Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!uunet!van-bc!ubc-cs!fs1!fs1.ee.ubc.ca!jthornto
From: jthornto@fs1.ee.ubc.ca (THORNTON JOHAN A)
Newsgroups: comp.sys.handhelds
Subject: Re: general 48sx stuff
Message-ID: <1471@fs1.ee.ubc.ca>
Date: 7 Dec 90 19:23:36 GMT
References: <00940BEE.C00A4E80@pip.cc.brandeis.edu>
Sender: root@fs1.ee.ubc.ca
Reply-To: jthornto@fs1.ee.ubc.ca (THORNTON JOHAN A)
Organization: Dept. of Electrical Engineering University of B.C.
Lines: 42

In article <00940BEE.C00A4E80@pip.cc.brandeis.edu> st901745@pip.cc.brandeis.edu writes:
>3) I found a neat 'thingy' with the ON-D. I know it works on the REV C 
>and D calculators. Type ON-D  <- (backarow) ENTER 9 (the top row will 
>shift over a bit) type 9 again (screen gets dimmer) type 9 again (screen 
>will turn all black and slowly (depends on battery life) the screen will 
>"disolve." Once you are in this "mode" it is sorta hard to get out (you 
>must hit ON-C several times). I would like to know if this is bad for my 48SX?

Pressing ON-D, backspace, enter causes the memory scanner/editor to go to
address #00100h, which is where the HP48SX's display controller is.
 
  #00100h: bits 0-1 control the 4 pixel offset of the display.  Useful for
           smooth scrolling.  Bit 2 is also involved here but messes up the
           scan length.  Bit 3 seems to put the machine into a coma
  #00101h: LSBs of the 5 bit contrast control word.
  #00102h: bit 0 is the MSB of the contrast.  Bits 1 and 3 control the
           voltage difference across the LCD; this is what you modified.
           Can't see what bit 2 does.
  #00103h: bit 3 is also involved in the LCD voltage control.
 
  #0010Bh: bit 0,1,2,3: \<-, \->, alpha, and alarm indicators
  #0010Ch: bit 0,1: busy and I/O indicators; bit 3 must be set for the
           indicators to be on.
  #00120h - #00124h: display address base register.  Ususally set to #F097Ch
           (or #F09BC with the equation card installed) but you can change it,
           to look at any memory you want.  Note that you can't read this
           register, just write to it.  Remember to type addresses in
           backwards.
  #00125h - #00127: amount of overscan per pixel line
  #00128h : offset to menu area bitmap, normally 7.
  #00129h : bits 0-1 control the location of the menu area, normally 3.  Don't
           mess with bit 2, which can totally remap your calculator's display!
           ON-C does not fix what happens, but turning it off does, strangely
           enough.

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