Higher resolutions with a Mega ST4
Christopher Friend
I've seen projects to fit an ET4000 ISA card into the ST but they seem way
too involved for me. Fitting the ST into a PC tower was one thing but I
think I could build a spaceship before I'd get the ET4000 project working
correctly.
Are there any alternatives?
Djordje Vukovic
On 27 May 2001 14:55:08 , "Christopher Friend" wrote:
>Does anyone know of anyway to increase the resolutions of a Mega ST4 system?
>I've seen projects to fit an ET4000 ISA card into the ST but they seem
>Are there any alternatives?
Well, yes.
There were once upon a time several graphic cards which could be
plugged into Mega's expansion port. Maybe you can find one.
However, from your post it appears that you are thinking of some
do-it-yourself approach. There are some possibilites here, too:
* The simplest hack would the "Overscan" which existed in several flavours,
ranging from a simple switch to a more sophisticated commercial product.
There is a simple (two chips) shareware version called "Lacescan". You can
achieve resoluton of 704 x 480 in ST-high with a well-adjusted SM-124
monitor, but in practice the figures can be slightly lower.
* A potentially most beneficial approach would be the one which involves
raising the clock frequency of the entire system to 10MHz or 12MHz.
Besides getting a noticeable acceleration of everything, this is supposed
to enable you to obtain resolutions of something like 800x500 (mono) or even
more on a SM-124 monitor- if you can get the sync rates right. There was an
article in a german computer magazine once (ST-computer, september+october
1992 ?), describing this modification, but it seems that today noone can
quote -exactly- the modification needed for video circuits. I have a general
idea of how it might work, but a tested schematics would be so much easier-
so if you find one let me know :)
cu.
Christopher Friend
>
>There were once upon a time several graphic cards which could be
>plugged into Mega's expansion port. Maybe you can find one.
>
>However, from your post it appears that you are thinking of some
>do-it-yourself approach. There are some possibilites here, too:
At this point anything that can raise the resolution/colors I'll take. With
something of this caliber I'd rather get something that will plugin and go
without too much work. I have looked at some of the overscan circuits on
Vezz's website and it seems that would be a good place to start. I'd also
like to put a 16MHz accelerator in but an 8MHz ST isn't that bad for most
stuff I use it for (games, light graphics)...I'd like to be able to use
stuff like Thing desktop but you need at least 16-colors to see the "beauty"
and 320x200 is very compromising when you are running a GUI :) Thanks for
the ideas...I'll look into them further.
Chris
Lyndon Amsdon
Hi
Overscan/lacescan or buy a PAnther from http://www.wrsdesign.de which is
the adaptor for ET4000 ISA graphics cards. Panther should be an easy fit
onto the megabus.
Or look out for an old Matrix card for the Mega ST. Best solution would
be the panther I feel.
Christopher Friend
>On 27 May 2001 14:55:08 , "Christopher Friend" wrote:
>
>Hi
>
>>Does anyone know of anyway to increase the resolutions of a Mega ST4
>system?
>>I've seen projects to fit an ET4000 ISA card into the ST but they seem way
>>too involved for me. Fitting the ST into a PC tower was one thing but I
>>think I could build a spaceship before I'd get the ET4000 project working
>>correctly.
>
>Overscan/lacescan or buy a PAnther from http://www.wrsdesign.de which is
>the adaptor for ET4000 ISA graphics cards. Panther should be an easy fit
>onto the megabus.
I looked at the Panther and that would be great as it would allow me VGA
video AND ethernet capabilities if I wanted them. Do you know if anyone at
WRS Designs speaks English? I no absolutely no german.
Another dumb question. The price of the adapter and an ET4000 graphics card
is 249,00DM... If that 24900 German Marks or 249 German Marks? With 249DM
equal to about $110 US I assume 249DM
Lyndon Amsdon
>>Overscan/lacescan or buy a PAnther from http://www.wrsdesign.de which is
>>the adaptor for ET4000 ISA graphics cards. Panther should be an easy fit
>>onto the megabus.
>
>I looked at the Panther and that would be great as it would allow me VGA
>video AND ethernet capabilities if I wanted them. Do you know if anyone at
>WRS Designs speaks English? I no absolutely no german.
Roland speaks English quite well, enough to be able to buy/sell. I've
bought many stuff from them and they're reliable, never had problems with
them.
>Another dumb question. The price of the adapter and an ET4000 graphics card
>is 249,00DM... If that 24900 German Marks or 249 German Marks? With 249DM
>equal to about $110 US I assume 249DM
Yeah, some countires use a comma instead of a full stop. It is 249DM, or
about 83 UKP. I never looked at the price, but I can tell you that's a
good price. They also sell PCBS only IIRC and recently they've added all
the GAL expressions ont he site so you can make your own Panther/PAK etc.
Pera Putnik
"Djordje Vukovic" <vdj...@EUnet.yu> wrote in message
news:9es588$1ot$1...@news.eunet.yu...
>
> On 27 May 2001 14:55:08 , "Christopher Friend" wrote:
> >Does anyone know of anyway to increase the resolutions of a Mega ST4
system?
> >I've seen projects to fit an ET4000 ISA card into the ST but they seem
> >[...]
> >Are there any alternatives?
>
> Well, yes.
>
> There were once upon a time several graphic cards which could be
> plugged into Mega's expansion port. Maybe you can find one.
>
> However, from your post it appears that you are thinking of some
> do-it-yourself approach. There are some possibilites here, too:
>
> * The simplest hack would the "Overscan" which existed in several
flavours,
> ranging from a simple switch to a more sophisticated commercial product.
> There is a simple (two chips) shareware version called "Lacescan". You can
> achieve resoluton of 704 x 480 in ST-high with a well-adjusted SM-124
> monitor, but in practice the figures can be slightly lower.
>
Yes, it is simple and cheap... I made it in 20 minutes & 2 $ cost.
But.... not much software can use it, and you need at least TOS 2.06 for
correct work.
> * A potentially most beneficial approach would be the one which involves
> raising the clock frequency of the entire system to 10MHz or 12MHz.
> Besides getting a noticeable acceleration of everything, this is supposed
> to enable you to obtain resolutions of something like 800x500 (mono) or
even
> more on a SM-124 monitor- if you can get the sync rates right. There was
an
> article in a german computer magazine once (ST-computer, september+october
> 1992 ?), describing this modification, but it seems that today noone can
> quote -exactly- the modification needed for video circuits. I have a
general
> idea of how it might work, but a tested schematics would be so much
easier-
> so if you find one let me know :)
>
Hmmm... I think that such projects are very hard for realize, even if you
find all ST magazines involved.
Btw. best Atari ST projects were in German CT magazine, you can still order
them on CD's from them: http://www.heise.de/ct .
PP
Matthias Jaap
> article in a german computer magazine once (ST-computer, september+october
> 1992 ?), describing this modification, but it seems that today noone can
> quote -exactly- the modification needed for video circuits.
Well, I have the magazines here and it was the ST-Magazin. I guess it worked
the same way as Overscan because Hyperscreen (as it was called in the
magazine) was made by the same people who created Overscan.
Greetings,
Matthias
Lyndon Amsdon
Hi
Is it possible for you to scan them in and send them to me please?
Djordje Vukovic
>> * The simplest hack would the "Overscan" which existed in several
>flavours,
> Yes, it is simple and cheap... I made it in 20 minutes & 2 $ cost.
Indeed. Though it seems Lacescan has a slight design flaw somewhere
in hardware or software: when it is switched off sometimes the screen
does not revert correctly to normal size, but a portion from the right
edge rolls to the left edge- so something was neglected. Otherwise
the roll-over would happen always or never.
>But.... not much software can use it,
I disagree very much! I have installed Lacescan in my Mega and have it
turned ON all the time. There are just a few older programs which can't
use it, but anything decently GEMish works OK. I remember, however
that some setting in NVDI-configuration CPX could make problems when
Lacescn was turned on- the menu bar was improperly drawn in some
programs.
>and you need at least TOS 2.06 for correct work.
Possibly. I use TOS 2.06 (in RAM for the moment) so I did not try it
much with older TOSes.
>> * A potentially most beneficial approach would be the one which involves
>> raising the clock frequency of the entire system to 10MHz or 12MHz.
>>[...]
>> noone can quote -exactly- the modification needed for video circuits.
>> I have a general
>> idea of how it might work, but a tested schematics would be so much
>> easier- so if you find one let me know :)
>>
>
> Hmmm... I think that such projects are very hard for realize, even if you
>find all ST magazines involved.
Not necessarily. I played a little with that project and for a start raised
the system clock to 10MHz (40MHz oscillator). By declaring external
syncs to TOS and by supplying the correct (or I thought so) sync pulses
obtained by dividing the 500kHz signal, I obtained a standard-resolution
picture on a SM-124. From that to an extended resolution it should not
be very difficult to go. (My attempt was not completely successful as the
picture trebmbled slightly (about 10 pixels) left-right, so I did not get
everything exactly right- or else at higher CPU speed the picture
started too early after a hsync pulse nd the monitor maybe couldn't
handle it). It was all done with several 74F and 74HCT chips.
I didn't have time to finish it, but I prepared some connections on
the motherboard to make everything more reliable, and will try again
with a modified circuit. My problem is finding reliable information
on pixel clock rates and line width- somehow the numbers I have do not
add-up correctly to 35.7Khz .
madmax
> On 27 May 2001 14:55:08 , "Christopher Friend" wrote:
>
> Hi
>
> >Does anyone know of anyway to increase the resolutions of a Mega ST4
> system?
> >I've seen projects to fit an ET4000 ISA card into the ST but they seem way
> >too involved for me. Fitting the ST into a PC tower was one thing but I
> >think I could build a spaceship before I'd get the ET4000 project working
> >correctly.
>
> Overscan/lacescan or buy a PAnther from http://www.wrsdesign.de which is
> the adaptor for ET4000 ISA graphics cards. Panther should be an easy fit
> onto the megabus.
I can't get the above link to work. Is it correct?
Later Brian
Christopher Friend
>> the adaptor for ET4000 ISA graphics cards. Panther should be an easy fit
>> onto the megabus.
>
>I can't get the above link to work. Is it correct?
It should be www.wrsonline.de
Lyndon Amsdon
>> Overscan/lacescan or buy a PAnther from http://www.wrsdesign.de which
>>is the adaptor for ET4000 ISA graphics cards. Panther should be an
>>easy fit onto the megabus.
>
>I can't get the above link to work. Is it correct?
Sorry Brian, http://www.wrsonline.de
Matthias Jaap
worked
> >the same way as Overscan because Hyperscreen (as it was called in the
> >magazine) was made by the same people who created Overscan.
>
> Is it possible for you to scan them in and send them to me please?
I will put them on stcarchiv.de which is an online magazine archive with the
permission by the publishers. It's the ST-Magazin 5/89. Their also a driver
program for Hyperscreen but I don't have the disk - only the listing in hex
code.
Greetings,
Matthias
Lyndon Amsdon
Hi
>> >Well, I have the magazines here and it was the ST-Magazin. I guess it
Cheers, tell me when you've pu them up.
Thanks!
Iggy Drougge
>>Another dumb question. The price of the adapter and an ET4000 graphics card
>>is 249,00DM... If that 24900 German Marks or 249 German Marks? With 249DM
>>equal to about $110 US I assume 249DM
>Yeah, some countires use a comma instead of a full stop. It is 249DM, or
>about 83 UKP. I never looked at the price, but I can tell you that's a
>good price. They also sell PCBS only IIRC and recently they've added all
>the GAL expressions ont he site so you can make your own Panther/PAK etc.
I see bare PCBs for the PAK and associated boards in their pricelist, but not
for the Panther. What a pity. Oh yes, what a pity for a starving student.
--
En ligne avec Thor 2.6a.
Amiga 4000/040 25MHz/44MB/20GB RetinaBLTZ3/VLab/FastlaneZ3/Ariadne/Toccata
Lyndon Amsdon
>>Yeah, some countires use a comma instead of a full stop. It is 249DM, or
>>about 83 UKP. I never looked at the price, but I can tell you that's a
>>good price. They also sell PCBS only IIRC and recently they've added all
>>the GAL expressions ont he site so you can make your own Panther/PAK etc.
>
>I see bare PCBs for the PAK and associated boards in their pricelist, but not
>for the Panther. What a pity. Oh yes, what a pity for a starving student.
Did you email them? They might do a deal, I don't know. I'm supprised
they don't do the PCBs for it.
Iggy Drougge
All right, I've sent a mail to them, I'll keep you informed.
--
En ligne avec Thor 2.6a.
Computer hackers do it all night long.