 56-62 63-69 70-76 77-83

Determining which bank you are reading/writing to when accessing the
memory directly can be done with the hires page1/page2 switch.  For
instance, if you have a DHR picture on the screen and want to save it
under DOS 3.3, you can do this...

BSAVE MAIN BANK,A8192,L8187
POKE -16299,0
BSAVE AUX BANK,A8192,L8187
(you might need to do this in indirect mode (?CHR$(4);"BSAVE...") to keep
the page switch from getting thrown back to page 1)

To load the image, do this...
BLOAD MAIN BANK
POKE -16299,0:POKE -16299,0:REM Yes.  Do it twice.
BLOAD AUX BANK

And you should get the complete image.  There are other soft switches
which are better, along with some useful firmware routines, but I don't
know them...and simply using the PAGE1/PAGE2 switch has always worked for
me 8-)

--Dave Althoff, Jr.

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