NES/SNES 240p dejitter mod

The place for all discussion on gaming hardware
Freedy
Posts: 28
Joined: Wed Jul 31, 2019 8:56 am

Re: NES/SNES 240p dejitter mod

Post by Freedy »

Hello Marqs,
Thank you for the reply!

Unfortunately I have only one display that has composite video input. (Sony Trinitrion)
With an unmodified 3CHIP PAL SNES it works fine. I can try PAL mode with PS2, too, but I think the TV is okay. Just to be 100% sure, I will check it also with a pal ps2.

I've just tried my 1CHIP PAL SNES with borti's earlier superCIC + uIGR board + DFO, without the dejitter feature, and surprisingly there was no color via composite in PAL mode, but I guess that is a completely different issue.

I have a very limited amount of games, I'm not sure if some of these have interlaced mode, but probably no.
PAL Super Mario World, Super Mario All-Stars
NTSC-J - Yoshi's Island, Donkey Kong country 1, Kirby All stars, some game with a cat, and one dragonballZ game, I dont know which one
User avatar
marqs
Posts: 1096
Joined: Sat Dec 15, 2012 12:11 pm
Location: Finland

Re: NES/SNES 240p dejitter mod

Post by marqs »

I can only speculate that the 21.28137MHz and 17.734475MHz clocks generated by DFO are not synchronous (i.e. with exact 6/5 ratio) as in genuine PAL 3-CHIP with S-CLK PLL. None of the listed games use interlace modes as far as I know but it's unlikely to make a difference.
Freedy
Posts: 28
Joined: Wed Jul 31, 2019 8:56 am

Re: NES/SNES 240p dejitter mod

Post by Freedy »

I find this issue strange, if the clock sync would be the problem, I guess others also would have reported this. Or maybe I am the only one who tested composite out on this pcb revision :D I also use rgb in general, just wanted to make sure that everything works as expected.

I created an issue on Borti’s github page, maybe he will have some idea what could have went wrong/how to fix it.

https://github.com/borti4938/SNES_Multi ... /issues/25

I was thinking about reflowing the cdce913, but for ntsc mode clock the same output pin is used on it so I do not know how much sense would it make.
Other idea is to replace the cpld, it is from aliexpress, so who knows what happened to it in the past. Although I kind of doubt it would make any difference. (Cdce913 purchased as new from a reliable source)
Post Reply