n233dk@tamuts.tamu.edu (Rick Grevelle) (10/15/90)
I was hoping someone, perhaps at HP, could tell me what in the world happens to the display when the following key strokes are executed? It looks quite disturbing, but seems to have no ill consequences; I've always believed that in order to destroy my calculator, it would have to be done in ways that are not readily available through user keys. Rick Grevelle i) Enter the memory scanner: [ON] [D], [back arrow] ii) Go to address #00100: [ENTER] iii) Melt the dispaly: [A], [B], [C] iv) Restore after melt: [ON] [C]
frechett@boulder.Colorado.EDU (-=Runaway Daemon=-) (10/15/90)
I too have played with thhe "melting display" and I can't figure out any nice way of doing this in a purely electro-physical sense. The pixels are not turning on and off... They look like they are dying.. sort of when you press real hard on your favorite casio screen.... ;) I have found that with the right combinations I have had it melt in just a few seconds or really take its time slowly disolving the screen. I do notice that it take a little longer to come to full clarity when I do hit ON-C to recover. Especially if I hit it right after the A B C sequence (or A A A B B B C C C etc.... ). Mine generally starts at the left side of the screen and starts to fade out into the rest. Is this global, or do other people's do it differently? I would also love to here how and why this is done. ian -- -=Runaway Daemon=-
maksymc@jacobs.CS.ORST.EDU (Chris Maksymiak) (10/15/90)
Ok... This is a first atempt at posting so: #include <stddisclaimers.h> ok, I thought this was rather interesting so I promptly picked up my 48 and tried what was discribed... immediately the whole screen went blue, so I did the [ON]-C to clear it... I saw a very interesting thing happen to the display-- it flickered and melted into a parabolic shape on center-left side of the display... I was curious to know if anyone else had this happen... Also, I am looking for info... Anyone else try a [ON]-[SPC]?? I found it will do this: Beep at you (even if beeper is set to off), then display verticle bars on the left side of the screen, then turn off. When turned back on, it will show the screen, blank the display, then take its time getting the display back on... (sortof like a system halt immediately after turning it on) So my question is, anyone know what the hell this [ON]-[SPC] does exactly (internally)? And one request... I assume that people have picked this apart but could a few kind soles email me with a discription of the [ON]-D commands? I would really like to know just what I am doing. I have heard of a internal debugger which I would like to know how to use. Any info would be apreciated. I have one suggestion regarding all the flames about the "me-too" postings. I think that if someone asks for info and someone else wants it too, that they should email the person who asked for the info in the first place. (ie: if anyone is insanely curious about the info I requested, they should email me with a "me-too" instead of posting it...) Well, enough flames... -- Chris -- maksymc@jacobs.cs.orst.edu -- maksymc@128.193.32.13
djf@merit.edu (David J. Fred) (10/15/90)
In article <9095@helios.TAMU.EDU> n233dk@tamuts.tamu.edu (Rick Grevelle) writes: > >I was hoping someone, perhaps at HP, could tell me what in the world happens >to the display when the following key strokes are executed? It looks quite >disturbing, but seems to have no ill consequences; I've always believed that >in order to destroy my calculator, it would have to be done in ways that are >not readily available through user keys. [ . . . ] >ii) Go to address #00100: [ENTER] > [ . . . ] I don't know whether I'd call use of a, more or less, undocumented hex editor "readily available through user keys" ;-) But I know what you mean. After using bigger computers for quite a while now, it's nice to have such control of an environment, though it is potentially dangerous... As I remember, from a c.s.h posting of a couple months ago, there are several LCD hardware control registers at, or around, #00100. According to this article there were some values for these registers that could theoretically damage the display. (something about DC bias, or a test mode?) Therefore, until someone "in the know" says it's harmless; it seems it *might* not be a great thing to grab the calculator and try... -- David J. Fred / djf@merit.edu Merit/NSFNET Network Operations Center "Do warnings need disclaimers?" -- -- David J. Fred Merit/NSFNET Network Operations Center djf@merit.edu University of Michigan, Ann Arbor, MI
prestonb@hpcvra.CV.HP.COM (Preston Brown) (10/15/90)
The melting is caused by messing up the drive voltages going to the display. The system control registers start at #00100h and you are poking invalid codes into the display voltage control registers. The effect is caused by putting a large DC voltage across the pixels in the display. The LCD material responds well to the low AC voltage normally used but a large DC voltage produces the effect you see. If you leave the DC voltage on the display for long periods it may cause a reliability problem. The [ON]-C corrects the control registers and restores the proper voltages. Preston
maksymc@jacobs.CS.ORST.EDU (Chris Maksymiak) (10/17/90)
Soon after my posting, I managed to get a copy of Alonzo
Gariepy's "Intro to the 48's Internals"... after learning how to
use the memory scanner, I played around with (ya, real stupid, huh?)
the #00100h area adresses... In the first nibble, the 8 seems to
turn the display off (along with the basic keys, not the [on]-??
ones though -- [on]-c will work...)... by placing a 9 through A
in that position instead, one can shift the display to the left
X-8 pixels (where X is what you put in)... anything higher will
do some strange things to the display characters... (anyone have
a guess?) I found that the #00101h address is just a nibble
representing your contrast level (put a larger one in for a higher
contrast)...
Question: anyone know a way to exit the memory scanner
without a [on]-c or a [on]-[spc]? btw, the [on]-[spc] is guessed
to be the way to enter the "coma mode"---don't ask me what this is..
(guess by Alonzo...) I found a very strange "real" located at
#1017Bh SYSEVAL ... it turns out to be: -5.72874767606E2:8
yes, it has a ':' in the exponent... I found that if you divide
it by itself, you don't get one, you get 1.1516... any ideas?
well.. enough comments...
If anyone is curious, I got four requests ("me-too's") for this
info (sent out copies of the innards file) by some people that
think that it was a good idea for email-"me-too's" instead of
posting... But I didn't get a single response with any info...
interesting...
-- Chris Maksymiak
-- maksymc@jacobs.cs.orst.edu
-- maksymc@128.193.32.13sburke@jarthur.Claremont.EDU (Scott Burke) (10/17/90)
In article <9095@helios.TAMU.EDU> n233dk@tamuts.tamu.edu (Rick Grevelle) writes: > >I was hoping someone, perhaps at HP, could tell me what in the world happens >to the display when the following key strokes are executed? It looks quite >disturbing, but seems to have no ill consequences; I've always believed that >in order to destroy my calculator, it would have to be done in ways that are >not readily available through user keys. > >Rick Grevelle > It seems appropriate to relate a similar encounter I had recently with my 48SX involving a melting screen... However, I didn't do it through the user keys. Instead, I dropped mine in a sink full of water :-0 I pulled it out, and the screen appeared to be dripping blue stuff (you know, like those sand painting things?) Looked pretty neato. Then the 48SX started buzzing and whirring, so I decided it was about time to take out my RAM card and EQLIB card, and perhaps the batteries as well. What great fun--don't try this at home!! The next day I casually sidled over to one of the 48's engineers and asked him if they had ever tried a submerge test... ;-) Got a blank look out of him, until I displayed my new form of modern art--an HP-48 etch-a-sketch. Scott.
n233dk@tamuts.tamu.edu (Rick Grevelle) (10/17/90)
In article <21051@orstcs.CS.ORST.EDU> maksymc@jacobs.CS.ORST.EDU (Chris Maksymiak) writes: > > I found a very strange "real" located at #1017Bh SYSEVAL ... > ... it turns out to be: -5.72874767606E2:8 > yes, it has a ':' in the exponent... I found that if you divide > it by itself, you don't get one, you get 1.1516... any ideas? > > Chris Maksymiak Sorry about this, but what you have found is not a real. Actually this is a very common mistake made by hackers. You see the five nibbles, #02922h, are part of the machine instruction located at #10179h. More specifically, it's #10179h: 3433920 move.p5 #02933h,c where this instruction moves the five nibble length constant #02933h from the instruction stream to register C beginning with the nibble pointed to by the register P. Which if you look at the previous instruction at #10177, should be #10177h: 21 move 1,p ; P points to nibble 1 such that register C should look like +---+- - - -+---+---+---+---+---+---+ | | | 0 | 2 | 9 | 3 | 3 | | +---+- - - -+---+---+---+---+---+---+ Simply by flagging down all of the occurrences of a prolog is no guarantee what you find is indeed the start of an object or the beginning of a program. As in the case above, they are used quite regularly within the instruction stream of the various machine routines located through out the 48's ROM. SYSEVALing prologs such as these can sometimes trash your user memory, including any memory held in any RAM cards that might happen to be plugged in at the time. Rick Grevelle