c60c-3ia@web-4d.berkeley.edu (02/06/91)
Days ago, I posted an article asking questions about HP-28S. There has been a fews responses, which I truly appreciates. Nevertheless, not all of my questions are answered, possibly because many people are no longer interested in HP-28S. But before can afford a HP-48SX in my next incarnation, I would like to use my HP-28S to its full potential. So I decide to give the following questions another chance: 1) Do the two books: "Custominzing you HP-28S" and "HP-28S insights" substitute or complement each other? If the answer is the former, which one is the better? 2) How on earth can one change the speed of a HP-28S? We know its pros and cons; now we want to try it ourselves/ 3) In one of the posted articles about HP internals, I remember seeing a warning that says improper use of SYSEVAL can result in memory loss or even hardware problem. I do not know how the later is possible. In addition, I have one more question for all experienced users: what can I do to prevent loss, theft, and damage to my HP-28S, especially when I bring it to the campus, where it is crowded and confusing? (For example, punch a hole on the upper part of the left-hand leaf and through it chain the calculator to my backpack or my wrist. I appreciate you answers.
akcs.dnickel@hpcvbbs.UUCP (Derek S. Nickel) (02/07/91)
1) Both books over some of the same material, however, "Custominzing you
HP-28S" contains information about the internals of the '28 that "HP-28S
insights" does not cover. You misght want both - they have very
different 'feels'
2) I don't have the code for speeding the '28 up, however it will drain
the batteries faster.
3) Some parts of the hardware are software controlled, such as a
prgrammable power supply (eek!)
4) use super glue to attach the '28 to your arm. Actually, I never had
any trouble at UC Berkeley...
Derek S. Nickelcloos@acsu.buffalo.edu (James H. Cloos) (02/07/91)
In article <1991Feb6.073911.25628@agate.berkeley.edu> c60c-3ia@web-4d.berkeley.edu writes: > >Days ago, I posted an article asking questions about HP-28S. There has >been a fews responses, which I truly appreciates. Nevertheless, not all >of my questions are answered, possibly because many people >are no longer interested in HP-28S. But before can afford >a HP-48SX in my next incarnation, I would like to use my HP-28S >to its full potential. So I decide to give the following questions >another chance: >[etc] OK, here is some more info. >3) In one of the posted articles about HP internals, I remember seeing a >warning that says improper use of SYSEVAL can result in memory loss or even >hardware problem. I do not know how the later is possible. >[etc] The hardware control registers are mapped in memory on the Saturn-based handhelds. (On the 48, these are ~100h, I forget where on the 28s, but the internals documentation would mention that.) If you poke bad data into those registers, hardware dammage can occur. One of these registers controls (to what degree I do not know) the voltage for the display. Too much, and "meltdown" occurs. This actually looks like the display is melting (not the physical hardware, mind you), and sustaining this can eventually cause damage to the display. The problem w/ sysevals is that if you try an address that is not an rpl object or prefixed machine code, or even try a valid address but w/ invalid arguments, whatever happens could include poking into the hardware control registers, thus the potential for actual, physical damage. This is onlt one example of what the registers control, there are others, but again, the internals docs should tell you what you need to know. >I appreciate you answers. Naturally. And the net appreciates your (plural) questions. ^- ;-) -^ ^--really--^ Seriously, though, that's what usenet what created for, ja? Oh, and for 28 stuff, check out gmuvax2.gmu.edu (via anonymous ftp) in the hp28 directory. Mget the files "processor*" and "rom*", also, greb "speed" for setting the calculator's speed. It's not the best version to have floated about on the net, but it does get the job done. -JimC -- James H. Cloos, Jr. Phone: +1 716 673-1250 cloos@ACSU.Buffalo.EDU Snail: PersonalZipCode: 14048-0772, USA cloos@ub.UUCP Quote: <>
jdg@hpqtdla.sqf.hp.com (James Gentles) (02/09/91)
In comp.sys.handhelds, c60c-3ia@web-4d.berkeley.edu writes: 2) How on earth can one change the speed of a HP-28S? We know its pros and cons; now we want to try it ourselves To put you out of your misery: From daemon%gmuvax2.gmu.edu@hplb.hpl.hp.com Tue Jan 16 17:02 GMT 1990 SPEED - SET SPEED OF CALCULATOR. THIS COMMAND WILL CHANGE THE SPEED OF THE 28S VERSION 2BB BY MODIFYING THE SPEED NYBBLE. SPEED ACCEPTS A VALUE FROM 0 TO 15, 7 BEING THE SYSTEM DEFAULT. IF BATTERIES ARE LOW, DO NOT CRANK UP THE SPEED TOO HIGH. SPEED SUFFERS FROM THE ANOMALY THAT THE SYSTEM MAY SET ITSELF BACK TO ITS DEFAULT UNEXPECTEDLY. PRESSING THE ON/ATTN KEY MAKES THE 28 REVERT BACK TO NORMAL SPEED. 15 IS ABOUT TWICE NORMAL SPEED, AND 0 IS ABOUT ONE-THIRD NORMAL SPEED. CHANGE SPEED DOES AFFECT BATTERY CONSUMPTION. 0 - 15 : CHK[532] << 'SPEED' -> S N ;S IS SPEED, N IS VAR NAME. << PATH RCWS ;SAVE PATH AND WORDSIZE ON STACK. 64 STWS ;SET WORDSIZE TO 64. S R->B #FH AND ;GET LEAST SIGNIF. NYBBLE. #1000000000000H * ;SHIFT LEFT INTO POSITION. #C600302331DFFBCH OR ;PUT NYBBLE IN PLACE. { # E60D51FFF00F1H ;THIS PROGRAM IS FORCED TO BE 1ST VARIABLE # C808461241131H } + ; IN ROOT DIRECTORY. HOME N RCL ;STORE ORIGINAL PROGRAM ON STACK. SWAP N PURGE N STO ;STORE MACHINE CODE AS 1ST VAR. #DFFB7H SYSEVAL ;EXECUTE CODE. N STO STWS CD ;RESTORE CALCULATOR STATE. >> >> Warnings: This program forces itself to be the first in the HOME directory. It must be typed in EXACTLY as above, YOU HAVE BEEN WARNED. There must be a 'better' version of this, however this one works. Speed may revert back to 7 at the calculators whim. Running at speeds above 7 may cause: 1. "Memory Lost" (especially with low batteries) 2. The battery low indicator to come on prematurely (I think the last two statements are a 'Strange Loop' :-) --------------------------------------------------------------------- I have no professional connection with Hewlett-Packard's calculator operations other than as a user of their products. --------------------------------------------------------------------- Opinions expressed are my own, and are not intended to be an official statement by Hewlett-Packard Company --------------------------------------------------------------------- Name: James Gentles GM4WZP Organization: Hewlett-Packard Queensferry Telecomunications Division Email: jdg@hpqtdla.hpsqf.hp.com hp-sdd Address: Station Road, South Queensferry, West Lothian, Scotland ---------------------------------------------------------------------