I need help from a VIC20-ntsc owner

[aitsch]

hi,

i am comming from germany, near Hannover and i am new on this board.
I was born in 1973 and in 1984 i got my first homecomputer -> A VC-20 (german notation).
Since approx. one year i start to learn 6502-assembly.
Now i nearly finished my first VIC-20 game.

[youtube]https://www.youtube.com/watch?v=LfeP7CxvGXM[/youtube]

But i run into an issue. The game should works for pal and ntsc machines.
I only have a pal maschine here and need to test all ntsc stuff in Vice.
The monitor is stretched to the maximum 25 columns and 29 rows (reg. $9000-$9003).
I got 2 different results for the screen adjustment in two Vice versions.

If i set the value of $9000 to 1 i got a gap in Vice 2.4 but in Vice 3.3 it fits.
If i set the value of $9000 to 2 i got a gap in Vice 3.3 but in Vice 2.4 it fits.

Can anyone with an original ntsc-hardware start my attached programm and give me feedback which value fits an a real hardware.
The only thing to do is press a key an look which value is the best.

Thank you and cheers

aitsch

[Mike]

Nice project!

Your own ship reminds me of one of the enemies in Anarchy on the C64 (those tanks that could only be thrown back by shots, but not stunned).

I don't have an active NTSC VIC-20 handy at the moment, but I can tell you that some versions of VICE around 2.4 suffered from a regression bug in the X screen position register: for some obscure reason, one of the maintainers decided, that the standard display window within the cyan border "ought to be centered" on screen, which in fact it isn't on real VIC-20s. Actually, it is shifted roughly half a column to the right, on most NTSC displays, which is also correctly rendered (again) this way on newer versions of VICE.

That being said, POKE 36864,1 and POKE 36866,25 (or POKE36866,128+25 if you position the screen base at an 1/2 K) will give you centered 25 columns. Note however, the most-left and most-right column both very likely show cropped on CRT monitors. Unlike PAL, the actual amount of border is rather small on NTSC.

[chysn]

I'm using an NTSC CR VIC-20, and I'd be happy to help. But I'm not sure what to do with your program.

LOAD "NTSCTEST.7Z",8

RUN

?SYNTAX ERROR IN 20033

[aitsch]

Thanks for your answer,

the programm is packed with 7-zip compressor.
Otherwise it was not possible to attach it here.
Please unpack it first.

https://www.7-zip.org/download.html

[chysn]

Thanks for your answer,

the programm is packed with 7-zip compressor.
Otherwise it was not possible to attach it here.
Please unpack it first.

https://www.7-zip.org/download.html

I'm seeing only downloads for Windows. Sorry I couldn't help.

[chysn]

Wait! Got it. It looks the most centered when $9000 is 2

[chysn]

[Mike]

Chysn, what you don't see on your monitor is, that the rightmost column is actually clipped off by half in the video signal, and there really is a half-character wide cyan border stripe in the far left. Current VICE versions show very accurately, what part of the video signal is sent to the monitor. Everything around that is sent as 'black torch' and won't ever show up.

Anyhow, the display confirms what I wrote in my earlier post: regardless whether 1 or 2 is used in the X position register, with 25 columns the right- and leftmost columns won't show completely on most NTSC CRTs. Ghislain's newest installation of Realms of Quest for that reason only uses 23 columns, and even there it's a close call on many NTSC displays.

[aitsch]

Thank you for testing.

Oo .... that looks bad.
you cannot see the boxes in the bottom of the screen

it looks like 29 rows are to much for ntsc.

can you adjust or compress the picture of monitor manually?

[Mike]

In a similar vain, darkatx and I once established a 23x26 screen mode on his NTSC display. Even that one was off a few pixels (slightly vertically shifted up) on another NTSC user's monitor later on. Of course, the corners are the most critical part with the rounded edges of CRT monitors.

Besides, not all TV sets or monitors have knobs to adjust screen size and position ...

(Sorry for the blurred photob*cket pictures. The posts were written at a time where the forum didn't support attachments, especially for pictures. But you should see I tried my best to get everything displayed on NTSC.)

P.S. Willkommen bei Denial! Hast endlich vom Forum-64 hierhin gefunden ...

[aitsch]

That thwarts my plan.

The game is nearly finished and i cannot change the resolution
All maps wouldn't work with less columns.

I have to sleep on it for a night.

@Mike: Danke für die Begrüßung . Ich habe schon viele tolle Beiträge von Dir hier gelesen.

[groepaz]

MMmhh somehow i have a dejavu, didnt we had a thread here a while ago where we worked out the correct offsets (which i then put into VICE)? *shrug*

[Mike]

@chysn: PM sent.

[chysn]

you cannot see the boxes in the bottom of the screen

can you adjust or compress the picture of monitor manually?

The 1702 does not have compression controls, at least using the external knobs. I have:

* Horizontal Position. I can use this to slightly adjust the screen from side to side. I can center the screen to see most of the top boxes, but it still seems like something is missing, based on your original images.

* Vertical Hold. I can use this to see that there are boxes on the bottom. However, I can't see the bottom boxes without the screen becoming unsynced and actively scrolling around. I can slow it the scrolling down, but it always scrolls. Once I get it nicely locked in place, the bottom boxes are always off the edge.

I wish I could tell you if S-Video or a modern monitor is different. My VIC-20 system is stuck in 1983, video-wise. Tonight, I'll hook up to the living room TV and let you know if I see more.

[aitsch]

Thanks chysn for your effort.

For the moment I can't evaluate if it make sense to publish the current version of my game for NTSC machines.

If i send 2 copies to you (one with value 1 in $9000 and the other with 2) would you do me the flavor and test it on your vic?

Maybe you can post some pictures and your appreciation if the game is acceptable with this resolution.

aitsch