N64 Internal RGB amp mod help.

I know, I'm amazed it actually works. The Cyclone II I'm using doesn't have true TMDS voltage level outputs AFAIK, so I'm using LVDS voltage levels (with the HDMI / DVI TMDS protocol).
It seems to be working fine on my monitor with a 2 meter HDMI cable.

It should work OK at lower resolutions, but maybe not for upscaling higher than 720p etc. (not that I'd know how to do that anyway).

Currently, it's outputting a test pattern at the bog standard 640x480 @ 60Hz.
I need to work out how the sync works for interlaced sources (like the N64), it will then at least work on most HDTV's etc.

A scan doubler might be tricky - to convert interlaced to progressive usually means storing the first "field" into memory.
(I'll have to ask Marshall how he did his simple doubler for his VGA adapter)...
http://forums.benheck.com/viewtopic.php?f=58&t=43034

The great thing is, when this is all working, we won't need any extra DAC chips at all, it's just an HDMI socket soldered to eight pins on the FPGA and that's it! :cocksure::love_heart:

It should be possible to use this on other consoles, but it depends if they allow access to digital video signals.
I believe the original NES / Famicom outputs composite directly from the PPU, so HDMI won't be possible unless the FPGA is used to replace the entire PPU as well.

I know people would love the idea on the NES, but it really is overkill IMHO. HDMI is probably best used on 16-bit / 90's era machines.

More news soon. I'll make a new thread if / when I get the N64 working.
OzOnE.

 

i am pretty sure gamecube can be done too but i do not know about the others. as you said, the console has to have a kind of digital output at first for native HDMi. some kind of ADC solution like the wii has currently have doesn't interest me.

about the topic, Bad_Ad84 kindly rgb modded a french N64 for me. it uses c-sync as sync signal taken from pin 18 of S-RGB chip. it works perfectly fine with my samsung led tv and gives a great picture.

as everybody might have guessed, this kills the composite output of the console. you get black screen when you use official composite cable. not a problem for me though.

 

Yep, they should really have thought about standardizing cables a bit more. For the RGB SNES / N64 cable, they should have just used the different pin for C-Sync.

Or, do it properly and put a switch in the RGB cable which not only switches the +5V to pin 16, but also switches the Comp Vid input between comp vid and C-Sync.

Quick update: HDMI test pattern from FPGA now working fine on my 47" Samsung LCD!
(The Samsung also needed +5V on HDMI pin 18 before it would even look for a signal.)

 

just checked the other thread. When I used c-sync with or without a 75 ohm resistor in series, the image was clear (no x hatching) but it was too dark with an official gamecube cable:

this is probably down to the cable used. I didn't have an official pal snes cable to test.

A few people were wondering how on earth this impacted the brightness but what you say on this point is most likely true Ozone - samsung do something funky..

Looking forward to the HDMI

 

Nintendo do something funky:
http://members.optusnet.com.au/eviltim/gamescart/gamescart.htm

GameCube SCART cables and SNES SCART cables are wired differently.

 

Geez, what a mess!

That's another reason why it's maybe important to use a resistor when doing the C-Sync mod? On the SNES and Gamecube, it has +12V on pin 3!

I'm sure there was a mention of +12V on pin on PAL N64's too? But, my PAL N64 is "NUS-CPU (P)-01" and it has the same layout as the REV04 NTSC (ie. Q1 missing, so no output at all from pin 3.)

Crazy stuff. :mad-new:

EDIT: Oh btw, they use +12V to pin 8 on the SCART plug so the TV will auto switch to the SCART input and 4:3 mode (instead of 16:9 mode).

 

OzOne what is this HDMI project, is this the same as the VGA module pcb i saw awhile back (adding a VGA port to the N64)???

 

No, you're probably thinking of Marshall's VGA board project which I linked in post #41.

I did a similar thing ages ago, but I generated the RGB signals directly from the FPGA pins (no scan doubler, just direct to RGB SCART).

This HDMI design should work fine on a similar board to Marshall's, it just needs an HDMI socket instead of VGA.

He also added some scan doubler code to convert the N64 (interlaced) to VGA (progressive).
This can be done by simply repeating each line, but this won't necessarily give the best image (depending on the N64 game's output resolution)...

So, he added the SDRAM so he can do more advanced scan doubling / scaling.
I'm not sure how far he got with it, but knowing Marshall it's probably running just fine. :encouragement:

What I'm hoping to do at first is to output standard 480i or 240p directly via HDMI. I'll then try to do some doubling / scaling stuff.
Right now I'm in the process of stripping some wires and hooking up the N64. :friendly_wink:

Another thing I just realized is that we could do something I've wanted to try for years...
Add multiple HDMI outputs, so you can play multiplayer (ie. splitscreen) games on many separate TV's!
So, like in Mario Kart or Goldeneye with four players, but each TV "zooms" into the relevant section of the original image.

I'm still stunned that it's so easy to generate DVI / HDMI from a few pins. I knew it was out there somewhere.
Even on this cheap FPGA, there are enough spare LVDS output pins that you could technically add around TEN HDMI outputs!! (not sure what you'd do with them though).

OzOnE.

 

yup pal TVs use this 12V to switch to scart.

i have 2 pal snes rgb scart cables i use them both on my PAL SNES and PAL N64.

for PAL SNES as the 3rd pin multi av is 12V (that is valid for only PAL SNESes, NTSC SNESes have c-sync there) and official cable connects this to pin 8 on scart, my TV switches automatically to the scart channel when i turn the power on and it is in 4:3 mode. as soon as i close the SNES, it goes back to the channel it was on.

for PAL N64 with RGB mod with the same cable, this doesn't happen as pin 3 for multi av isn't connected to 12v. and TV switched to the 16:9 mode for the first time, but after i saved the channel settings as 4:3, it switched to 4:3 just fine.


none of the N64s (PAL or NTSC) has pin 3 connected to 12 originally. though it is possible to put 12v on pin 3 of N64 multi av, find a cable which has pin 3 connected (like official snes pal rgb scart cable) and just get the same functionality as PAL SNES. auto switching and 4:3 mode.

though auto switching is not a big deal in my opinion neither the 4:3 thing.

about the N64 hdmi thingy, can you shoot a video? i am really very interested in this mode since the first time i learnt that N64 has digital output. i thought it was such a waste to connect a DAC to it to create RGB video.

 

I am on the same boat as you. I followed the same guide. I have a NUS-CPU-04 board. I am using a sync on comp SCART cable going to an HDMI upscaler/converter but I get no picture or sound at all! Any help would be great.

 

i'm not quite sure what you mean with "comp SCART cable"

for RGB you need ->

color signal
R NintendoAV 1 (after mod) SCART 15
G NintendoAV 2 (after mod) SCART 7
B NintendoAV 4 (after mod) SCART 11

Audio
L NintendoAV 11 SCART 2
R NintendoAV 12 SCART 6

As Sync you can use either the FBAS signal or Cysnc (better use this)
Csync NintendoAV (not default on N64) SCART 20
FBAS NintendoAV 9 SCART 20

RGB enable signal
SCART 16 1-3V (5V should work, too)

Ground (it's internal conncted, so you don't have to connect every pin)
NintendoAV 5,6
SCART 4,5,9,13,18,17

here is a good site on how the nintendo multiav is populated on PAL/NTSC and different systems
http://gamesx.com/wiki/doku.php?id=av:nintendomultiav

Here is your scart pinout
https://en.wikipedia.org/wiki/SCART