rgb to component

[phreak97]

i'd really like to have an rgb to component box, but they cost waaay too much for me right now, is there any ic which will do it for me? like the way the cxa chips do it for rgb to composite/svideo?
thanks

[Aidan]

It's basically some matrix maths. It can be implemented with a bunch of opamps, if you don't mind doing some work. If you're looking for a single chip solution, I've not come across one (yet).

Edit: Take a look at http://www.siliconchip.com.au/cms/A_102648/article.html

[Segasonicfan]

I've been looking into this for a while.  I cam across that site too, but paying $6+ for the instructions is just rediculous.  epanorma has some very nice info  on the subject, but thes best stuff I've found is here:
http://elm-chan.org/he_v_e.html
Like Aidan mentioned, it takes some opamp work.  I've found it to be very annoying stuff but I did finish a test circuit.  Thing is, it set me back $30 for parts plus hours of time.  and I still gotta make the +-5v power supply...

-Segasonicfan

[D-Lite]

You can find an RGB->Component (and S-Video and composite) encoder at www.neobitz.com

I know that www.crazearcade.com will be selling a component only encoder within the next few months for around $50-60.

[Darklegion]

National do a single-chip solution and they offer free samples (although no longer free delivery).Search their site for the chip, I can't remember the part number right now.

[phreak97]

i cant find it on national.com

[Darklegion]

http://www.national.com/pf/LM/LMH1251.html

[phreak97]

that seems to be a component to rgb converter, i need an rgb to component converter.. or does it do both? it didnt look like it does from what i read

[viletim!]

Maxim (maybe AD and nat too) sell 3x 'video' opamps in a single package. There you go...single chip RGB to YUV converter.

[darkegion]

Sorry mate, its easy to get those 2 confused

[RARusk]

After looking over the datasheet for the LMH1251 I definitely need to get me one of those. It will be perfect for PlayStation 2 and Xbox usage. The only question is where to find an adapter board for a surface mount 24-pin chip so I can use it without having to solder thin wires to the bottom of the pins similar to what I did with my EL1883 chip.

[Segasonicfan]

Wow, what a great little chip.  I can't believe I haven't seen it before.  My only question is concerning the Sync operation.  Does it convert TV standard 15khz Component to 30khz VGA output?  That would make it an upscan converter as well...

If not, then would it simply leave sync rates alone and work for non-VGA applications (like the PSOne screen?)

Anybody know?

Also, thanks for the link D-Lite...I'll definitely have to look into that...

[RARusk]

The chip doesn't upscan. But it is compatible with the 480i scan rate. Better still it is MacroVision compatible which makes it useful for DVD players too. I really got to go after that chip.....

[Segasonicfan]

I already ordered 2 of them for National's website.  The reason why I didn't hear of this chip before is because it was JUST released this October!  Talk about new technology  Yeah, the Macrovision stuff is amazing...I figured the upscan conversion was asking a little much though.  I really want to play some Genesis on my new 17" VGA screen though...:/ There are some reasonable upscan converters on Ebay for this (GE makes them as do other companies), but the don't support RGB inputs...only S-Video, component, and composite.  Maybe I can hack one open and find an RGB input? mayyybe....


For now I'm going to test out this new chip for my RGB-Component Converter so I can play CDX on my HDTV  Oh, and if anyone wants the article that's $6 to buy online let me know, I have a copy of it (tells you how to build RGB and Component converters).  

-Segasonicfan

[RARusk]

Yeah, I'm interested in a copy of that article. I'm curious on how they did that.

I also went looking for a chip that would take digital component video, like the signals that are on the Xbox motherboard, and convert it to RGB Analog. I didn't find it but I was taken to Intersil's web site which I hadn't been to in quite some time.

I am currently using their EL1883 sync separation chip in my RGB box and I decided to see if they came up with something better. They did. They have a new chip out called the ISL59885. It is exactly like the EL1883 but it can autosync to any scan rate you throw at it. No more RSET resistors. But you still need to attach a capacitor to a pin called CSET to get it to work properly (I think it uses a 56nf cap to ground). And all in a eight pin package (surface mount unfortunately). I plan to write Intersil next week to see about getting some samples.

[Drewman21]

Hey Segasonicfan,
  If you come up with a how to wire up that chip for component please post it up.  I would love to go crazy with it in some of my old systems.  I know they were samples but how much did it set you back on shipping? And how many did you end up getting for samples or did you ask for a certain number.  Thanks for doing the foot work on this!

Drewman

[Darklegion]

Yeah, I'm interested in a copy of that article. I'm curious on how they did that.

I also went looking for a chip that would take digital component video, like the signals that are on the Xbox motherboard, and convert it to RGB Analog. I didn't find it but I was taken to Intersil's web site which I hadn't been to in quite some time.

I am currently using their EL1883 sync separation chip in my RGB box and I decided to see if they came up with something better. They did. They have a new chip out called the ISL59885. It is exactly like the EL1883 but it can autosync to any scan rate you throw at it. No more RSET resistors. But you still need to attach a capacitor to a pin called CSET to get it to work properly (I think it uses a 56nf cap to ground). And all in a eight pin package (surface mount unfortunately). I plan to write Intersil next week to see about getting some samples.

RARusk - if you didn't want Macrovision I would say just use the LM1881.Despite it being an old chip it has always had this function I believe.No need for playing with RSET either, it should just work with the standard value.I know it works too because I have seen 480p, 720p and 1080i working through the chip and so have many others.
Also a member on xbox-scene(ferrari_rulz or something) has used the IS9885 chip, which was hoped to be able to fix the purple screen with 720p and 1080i on xbox by converting tri-level sync to bi-level sync.It didn't fix that issue and Intersil seem to say that that particular problem is not caused by tri-level sync so maybe the the issue is at the bios level.Anyway for your purposes the autosync function does work, so its probably still worth your while in the case of the PS2 and its macrovision

[Guest]

Here's the article (all the information from it anyway):
http://files.filefront.com/rgb_converter_i...;/fileinfo.html

Their server went glichy for a bit and I wwas able to snag it for free  Basically the same as other ones on the net though. uses op amps and an LM1881 for Sync.  

I ordered 2 samples from National and they charged $9 something for shipping.  Kinda steep but eh...I can't get them anywhere else for less.  

-Segasonicfan

[RARusk]

The EL1883 is the first sync chip to offer MacroVision compatibility. The LM1881 is an old chip that doesn't have that feature. Run a MacroVision encoded signal through it and your screen will get messed up.

True, the 681K Ohm RSET resistor will work but your screen will shift when you go from one scan rate to another. Most people, including myself, don't like that so it is best to use a chip with an autosync feature like the ISL59885 or the EL4511. There is also a circuit, posted at Intersil, that you can build to make any sync chip, including the LM1881, into a true autosync chip.

As for the purple screen, I don't know what to do about that but if I can find the right Digital Component Video to RGB Analog conversion chip I might be able to make that problem irrelevant.....

[Adeptus]

Aren't there Component output cables for XBox/PSX/GC?
Don't they convert from the RGB output by the console?
Wouldn't it be a simple(?) matter of rewiring the plug to a more universal connector?

[NFG]

The Xbox outputs component natively.  The PS1 doesn't at all, but the PS2 does.  The GC outputs digital component, and uses a custom chip in the Nintendo component cable to convert it to analogue component (or, with a mod, RGB/VGA).

[RARusk]

The signals on the Xbox motherboard are PC Video signals. Thay can be either Digital RGB or Digital Component Video depending on what plug you have in the A/V port. These signals are always progressive scan even for things that are not supported. These signals go to a PC Video to TV chip. On my unit it is the Focus chip. On earlier models it is the Conexant. On the newer models it is something else.

Knowing that these raw signals are progressive scan I thought of two questions:

1. Why is it that not ALL the games are Progressive Scan supported (at least 480p)?

2. Why is it that DVD playback is not Progressive Scan supported? It couldn't have been that hard.

The thing here is to find a chip that can convert the Digital Component Video to RGB Analog. I am focusing on the Component Video since I can take advantage of the 720p signal for the games that support it (when in Component Video there is a submenu that is activated that will allow you to determine resolution settings). I was pointed to the chip that is inside the Component Video cable for the Gamecube. But specific information on the chip and the Gamecube's Digital A/V port is almost nonexistant. I would almost have to break into Nintendo to get any kind of info. So I am looking for alternatives.

But if I can't find the right Digital Component Video to RGB chip then I will try to find a Digital RGB to Analog RGB chip. I won't be able to use 720p (since the submenu won't activate in RGB mode) but I will be happy with at least 480p.

The beauty of the hack, with the right chip, is that you don't have to modchip the unit or mess with the BIOS. Tap into the digital signals off of the motherboard and away you go. The Xbox will do its merry thing and I get what I want. Genius.

Yes I could go and convert 480p Analog Component Video to 480p RGB Analog but I don't want 98% Progressive Scan support, I want 100% Progressive Scan support and then some.

[Guest]

got the chips in the mail but HOLY CRAP are they small...I didn't realize they were smaller than SOIC :/  I can't even solder 30AWG wire to the pins there so tiny and close together...anyone have any suggestions?

-Segasonicfan

[RARusk]

Well, that's not good. Best thing to do is find a adapter board of some kind and solder paste. Carefully put the paste on the board contacts and place the chip on the board then place the board in a hot skillet, like the ones you cook food with, to get the solder paste to melt. Although I don't know how well that would work on such small contacts.

By the way, I am currently waiting for samples of the ISL59885 sync chip to come in from Intersil. I need to get additional parts tomorrow.

[Guest]

Good news.  I went through my old broken PCBs and found a chip with the same pin spacing as the LMH1251.  I cut apart the PCB and combined to sides for a full set of solder terminals!  Now I can start adding the external components but I have one question...what about the logic stuff?  The datasheet talks about pins 23 and 22 being set to high and low logic levels (to choose the output).  I think this would require programming which I definitely want to avoid (since I have no knowledge of programming whatsoever).  Any ideas as to what I should do about these pins?  Also, it looks like I'm going to have to pick up another circuit as seen in figure 2 of the applications to amp the RGB and it looks like it also needs some opamps for the H and V sync...

If anyone can help me out on this I'd really appreciate it  Obviously I'd like to avoide the opamp stuff as well and just see if an image is displayed first.  What would be best is if someone here who really knows their stuff could give me a schematic of how I should wire everything.  That would be awesome.  

-Segasonicfan

[NFG]

'high' is Vcc (usually +5v) and 'low' is GND.

[Segasonicfan]

yea, that's what I thought.  But every time I read the word logic in a datasheet I freak  Good to know that for sure now, thanks

-Segasonicfan

[Segasonicfan]

Just wanted to give an update for everyone-

Received 3 more samples in the mail and i got one completely applied to a PCB board (the hardest part being a TSSOP package) and I'm wiring it now (which shouldn't be much of a problem at all).  I'm going to be using this on my PSOne LCD screen so I was wondering what setup should I use?  fig 1 or fig 2?  Figure 2 doesn't tell me what the diodes are which makes that a little hard to do :/  I figured I'd build the test circuit and wire it up to the inputs on the PSOne screen since it has an RGB opamp.  

Also, I need to combine the sync lines to use on the PSOne LCD, so I figured I'd use this: http://www.tkk.fi/Misc/Electronics/circuits/syncbox.gif

Sound good?  Any advice is much appreciated.  Thanks.

-Segasonicfan

[Segasonicfan]

OK I hooked up everything like the test circuit (used LM1881 to strip C Sync from composite) and I got an image, although not a very good one.  I could make out stuff but the colors were moving/bleeding and it was very dark... :/ Is this maybe because I haven't configured it like in figure 2?  I wish I coul get some help on this....

-Segasonicfan

[RARusk]

You don't need the LM1881 chip for sync. The LMH1251 will separate sync for you. There is a pin that you attach the Luminance to so you can get sync from the 1251. Just combine the two signals together to get Composite Sync.

The datasheet did specifically state that you need an amplifier in conjunction with this chip as well as a logic inverter for the sync lines. I don't know if the chip that is used for the DreamCast VGA boxes, for the sync lines, will work in this case.

[Segasonicfan]

RARusk thanks fo much for the reply.
I know teh LMH1252 produces sync but it's split which makes it no use to me until I get the chip for this: http://www.tkk.fi/Misc/Electronics/circuits/syncbox.gif
I was just using the LM1881 for testing purposes since the PSOne LCD requires C Sync input.  From what I've read you can't just solder H and V sync together to get V sync, you have to build a circuit for it like the one above.  I don't know too much about this though.

I think an LM1881 will work well for testing purposes though since I'm just trying to get the RGB lines working.  I'm ordering that tripple amp buffer National recommends and hipefully that will fix the problem, but I still need to know what the diodes are.

as for the logic inverter...geeze I don't even know what that is I thought it only needed inverting opamps.  any specific chip numbers that you could recommend?  I just need a schematic and I can go ahead and build that too...

*whew* this is turning out to be a lot more work than I thought

-Segasonicfan

[RARusk]

There is a much simpler way to combine Horizontal Sync and Vertical Sync to get Composite Sync. Run the Horizontal Sync through a common 1N4148 diode and run the Vertical Sync through an 820 ohm resistor. After the sync lines are run through these components THEN combine them together. Works very well.

Don't know anything about logic inverters. That is why I suggested looking at the chip that the DreamCast VGA boxes use for their sync lines.

When I get my hands on the LMH1251 I will use the CXA1145 chip for amplification (after I remove it from another Sega Genesis unit).

[NFG]

Many chips can be used as inverters.  The 7404 is the first choice for many, but I use a 74157 (from a genesis pad) as a multi invertor for the switchless saturn mod.