The truth about V9948

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Par hit9918

Prophet (2911)

Portrait de hit9918

07-12-2011, 15:54

The 9938 got a great future! Smile Lots hacking still to be done.


SC12 is useless except for photos without much contrast.

Many things ran my head.

flicker on screen 8: use a 2048 colors RRRR,GGGG,BBB model.
If the low bit on RRRR is high, this means the RRR of screen 8 is to be increased every second frame.
Do same on GGG and BB.

Now what if you enable interlace.

Then above "patch for every second frame" is something that happens on every second scanline.
And on a deinterlacing TV, instead of flicker you got vertical hires dithering!?

Further brainstorming: screen 8 scroll was shown.
But Maybe the screen 8 game of the future is the screen 7 game with hires dithering!?
(this time I am about horizontal hires)

Fortunately, emulator tells me sprites are still same fatness and set adjust too is same fatness
(adjust in hires pixels would mean halve max scrollspeed). So no showstoppers this time?

Have many colors by hires dithering. Have hires gfx. Have sprite palette.

Par retrocanada76

Champion (480)

Portrait de retrocanada76

07-12-2011, 17:23

The 9938 got a great future! Smile Lots hacking still to be done.


SC12 is useless except for photos without much contrast.

Many things ran my head.

flicker on screen 8: use a 2048 colors RRRR,GGGG,BBB model.
If the low bit on RRRR is high, this means the RRR of screen 8 is to be increased every second frame.
Do same on GGG and BB.

Now what if you enable interlace.

Then above "patch for every second frame" is something that happens on every second scanline.
And on a deinterlacing TV, instead of flicker you got vertical hires dithering!?

Further brainstorming: screen 8 scroll was shown.
But Maybe the screen 8 game of the future is the screen 7 game with hires dithering!?
(this time I am about horizontal hires)

Fortunately, emulator tells me sprites are still same fatness and set adjust too is same fatness
(adjust in hires pixels would mean halve max scrollspeed). So no showstoppers this time?

Have many colors by hires dithering. Have hires gfx. Have sprite palette.

Are you trying to create the MSX2 version of 109 colors ?

Par hit9918

Prophet (2911)

Portrait de hit9918

07-12-2011, 21:50

Are you trying to create the MSX2 version of 109 colors ?

On the composite port, you get colormix between lines. Is that 109 colors? Does it involve flicker?
Online converter http://msx.jannone.org/conv/ seems to be made for line mixing.

My MSX2 ideas work without this.

The interlace idea is not composite line mix.
Because the next line onscreen is not the next line in time in the signal.
The idea is ordinary mix of things near to each other, and interlace lines are hires.
100Hz devices are supposed to make it without flicker.

The other idea was that the dream of the screen 8 game maybe is better served
by screen 7 with hires dithering + palette abilities for sprites.

Par msxholder

Champion (394)

Portrait de msxholder

09-12-2011, 18:39

Some weird stuff around here
ever seeen an msx vdp ym2220
It's inside the AX 150 !!

Par retrocanada76

Champion (480)

Portrait de retrocanada76

09-12-2011, 20:12

YM is the yamaha code:

V9938 = YM2302
V9958 = YM2703

dunno what could be ym 2220. Which model is that AX 150 ? Msx2 ?

Par PingPong

Prophet (3839)

Portrait de PingPong

09-12-2011, 20:24


As they say here, a lie told 1000 times becomes truth.

interesting concept:
So if i say that you are a very stupid person ( and you are not i'm lying ), then after 1000 times, the people will think that you are stupid?

Par retrocanada76

Champion (480)

Portrait de retrocanada76

09-12-2011, 21:30

doesn't work like that. it must be told in different occasions, by different people and they should not know him personally.

Par Manuel

Ascended (18393)

Portrait de Manuel

09-12-2011, 22:49

Hey, how did you know these Yamaha codes? Is there a list?

Par sd_snatcher

Prophet (3498)

Portrait de sd_snatcher

10-12-2011, 03:00

The V99x8 code was an ASCII-only reference code. Back in the days Yamaha didn't sold those chips by these codes. To order from yamaha you had to put your order using Yamaha's own part#.

This code is written on the bottom-left part of the VDP.

V9938: YM2302, YM2302B and YM2302C
V9958: YM2703

Curiously enough, even having the ASCII logo, the V9990 don't show it's YM-code on its top.

Par Manuel

Ascended (18393)

Portrait de Manuel

10-12-2011, 13:00

What's the difference between the YM2302, YM2302B and YM2302C?

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