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ParanoidLittleMan

Monochrome emulator - still interesting, of use ?

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Considering that most of modern LCD/Flat screen monitors is capable of displaying Atari ST monochrome (high res.) video, with proper cable, I want to ask is SW monochrome emulation on color monitor/TV is still of interest ?

It gives not so sharp pic. , of course, and causes some slowdown too (on fly conversion). And I looked about what is available. Seen only Mick West's Mono Emu, versions from 1987 and 1988. I dealt with earlier one back in time (1988), and added new mode with 400 hor. lines, what gives sharper pic and faster work, but of course only half of pic is visible at once. As user moves mouse it will change pos. of visible part.  That was good in those years for some SW.  The bad thing is that it is tied for old. TOS versions 1.00 and 1.02 (only 1988 v.). And even lang. of TOS must be specific. I still have sources, so can update it for all TOS versions (well, not sure about 2.06 - that might be harder), and maybe to add it as option in TOS (1.04 and 1.62).   Depends of interest.

About cable for Atari ST monochrome to VGA: connect GND, Hor. and vert. signal lines directly, monochrome out to all 3 - R, G, B lines parallel. I did it via 1 18 Ohm resistor to prevent overdrive. And mono sensor line to GND. I guess hardest part in it is to find Atari 13 pin video connector.

It should work with  monitors with VGA input. In case of TVs - not sure. My 3 years old Philips (very good for ST color) has max refresh rate of 60 Hz, so monochrome works not. Little adjusting of screen size, pos. , and will be pretty fine.

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I almost forgot these things even existed!    I remember experimenting with them when I first got my ST,  they weren't great,  and since I also had a monochrome monitor, I didn't even need them.   I just liked to experiment with different software to see what my new ST could do.

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26 minutes ago, Goochman said:

I hooked my 1040 up to my SM124 last week and I forgot how gorgeous the display was.  So crisp :)

Mine died ☠️ , tried to fix it once, thought I found the problem, but still didn't work after the repair, my problem

is around the HT circuit, so a little awkward to poke around with 

 

I ended up making a VGA cable to a Dell LCD and use that in Mono, don't think it can do colour, am I right thinking

colour is a lower frequency ?

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I had SM124 too, around 2004, but did not use it much. 10 years later it did not work, and was not about to fix it - had LCD solution then.

Color is lower freq. Monitor need to support about 15 KHz scan rate  to be able to display ST color video (old TV frequencies) .

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Monochrome Display on SM124 was so great.   i would love to retrieve this kind of monochrome display on modern PC. 

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9 hours ago, youki said:

Monochrome Display on SM124 was so great.   i would love to retrieve this kind of monochrome display on modern PC. 

Resolutions are now much higher.  640x400 px versus now typical 1920x1080px . So big res. is very hard to solve quality with analog technology, and that would cost a lot.

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1 hour ago, ParanoidLittleMan said:

Resolutions are now much higher.  640x400 px versus now typical 1920x1080px . So big res. is very hard to solve quality with analog technology, and that would cost a lot.

What i would love is real monochrome display.   i would love a 1920x1080 in real monochrome. (not shade of grey) ... just as the Atari St or the first Mac were...  Pixel can be White or Black nothing else.

It was so comfortable to work with.   (of course we need application designed for that mode)

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13 hours ago, ParanoidLittleMan said:

Considering that most of modern LCD/Flat screen monitors is capable of displaying Atari ST monochrome (high res.) video, with proper cable, I want to ask is SW monochrome emulation on color monitor/TV is still of interest ?

actually, as my LCD works fine with ST-LOW through VGA, I'm more interested in having a possibility to switch resolution to any available. e.g. from color to mono and and vice versa.

Now in the Desktop preferences, in color mode, ST High is disabled and in Mono mode ST-MID/STLOW are disabled also.

 

Edited by Cyprian

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51 minutes ago, youki said:

What i would love is real monochrome display.   i would love a 1920x1080 in real monochrome. (not shade of grey) ... just as the Atari St or the first Mac were...  Pixel can be White or Black nothing else.

It was so comfortable to work with.   (of course we need application designed for that mode)

You can set some ST emulators like hatari and aranym to use your monitor's native resolution in monochrome.   Any properly-written GEM app should work.

 

I just tried it in hatari.   It slows things down though

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I've used Sebra BITD for my color monitor, mainly for monochrome games and drawing programs that require a more precise resolution than the "stretched out" medium resolution.  And also for using high rez GDOS fonts which also work in low rez by disabling Sebra when rebooting.

 

I couldn't get it to work on ST Emulators but they support real high rez mode on a VGA display so it's a moot point anyway...

 

 

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2 hours ago, Cyprian said:

actually, as my LCD works fine with ST-LOW through VGA, I'm more interested in having a possibility to switch resolution to any available. e.g. from color to mono and and vice versa.

Now in the Desktop preferences, in color mode, ST High is disabled and in Mono mode ST-MID/STLOW are disabled also.

 

Years ago, when I had a multisync monitor that would do the 15kHz that the color resolutions need, I made a cable with a switch box in the middle that would let me use color or mono.  I thought the monitor quit working in the lower sync rate and got rid of it.  I later figured out that one of the wires in the switch box had come loose.  Fixed the wire and it works again.  I've used it with a VGA to HDMI converter that will let me use all three resolutions on an HDMI monitor.

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1 hour ago, MrMaddog said:

I've used Sebra BITD for my color monitor, mainly for monochrome games and drawing programs that require a more precise resolution than the "stretched out" medium resolution.  And also for using high rez GDOS fonts which also work in low rez by disabling Sebra when rebooting.

 

I couldn't get it to work on ST Emulators but they support real high rez mode on a VGA display so it's a moot point anyway...

 

 

Yes, Sebra was what I used back in the day.  I was amazed it could display pseudo-high rez.

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Well, I think that only thing worth to do is involving blitter in conversion of mono screen data for medium res - that's what can improve speed pretty good.

And to go with my second version, what has 2 modes - see first post here.

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Examined that NC Mono - has short and fast code, but there are some flaws too (like not working well at 60 Hz refresh rate), so I did serious changes, starting from installing way:

instead running installer to bootsector (what limits it's size too under 512 bytes) I use AUTO folder run, so simple install, to hard disks too.

Additional 32 KB and code are placed at RAM top instead low RAM, what is more compatible and robust. Works with regular TOS versions 1.00-2.06 . 3 versions done and tested:  CPU only for STs. Blitter version for STs, Mega ST. Blitter version for STE, Mega STE. Blitter gives less slowdown of running SW.

And there are 3 modes: 640x200 px , so 2 adjacent hor. lines are joined. That's not too sharp, so there is mode with all 400 lines, but only half is visible at once, in original sharpness. Mouse vertical pos. will set starting vertical line.  Pic is of course stretched vertically. And there is 3-rd mode, never seen by me, and probably anyone other: quart pic, so 320x200 px at once, to get correct AR. Mouse hor. pos sets horizontal shift.

And with quart mode slowdown of running SW is smallest, because only quart pic. is converted.

 

 

Edited by ParanoidLittleMan
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Yes, pressing Ctrl. and right shift at once will switch to next mode, in circle. That works until SW changes keyboard input from TOS-es to own code. Rare case with SW using GEM (Windows, menus ...) .

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Great!  I think this is now looking like the best monochrome emulator there is.  I'm happy to see you took it out of the bootsector so it doesn't need a floppy to run.

 

Any chance of a 4th mode - 640x400 emulation without scrolling?

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Here is page about with DL: http://atari.8bitchip.info/TOS/ME3modes.html

 

640x400 is emulated in mode 1 - and because in color modes max line count is 200, it works so, that if 2 adjacent pixels, one under other are both black will give 1 black pixel at output.

If both are white, will be white, and if it's like Paul McCartney and Michael Jackson it will give grey pixel at output.

I tried interlaced mode (long time ago), but that's bad and vertical white-black transition flickers a lot.

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On 3/18/2021 at 2:33 PM, kimchipenguin said:

There were more: https://www.atariuptodate.de/en/emulators

(Emulators - Screen, not all are mono/color emulators).

 

I used Emula on my Atari to emulate mono resolution.

I tried mono and color emulators on that site. So, there are color mode emulators for monochrome mode. And 2, what I saw there act pretty similar. Conversion of medium res is OK, and enough fast. Low res converts by both to only half screen, 320x400 px res. After little thinking I see why - converting to 640x400 would be too slow. Too much operations needed, because must put together for every pixel color index value from 4 bit planes, which are in 8 bytes, then get RGB value for it in palette, then calculate brightness from it. 1 src. px goes to 4 dest. px. So, only 5 brightness levels are possible -  0-4 .

I made code for conversion, with speed in first place, and conversion takes almost 2 secs. I don't think that it can be less than 1, even with blitter. So, not good for emulation, maybe only for static screens, pictures.

Example:

MonoGiana.thumb.png.1faab61eea6ce43ca0dacef1742bf6e3.png

 

 

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