Path: santra!tut!sunic!uupsi!rpi!zaphod.mps.ohio-state.edu!samsung!cs.utexas.edu!asuvax!ncar!mephisto!prism!gt1246c
From: gt1246c@prism.gatech.EDU (Warren Furlow)
Newsgroups: comp.sys.handhelds
Subject: HP-48 memory scanner
Message-ID: <6639@hydra.gatech.EDU>
Date: 4 Mar 90 06:57:17 GMT
Reply-To: gt1246c@prism.gatech.EDU (Warren Furlow)
Distribution: comp.sys.handhelds
Organization: Georgia Institute of Technology
Lines: 54

The HP-48SX is GREAT!  I think this machine is what the 28 should have been.
I would have been very disappointed with a fold out design.  One neat thing
is it can display a running clock while on.  The rubber feet are cleverly
designed so they are inserted into deep slots and require no glue.  I 
discovered this while looking for the disassembly screws.  Apparently
this machine has the same 'factory sealed' assembly as the 28 and cannot be 
taken apart without mangling it.  Very annoying.

Anyway, I have found a memory scanner and would like to pass on the 
details of it.

The memory scanner is activated as follows:
Go into test mode:  Press and hold ON, press D, release ON.
Press backarrow.  You should now see something in the following format:
AAAAA:DDDDDDDDDDDDDDDD
The AAAAA is the 5 hex digits of the address and the DD..D is the 16 hex 
digits of the data starting at that address.

The following keys cause the following actions:

KEY          Address
1/X          F0A8C:0000000000000000  (apparently a constant)
DEL          C0000:7B7B7B7B7B7B7B7B  (apparently a constant)
EEX          80000:7B7B7B7B7B7B7B7B  (apparently a constant)
+/-          F000A      (data changes)
ENTER        00100:8x00yyyy04008EC0  
             This one is especially interesting.  Each time ENTER is pressed,
             yyyy changes randomly, it would appear.  x changes but I don't 
             know when.  The rest seems to be a constant.  The real interesting
             stuff happens when one of the softkeys is pressed.  D, for 
             instance, screws up the pixels of the displayed data on the first
             press, darkens the contrast on the second and on the third, causes
             a cool screen fade.  The screen starts out all dark, and gradually
             lightens starting from the left.  Looks neat anyway.
EVAL         Displays the version number and copyright notice

up arrow     +1000h      (pressing and holding any of the following causes
down arrow   -1000h       them to auto repeat)
divide       -100h
multiply     +100h
subtract     +1
add          -1
decimal      +10h
0-9, softkeys, add  +1

SPC          auto scan mode +10 hex

Auto scan mode increments by 10 hex about 16 times a second.  
While in this mode, pressing the ON key halts the scan but may display
garbage since it looks like it does not always fully update the screen.
Pressing and holding ON, pressing MTH and then releasing ON will stop
the scan for 16 seconds.

To terminate test mode, press and hold ON, press C, release ON.