hull@hao.ucar.edu (Howard Hull) (11/03/90)
Ok, on the one hand I have this first article - ref1:Message-ID: <615@medusa.informatik.uni-erlangen.de> ref1:Date: 28 Nov 89 12:32:00 GMT ref1:Organization: IMMD IV, University of Erlangen, W-Germany ref1: ref1:bobl@pro-graphics.cts.com (Bob Lindabury) writes: ref1: ref1:>toggle switch to jumper J102 and toggle between PAL and NTSC video (when ref1:>powered off) and view the demo in it's full glory. ref1: ref1:mlelstv@immd4.informatik.uni-erlangen.de (Michael van Elst) replies: ref1:Switching between PAL and NTSC while still *POWERED ON* successfully ref1:D A M A G E S the chip. ref1: ref1:Just a warning. ref1: ref1: Michael van Elst ref1: ref1:E-mail: UUCP: ...uunet!unido!fauern!immd4!mlelstv ref1: and on the other hand, I have this second article - ref2:Message-ID: <1990Oct31.091918.9584@canterbury.ac.nz> ref2:Date: 30 Oct 90 20:19:17 GMT ref2:Organization: University of Canterbury ref2: ref2:thomas@DS.HUJI.AC.IL (Shimko Thomas) writes: ref2:> I have built this switch that connects to a leg of Super Agnus via one ref2:>of the ref2:> jumpers. I would like to know if any damage can be made to my Amiga if ref2:>I switch ref2:> the Amiga from Pal to Ntsc or vice versa, without powering down. Of ref2:>course the ref2:> change takes place only at reboot. I just want to save my Amiga from any ref2:> uneccesary powerdowns possible. Many thanx for proffesional views. ref2:>Better reply ref2:> by mail. ref2: ref2:chem194@canterbury.ac.nz (John Davis, programmer at large, chemisry department) replies: ref2:A few people here have done that mod, and it seems to be perfectly ok ref2:to toggle the switch and reboot, without powering down. ref2: ref2:Of course, you can always do the same thing via software - have a look ref2:at BootMenu and Kill2090 on abcfd20 ( what! me push my own packages, you ref2:bet :-) ref2: ref2:----------------------------------------------------------- ref2:| o John Davis - CHEM194@canterbury.ac.nz o | ref2:| o (Depart)mental Programmer,Chemistry Department o | ref2:| o University of Canterbury, Christchurch, New Zealand o | ref2:| o o | ref2:| o co-sysop AmigaINFO BBS,1200/2400 baud CCITT, o | ref2:| o 24 hours a day, ph NZ +3-3371-531 o | ref2: Now then, are these two articles paid political announcements, or what? With respect to the second article, I _know_ that the statement "Of course, you can always do the same thing via software - have a look at BootMenu and Kill2090 on abcfd20 ..." needs a block of salt if the Amiga has 1 megabyte of chip ram and a CBM A2620 card with 2 megabytes of 32-bit memory, since the software in question must reset the protected soft ROM NTSC/PAL flag _after_ warm reboot rather than before; thus do I wonder if what it says about the switch is all of the time for some of the Amigas, or some of the time for all of the Amigas... Are these two articles refering to the same mod (J102), or is there some other mod, and if so, what is the one that won't fry the machine? Does anybody out there know for sure? Where did the thread about frying the machine come from, anyway? Howard Hull hull@ncar.ucar.edu
chem194@canterbury.ac.nz (John Davis, programmer at large, chemistry department) (11/04/90)
In article <9063@ncar.ucar.edu>, hull@hao.ucar.edu (Howard Hull) writes: > Ok, on the one hand I have this first article - > > ref1:D A M A G E S the chip. > ref1: > ref1:E-mail: UUCP: ...uunet!unido!fauern!immd4!mlelstv > ref1: > > and on the other hand, I have this second article - > > ref2:chem194@canterbury.ac.nz (John Davis, programmer at large, chemisry department) replies: > ref2:A few people here have done that mod, and it seems to be perfectly ok > ref2:to toggle the switch and reboot, without powering down. > ref2: > ref2:Of course, you can always do the same thing via software - have a look > ref2:at BootMenu and Kill2090 on abcfd20 ( what! me push my own packages, you > ref2:bet :-) > Now then, are these two articles paid political announcements, or what? > With respect to the second article, I _know_ that the statement > "Of course, you can always do the same thing via software - have a look > at BootMenu and Kill2090 on abcfd20 ..." > needs a block of salt if the Amiga has 1 megabyte of chip ram and a CBM > A2620 card with 2 megabytes of 32-bit memory, since the software in question > must reset the protected soft ROM NTSC/PAL flag _after_ warm reboot rather > than before; actually, the only requirement for software switching NTSC/PAL is the 1mb Agnus - there is NO requirement for MMUs or anything else. BootMenu and Kill2090 use the mechanisms for writing reset survivable programs that have been in the o/s from the beginning ( this is how rad: works - and a lot of viruses also ). In fact, if you are using a MMU equipped machine and SetCPU there is the proviso that you MUST invoke bootmenu before setcpu ( as I need to get at the _physical_ memory for the systemstack - a bug on my behalf that I hope to fix in the next version ). Also the NTSC/PAL register is in NO WAY protected - you can quite happily toggle it at any time, and the video will toggle correspondingly. This isn't much use with wb1.3 ( video mode will change but the system copper list won't reflect it - gives kind of interesting displays ) but WB2.0 uses it to allow user choice of screen mode via preferences on the fly. Now, since wb2.0 switches NTSC/PAL on the fly that implies to me that toggling the register DOESN'T hurt the chip - certainly I've seen no evidence to support the assertion that you can hurt the hardware by doing so. I guess there are some monitors that won't like one of the two video standards, but my 1084s seems equally happy with either. > thus do I wonder if what it says about the switch is all of the > time for some of the Amigas, or some of the time for all of the Amigas... > Are these two articles refering to the same mod (J102), or is there some > other mod, and if so, what is the one that won't fry the machine? Does > anybody out there know for sure? Where did the thread about frying the > machine come from, anyway? > Howard Hull > hull@ncar.ucar.edu As far as I can tell we're all talking about putting a simple open/closed switch across j102 - it's the only hardware ntsc/pal toggle point I know of ( documented on the sheet for fitting the 1mb agnus ). Since the hardware seems explicitly set up to only look at the jumper state on reboot only, I find it hard to believe toggling the line state is going to do any harm. The software method _has_ to be safe as CBM themselves do it in wb2.0. My observations have been that both the hardware and software solution work fine and cause no problems (I'm actually running my machine in NTSC mode at this very moment ) - maybe someone at CBM can give us the definitive answer ... ----------------------------------------------------------- | o John Davis - CHEM194@canterbury.ac.nz o | | o (Depart)mental Programmer,Chemistry Department o | | o University of Canterbury, Christchurch, New Zealand o | | o o | | o co-sysop AmigaINFO BBS,1200/2400 baud CCITT, o | | o 24 hours a day, ph NZ +3-3371-531 o |
hull@hao.hao.ucar.edu (Howard Hull) (11/12/90)
Well, John Davis posted the only comment I've received on this. I have thus come to the conclusion that it must be safe with an Amiga 500 or 2000 that has the 1Meg Agnus installed to add a switch across J102 and to change that switch while power is on (though as John points out, it will not likely be detected until the next reboot). I am also somewhat convinced that the origin of the posted warning articles may be with respect to the old 512K Agnus used in many yet-in-use earlier Amiga 500 and 2000 machines that have 512K of chip RAM and 512K C00000 of "slow fast RAM." It is possible that some of these users (maybe even with the 1 meg Agnus on hand but not yet installed in the machine) began making the mods with the NTSC/PAL switch mod first. If you intend to both install a 1 Meg Agnus and add the NTSC/PAL switch, and you want to check things out in steps, I recommend that you put the 1 Meg chip in before you add the J102 switch, just based on the peculiar origin of the warnings posted last year. That's all folks... Howard Hull hull@ncar.ucar.edu