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  • Joined: 09 Apr 2005
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Post Posted: Sat Apr 09, 2005 8:45 am
I've always wanted to play all my GG games on my TV, but I'd always hoped that it would be done through the Sega equivalent of the Super Gameboy cart for the SNES. Might it be possible to make a cart like that out of this board?

Anyhow, I want one of these for sure. But if there's no case, how will we play it? I don't wanna perform any surgery on my current GG, so would I have to buy another GG to operate on? How much more would one with a case be?
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Post Posted: Sat Apr 09, 2005 1:49 pm
A Super Game Boy cartridge is essentially a screenless gameboy, outputting graphics to the SNES its connected to. I would assume the SNES then keys in the GB graphics in its video output.

The Sega Mega Drive is backwards compatible with the SMS. The GG hardware is the same as the SMS with a few changes, mainly an extended palette and different interaction from the start button. Sega did announce a "Mega Gear", letting you play GG games on the Mega Drive, but it was never released.

I see two solutions to the palette problem, first one would be to have the Mega Drive run a GG game in SMS mode, and output its video to the cartridge with its own video hardware, which blanks the borders of the picture, and sets correct palette values. In fact, some specially programmed games might signal the "Mega Gear" to skip blanking, extending the view from GG.

Another one would be altering the palette values of the GG game to the closest SMS value (would it be possible to use the Mega Drive palette in SMS mode?). This wouldn't look as good (think Tec Toys Sonic Blast port), and it would leave additional visual data (in some games garbled graphics) on the sides.
 
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some mod
Post Posted: Mon Apr 11, 2005 5:08 pm
Quote
Can't wait to hear the results. :-)


Hello, I actually work on limit the pcb size, I hope completing this this week...

Quote
so would I have to buy another GG to operate on? How much more would one with a case be?


As soon as I complete the pcb, I'll seach a correct and inexpensive case.
Remember you need some solder inside the GG to connect the board wich is external, there is NO simple way to put the pcb inside the GG ( any Surface Mounted Component specialist here? ).

Quote
Might it be possible to make a cart like that out of this board?


Appart the solution proposed by Phredreeke, we can imagine an hardware way ( beware it's really theoric).

-1- find the complete pinout of the GG asics (all version).
-2- desolder properly the asic from a GG.
-3- desolder the video and audio processor of an SMS
-4- find a way to properly reconnect the GG asic on the SMS board 8-(
-5- use the TV Gear to output the video signal

This way we obtain a SMS with built in GG feature...
It's theoricaly possible but a nigthmare to do...

...In other hand we can reverse the problem and create a fun mod:

-1- take the pcb from an old GG with damaged screen
-2- take the case of a SMS with non working board
-3- take an aspirin tube..., mix both element and add the TV gear, an SMS cartridge connector, a switch to select between it and the GG one, an joypad connector ( however no way to install a second joypad)...

Voila! An SMS with built in GG compatibility :-)

This way is IMHO far more simple than my first solution, but'll always require lot of work ;-)

Xavier
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Post Posted: Mon Apr 11, 2005 5:43 pm
Maybe Tomy at Tototek could make these for you. You'd reach quite a wide audience this way! It'd probably be a much more effortless way to make some cash too.

-Rob
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asdf
Post Posted: Tue Apr 12, 2005 1:10 am
A very thin PCB with SMD components and 1 single TQFP CPLD would fit.
 
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Re: new TV Gear schematic
Post Posted: Mon Apr 25, 2005 6:56 am
xavier wrote

IMPORTANT: This schematic is for the 2 ASICS Version!
Sorry, I don't own a single ASIC GG so I can't identify the pin 10/30 substitute


Can somebody identify what pins on the 1 ASIC GG correspond to pins 10/30?

An update: I have constructed the TVGear circuit, but of course my main problems are finding the r/g/b validation pins on my 1 ASIC GG. It's very difficult, as I have to find 2 different pins at the same time. Xavier, can you give me any advice on how to go about finding them?

So, my TVGear is all connected, and the circuit is complete, except for the variable resistor in the R validation. I don't have a variable resistor yet, so I just put in a 1kohm resistor for now. So, with this, as I poke around the GG PCB, I found some interesting pads, such as C5 and T1, which give a picture, but not the proper logic for both R and G/B. There are many vertical lines in the display, and even some video noise... so these are probably the system clock, right?

Xavier, without knowing the proper pins to use, how can I adjust the variable resistor on the R validation line? With just a 1kohm resistor in its place, would that be good enough to separate red, green, and blue?

So, please help! On your 2 ASIC GG, where are pins 10/30 located/near? Do they go to any test pads, or feed into resistors/capacitors/etc? Maybe that's one way I can locate them.

Thanks.
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Post Posted: Sat Apr 30, 2005 6:13 pm
er, I've updated my last post. Cheers.
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Post Posted: Sun May 01, 2005 4:04 pm
Sorry Chris, I'm just back from vacation ( ONE WEEK in no man's land: no internet, no portable phone, no cinema....)

First you can try to replace the variable resistor by a 110ohms fixed one.
After some test it seem to give good result with most of the ICs.
But keep in mind even with an incorrect value you must obtain a stable image,
simply light blue look purple.

I think I must clarify some detail: during TVGear conception, the 3 valid signal was the main problem, in theory using a decade counter driven by the pixel clock and connected to the 3 latches was the correct solution...
... in pratic, it simply never work!

In despair I eventually found a pin wich could directly drive the blue and green latches ( pin 30) 1=green valid, 0=blue valid.

But the red was more tricky, for simplicity sake I take a signal pin10 ( I suppose it's the pixel clock or very similar) and horribly tweak it, in fact all electronic students must pass the next lines or forget it because their teachers'll kill them ( and after me):

!!!The filter and the associate Schmit triggers act as a clock divider/delay line!!!
It work perfectly, but it's IN NO WAY something you must use for your study, not a single teacher'll accept it, to put it simply it's a HACK.

So maybe there is no equivalent pins for the 1ASIC version, or maybe the first solution (the decade counter) work on it...
I'll try to find a way.

First try to connect T13 on pin10 input, then with a very thin wire try to test all the pin of the ASIC for pin30 equivalent. BEWARE do not short-cut some pin.
I highly suspect T13 and pin10 to be the same thing.

Good luck and be patient, of you don't find like this, we'll try something else.

Xavier
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Post Posted: Sun May 01, 2005 10:25 pm
Welcome back. Thanks for replying.

Sorry for not understanding so much about the logic of the NAND gates and such. But anyway, I decided to eliminate them, and just poke around with a wire connected to the CLOCK pin of one of the latches (d2a convertor). The pad (T13), which is directly to the right of the large FB1 pads (check here for the scan http://www.smspower.org/dev/ggtv/), doesn't seem to give any good signal. Sorry, I don't know much about what kind of signal I am looking for, but it should be a ~15mhz or 5mhz signal, right? Well, T13 gives just a solid band of colour at the top of the screen. I don't think it's what we're looking for.

FB1 gives a good picture (but with many vertical lines in it). The image has equal brightness for all R,G,B pixels, so I think it's triggering for each R,G,B clock. That means it's 15mhz, right?

Another good signal seems to be the pad at C5, directly right of the T1 pad. Again, it has many lines in it, but it seems to be triggering when G and B are active. There is no "Red" in the picture.

The only other lines that I could find are on the right side of the ASIC. Two of those pins give a very solid "Valid Red" and "Valid Green" signal, but the horizontal resolution seems to be 1/2 or 1/3 of the real GG picture. I think they are also present on the chip (RAM) to the lower-right of the ASIC. I dunno if they can be useable.

So, can these pins be of any use? Do they sound similar to what you have found in your GG, or are they a totally different type of signal?

Thanks for any help.
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Post Posted: Tue May 03, 2005 9:03 pm
Quote
Two of those pins give a very solid "Valid Red" and "Valid Green" signal, but the horizontal resolution seems to be 1/2 or 1/3 of the real GG picture. I think they are also present on the chip (RAM) to the lower-right of the ASIC. I dunno if they can be useable.


Sorry Chris, this pins are not usable, they are used to access the video ram and are too slow.

FB1 seem really promising. I'll not be accessible until next monday, I have a new idea for the 1 ASIC and I hope I can give you a new solution next week, until then try to found a 74HC4017 or 74HCT4017 NOT AN OLD CMOS VERSION LIKE CD4017 with chance it'll be enough and replace the actual NAND control logic once we found the correct clock signal.
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Post Posted: Thu May 05, 2005 3:23 am
Hi, I managed to get a 2 ASIC Game Gear (I got 5 junk GGs through Yahoo Japan), and so I connected the wires on this GG. Pin 30 indeed seems to be blue_valid, but it appears to be 1=blue 0=not blue. I connected pin 30 directly to the clock pin on the DAC circuit and there was brightness only in areas of blue.

Pin 10 looks like a valid signal, but it looks like "yellow_valid"! It is active in any areas of red or green, but pure red or green are a little dark... Areas with yellow are full brightness! (A little strange).

So, anyway, after hooking up all the pins, the colours seemed wrong. I have a variable resistor now, so I tweaked it. Red looked good indeed, but green and blue seemed mixed together. If blue_valid indeed is valid when high, then these colours may need to be swapped. So anyway, I swapped the connections for pins 10 and 30 on my PCB, and swapped blue_valid and green_valid, and the colours were fully decoded! However, the hues were all wrong, and the triggering of red was happening 1/3 a pixel too late. Plus, there was noise in some areas of colour (mostly in the blues...)

So, I don't know how to fix this up. Xavier, whenever you become available again, could you please again check the logic of the NAND gates in your diagram? Is pin 30 valid for blue when low or high? And, what's the behaviour of pin 10? (Active on yellow?!?)

So, thanks for the help.
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Japanese article
Post Posted: Sun May 08, 2005 4:40 pm
Not going to try reading it all or translating from Japanese, but Sankichi has been up at mod a Game Gear for AV output and added a joypad port as well.

Picture of the result:
http://www.sankichi.flnet.org/image/ggtv-all.jpg

Very interesting mod, since in the end you have a home-console-like thing. Note how he plugged a Famicom pad, probably to have the Start button on the pad. A Megadrive or hacked SMS-pad could fit as well.

See his site:
http://www.sankichi.flnet.org/
http://www.sankichi.flnet.org/gg-hist.html (Game Gear part)
He mention Game Gear hardware variations here.
ggtv-all.jpg (50.31 KB)
ggtv-all.jpg

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Post Posted: Mon May 09, 2005 2:41 am
I'm amazed that he managed (?) to fit all the decoding circuitry into the GG unit. I wonder how he did it...
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Post Posted: Mon May 09, 2005 3:03 pm
Looks like he saw this thread and went to town...

Can anybody translate that? I'd like to know whtat he says about the 3 different versions of GG and how to distinguish them.

-Rob
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Post Posted: Mon May 09, 2005 3:33 pm
Well, the gist of it is:

He guesses for now that only the 2 ASIC GG can have the RGB output applied to it (as it is currently designed.) There have been several revisions of the GG hardware: Black GG -> Colour GGs -> Kids Gear.

First of all, the GGs (in Japan, anyway) that have a serial number starting with P are probably the newer type (1 ASIC GG); while those starting with B could be the older one (2 ASIC GG). Secondly, the old GG can be distinguished from others by the shape of the LCD screen cover. On old GGs, the cover is totally flat, and has very little bevel along the edges. More modern GGs have a gently curved cover, with well-rounded bevels on the edges.

I would like to add my own observations that there are some GGs (I have a blue and a black one) with serial number starting with B but it still have 1 ASIC. And I'm pretty sure that one major difference between 2 ASIC and 1 ASIC models is that the 1 ASIC models introduced the "PRODUCED OR LICENSED BY SEGA ENTERPRISES" screen BIOS. The older models have no BIOS or screen; they jump straight to the game.

Since I'm sure the guy in Japan reads these forums, I'll add my GG's serial #s to flesh out his table.

Black GG, 2 ASIC, B0360028
Black GG, 2 ASIC, B0103525
Black GG, 1 ASIC, B41024977
Black GG, 1 ASIC, P31070595
Skeleton GG, 1 ASIC, P41240116
Blue GG, 1 ASIC, B41150090

So I guess we can see that B or P is no guarantee of the ASIC, but the number after it is a good indicator... P3, B3 or B4 seem to show that it's 1 ASIC; B0 or B1 seem to show it's 2 ASIC, at least.
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Post Posted: Mon May 09, 2005 10:01 pm
Quote
the old GG can be distinguished from others by the shape of the LCD screen cover. On old GGs, the cover is totally flat, and has very little bevel along the edges. More modern GGs have a gently curved cover, with well-rounded bevels on the edges.


Not so sure, I used to own two GG, one with flat cover and the other with rounded border and the two were 2 Asics versions (at least in Europe), my actual black GG serial 2 Asics is B10126814.
BTW is somebody know if the model number (second line of the serial label) change with versions, mine tell "MODEL NO.2110-50".

Chris, I recheeked my schematic and there is no error on the previously posted one.
The latches are valided during low to high transition so pin 30 is used direcly to command green and inverted to command blue, in other hand the exact behaviour of pin 10 is not know, I can only suppose it's active for red and blue and need to be delayed?
Cheek your DAC resistors connections, I suspect an error here if you obtain incorrect hue.

The more I think, the more I am certain this TV-Gear version work only on a 2 Asics version.
I'll soon receive new components and try a alternate method wich use signal common at the two version (FB1 or other) but I fear it'll need more components, therefore more space...

Xavier
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Thanks
Post Posted: Tue May 10, 2005 2:53 pm
Hi,
Chris:
Nice to meet you. Thanks to transrate my page.

And more thanks your GG version - serial# info. It's very helpful.
Certainly, my 2ASIC-GG is not displays no BIOS screen, that may be indicates difference, isn't it?

xavier:
Thanks for info about your GG, too.

My 3 GG have all same model#, "MODEL NO. : HGG-3210",
they are engraved on GG's back.
I'm looking for your new version GGTV...

I had made one, and now writing report about how-to-make GGTV.
I separated the addon circuit, and put them into battery case.

http://www.sankichi.flnet.org/image/ggtv-back-open1.jpg
http://www.sankichi.flnet.org/image/ggtv-back-open2.jpg

Bye for now.
Sankichi
ggtv-back-open1.jpg (182.81 KB)
ggtv-back-open1.jpg
ggtv-back-open2.jpg (248.46 KB)
ggtv-back-open2.jpg

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Sankichi version
Post Posted: Tue May 10, 2005 3:26 pm
Sankichi, it's impressive!
Just to be sure the 3 ceramic capacitor I see near latches are for decoupling power supply lines isn't?
On my very preliminary schematics I put a 1nF capacitor between each video output and the ground,it was a big mistake because it blur the image too much so I removed them.
I see you use rounded value for the DAC and variable resistor for the RC filter and for TV output. I found 110 ohm is a good value for the RC and 220 for the output. Averal are you satisfied of the picture quality?

Xavier
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Re: Sankichi version
Post Posted: Wed May 11, 2005 1:54 pm
Hi,
xavier wrote

Just to be sure the 3 ceramic capacitor I see near latches are for decoupling power supply lines isn't?
On my very preliminary schematics I put a 1nF capacitor between each video output and the ground,it was a big mistake because it blur the image too much so I removed them.
Xavier


Really?
I had put 1nF capacitors between R,G,B lines and the ground,
I'll try to remove them next time.
It seems that if they are there, the output is not affected so badly.

xavier wrote

I see you use rounded value for the DAC and variable resistor for the RC filter and for TV output. I found 110 ohm is a good value for the RC and 220 for the output. Averal are you satisfied of the picture quality?
Xavier


Yes, I'm very satisfacted.
(but I did'nt measure those variable resistor's ohms)

http://www.sankichi.flnet.org/image/ggtv-output-gh01.jpg
http://www.sankichi.flnet.org/image/ggtv-output-gga201.jpg
ggtv-output-gh01.jpg (32.93 KB)
ggtv-output-gh01.jpg

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Post Posted: Wed May 11, 2005 4:38 pm
Sankichi, that design looks great! I wish I could build something nice and small AND WORKING like that. :/

Did you have no problems with incorrect colours or noise when making your decoder? Since you are using (?) an older design of Xavier's, are you using 74hc132 or 74HC00 (like he typed once)?

Xavier: I finally got a new digital camera today, so I can take pics of my efforts so far. It's a long write-up, so please take a look at a page I made up to show how the GG image looks when connected various ways: http://disgruntleddesigner.com/chrisc/segahacking/ggrgb.html

And if you have any ideas what I am doing wrong, please let me know. Thanks!
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26nm TV-Gear version ;)
Post Posted: Wed May 11, 2005 9:01 pm
I must insist use my last schematic, not the previous ones, they have alls drawback!

I re-re-cheched my prototype with a continuity tester, and it's always the same think, pin30 used directly (or accross two NO gate I this design) command Green latch, and inverted command the Blue latch, this part is the simplest one of the decoder and seem perfectly reliable.

Chris, as far as I can see all you connection seem correct,
Here a little help to connect it:



1
2
3
.
. IC2
.
22
23
24
corner 25 26 27 28 29 30 . .



Even if it can work with 74x00, I highly recommend using 74x132, schimt trigger gate are far more stable against jam.

HC, HCT or F ICs familly are improvement of old CMOS version, therefore their input resistance are HUGE sometimes superior to 1MegaOhms. In such condition any wire connected to an input tend to act as an antenna so I boosted signals with 1Kohms resistor on each input ( the closer of the last TV-Gear IC chain, let my guess, in your case it's the green latche isn't?).
I can't see if you put them in your device.

Sankichi avoid this problem by using very short wire and put the device into GG shell wich is already heavilly shielded.

Remember, we work with very fast digital/parallel data, so the system is very sensible to jamming. I avoided it by burning a pcb with shorter possible connection between gate. Try to reduce wire lenght, it must reduce the noise.

Quote
Here's a close-up of the screen. I think it's clear here that Blue seems to be offset by some amount, perhaps 1 pixel. Hmm... what to do?


Try to change the variable resistor setting, an good average value is near 110ohm.
Just in case verify your monitor color convergence with another RVB console.

Averal, you seem very near of a good result, but cheek if you don't invert a connection at NAND level.

Xavier
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Post Posted: Thu May 12, 2005 2:06 am
Xavier, I'm pretty sure the logic of my NAND gates are correct, so it seems that the problem lies in the unexpected and strange appearance of the data on pins 10 & 30. Did you see the pics I took of those pins going into the decoder? Does that look the same as what you obtained on your Game Gear? (10 = active for red or green; 30 = active for blue.)

I probably won't be able to build this decoder inside of my GG -- I'm just not that talented. When I get the logic working correctly, I plan to connect the GG wires to the decoder board through a DB9 cable. Do you think that would be OK to shield it from noise? And you said I should try to make the connections as short as possible. Is that between the GG and decoder, or just between each of the NAND gates?

Thanks,
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humm
Post Posted: Fri May 13, 2005 10:01 am
Xavier,

my I request that you post a final schematic with all the required info together? Resistors, ICs, whatever... please!
So that way we could have the building stuff easily. Even in the Technical Stuff section as "work in progress..."

Thanks

http://student.dei.uc.pt/~jcgonc
 
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Post Posted: Fri May 13, 2005 2:19 pm
Hi,
ccovell wrote

Did you have no problems with incorrect colours or noise when making your decoder? Since you are using (?) an older design of Xavier's, are you using 74hc132 or 74HC00 (like he typed once)?


I built the circuits based on xavier's schematic of his Wed Mar 23, 2005 7:53 pm article.
http://img131.exs.cx/my.php?loc=img131&image=ggtv25nm.jpg
It was a newest version when I started to test & built them.

Incorrect colour...? Yes, I had a trouble like that, but it might be my mistake...

When the first test-circuit had been constructed, colours were incorrect.
I checked it about for a week, then, I tired and tried to swap the connections of RGB colors...74HCT574 output pins to TV RGB inputs.
Result of several trials, It displayed correct colours.

I uploaded my circuit's connection. I'm grad if it helps you.
http://www.sankichi.flnet.org/image/ggtv-circuit-rev01.gif

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japan/europe scart difference
Post Posted: Fri May 13, 2005 9:32 pm
Quote
my I request that you post a final schematic with all the required info together? Resistors, ICs, whatever... please!
So that way we could have the building stuff easily. Even in the Technical Stuff section as "work in progress..."


Pretty busy actually... my documentation writting is slow, but you can consider the last schematic as perfectly functionnal for the 2ASIC version. I use it since March without any problem.
Of course I can write something for the 2Asics version and wrote later for the 1Asic version.

BTW when I see Sankichi diagram I realised that my own schematic use standard gate drawing, no actual IC connection, wich is pretty hard to understand for a novice, so I must draw something more clear.

Quote
When the first test-circuit had been constructed, colours were incorrect.
I checked it about for a week, then, I tired and tried to swap the connections of RGB colors...74HCT574 output pins to TV RGB inputs.
Result of several trials, It displayed correct colours


Seriousy you and Chris give me a terrible doubt about my mental health ;-)
I re-re-re-cheked my proto and found... no error, do you use scart to connect the TV-Gear to your TV, if so take note that the japanese scart has different connection than the european, the scart's pin given in my schematic is for the european type only!
In any case it's strange you two experiment exactly the same problem ?!?!
( fortunely easy to solve)

Xavier
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Post Posted: Mon May 23, 2005 6:33 pm
Hi folks,

Most of the technical details you guys are speaking of go right over my head, but I just thought I'd ask something, since I don't know what regions of the world each of you live in.

Is anyone here testing this on a PAL monitor of some sort? I'm not sure if this was considered or if it would explain the colors being off.

Xavier mentioned the SCART plugs being different, so I thought that may just be half the problem.

Sorry if I just sound like a newb dumbass, but I didn't see this mentioned earlier.

-Rob
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Post Posted: Tue May 24, 2005 12:14 am
Quote
Is anyone here testing this on a PAL monitor of some sort? I'm not sure if this was considered or if it would explain the colors being off.


Well Rob, it would be a good explanation, if we work with composite video signal ;)
Since we work with separate signal Red, Green, Blue and synchro, we can totally and safelly ignore the composite format ( pal ntsc or secam) as long as the monitor can handle 60Hz video signal.

Quote
Sorry if I just sound like a newb dumbass, but I didn't see this mentioned earlier.


" Seul ceux qui ne font rien ne se trompent jamais."
Théodore de Bainville
*

* Only those who do nothing never make mistake.

Xavier
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Post Posted: Wed May 25, 2005 5:36 pm
Ok, great.

I didn't realize you were all testing these on monitors that handle 60Hz.

Thanks, Xavier.

Best of luck with this project, guys...can't wait to see the outcome.

-Rob
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Post Posted: Wed Jun 01, 2005 4:33 pm
All the work you people have done is great. I always have ideas about projects like this and just loose enthuseasm after my first failure lol.
The reason for my post is to ask about the posibilities of using this circuit to send RGB to the GG LCD. I have some basic electronics knowledge but dont know so much about the types of signals.
Could you use a similar circuit to encode an RGB signal (from DVD player/Amstrad etc) and send the coded signal to display on the LCD? I suppose you would have to disconect the output from the GG to the LCD. But if done right you would be able to switch between normal GG play and external input.
I know people have tried inputting AV signals through the GG TV tuner but has anyone atempted direct video input?

Thanks for your time
 
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Post Posted: Thu Jun 02, 2005 8:32 pm
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The reason for my post is to ask about the posibilities of using this circuit to send RGB to the GG LCD. I have some basic electronics knowledge but dont know so much about the types of signals.


Well Gez, I don't want to be pessimist but such system involve using 3 ADC (analog to digital converter) with fast technologie wich is far more complex and expensive than the actual TV-Gear ( wich do basically exactly the contrary).

You must understand converting a digital signal to analogic is really simple, in TV-Gear case some resistor and latches are enough. Sadly, converting analog signal to digital is far more complex.

15 years ago United Microelectronics Corp (UMC) build a lot of such specialized chips ( for instance the UM70C171 contain virtually all you need to build a TV-Gear) but all this wonderfull chips are no longer avaible.

Trust me,I really recommend you found an old tuner and tweak it as video input, because a self-made video interface will be really, really big and expensive...

Xavier
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Post Posted: Thu Jun 02, 2005 9:27 pm
Thanks for that. i am getting a TV gear off ebay at some point anyway i was just curious if that would work. Im working on some different mods to my gamegear at the moment.
1.I have changed the backlight for LEDs and almost doubled the battery life in the process
2. Im working on iluminating the buttons (not really a usefull feature as after about 2 mins of using it you instictivly know where the buttons are anyway) i just think it would look cool
3. I am adding an internal FM tuner to listen to the radio while playing games :)
Il try to post some pics when im done.
 
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Post Posted: Thu Jun 02, 2005 10:31 pm
If the UM70C171 is not available anymore, what are you folks using to build these? Hope I didn't misunderstand...

Yours,
Rob
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Post Posted: Fri Jun 03, 2005 12:52 am
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have changed the backlight for LEDs and almost doubled the battery life in the process


Sound interresting 8-) but isn't light diffusion hazardous?

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If the UM70C171 is not available anymore, what are you folks using to build these? Hope I didn't misunderstand


Rob, it's just an example, for the TV Gear we use 4 chips and some resistors ( up to 24 depending of your configuration). With the UM chip all this parts was integrated into a single chip. But as you can see we work without it, it's simply bigger... ( BTW I highly suspect a UM70C171 clone to be used in the Sega GGTV).

If you remember the movie "Back to the future 3" one of the little component of the car is damaged during a storm. To replace it Doc must build a huge circuit full of vacuum tube.

I always quote this scene when I must compare specialized chip VS homemade circuit, we can theorically reproduce all behavor but it take more space... and hoppefully in 2005 we are no longer limited to vacuum tube :-p

Xavier
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Post Posted: Fri Jun 03, 2005 3:07 pm
Gotcha, Xavier. :-)

I wonder if any place still has a large stock of those UM chips. :-)

It would be very cool to get these as small as possible, but hey, I'm just glad it actually works.

Vaccum tubes! HA! :-D

-Rob
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Post Posted: Mon Jun 06, 2005 8:57 pm
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Sound interresting 8-) but isn't light diffusion hazardous?


When you say hazardous do you mean dificult? If you mean what i think you mean i solved that problem by cutting the ends off the flourecent bulb and putting the LEDs in either end of that. Then replaced it all as before. Apart from it was hooked to 5V not the huge voltage the bulb used. It all works pretty well. it is slightly dimmer than before and the screen is a bit brighter at the edges than in the middle. But it is still perfectly playable, i havnt tested how long battereis now last but iv had the same ones in for a few days and had at least 3 hours gaming with no sign of them running out any time soon.

As for my other mods, i need to order some 3mm LEDs for the buttons. And the Radio has been troublesome. The signal from the radio isnt strong enough to give a decent volume. and there seems to be some interference between the 2 circuits. I mite put that idea on hold.

Another idea im thinkong of trying it adding a battery level indicator. There is a fair bit of spare room in the GG case for little additions.
 
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Post Posted: Tue Jun 07, 2005 8:02 pm
Why not put another LED in the middle to even it out?

-Rob
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Post Posted: Wed Jun 08, 2005 1:19 am
xavier,

Do you know why TV-GG is not full screen on TV ?
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Post Posted: Wed Jun 08, 2005 1:42 am
Hi Tomy:

It's relatively simple: the Game Gear is the same as a Master System, just with a larger palette. So, it outputs the same resolution and frequencies as a SMS, but since the "active window" is only 160x144, the view is much smaller. The GG when in SMS mode outputs full-screen SMS graphics as usual.
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Post Posted: Wed Jun 08, 2005 5:40 am
ccovell,

Thank you. I understand now. My TV-GG problem same as you. I can not use xavier schematic. It will be color swaped. Don't know why ? I use HC series IC, it is ok, picture acceptable. Thank all guys here.
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Post Posted: Wed Jun 08, 2005 1:29 pm
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take note that the japanese scart has different connection than the european, the scart's pin given in my schematic is for the european type only!


I remember Xavier mentioned this earlier.

Was this compensated for?

-Rob
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Post Posted: Thu Jun 09, 2005 1:46 am
Xavier is talking only about the end of the RGB connector for TVs (21-pin RGB connector). Internally, the Game Gears should be the same, although this has made 3 people so far that have had trouble connecting as per Xavier's schematic. Maybe the Asian/European GGs are different inside? I can't imagine that to be true.

So anyway, believe us, we're not mistaking any lines in the RGB connector; something else is wrong with the connections.

Tomy and Sankichi: if you ever got a good picture from your GG circuit, can you check to see if one of the components (blue, for me) isn't offset by one pixel? For example, in Columns, a purple jewel doesn't have red or blue fringes on its side?
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Post Posted: Fri Jun 10, 2005 12:02 am
Hello friend,
Well so much to say...

Quote
it is slightly dimmer than before and the screen is a bit brighter at the edges than in the middle


It's what I mean, sorry "hazardous" was a wrong word.

Quote
Do you know why TV-GG is not full screen on TV ?


I used to take my screenshot the closer of my TV for better image, it's hard to see it isnt fullscreen ;)

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this has made 3 people so far that have had trouble connecting as per Xavier's schematic


HHHHAAAAAARRRRRRRGGGGGGGG, now it's sure I'm good for asylium...

Seriously I suppose it's my schematics connection wich is false but honnestly it's very strange because I built 2 different prototypes wich use this schematics and it work like a charm !?!? I'll reopen my GG and verify internal motherboard connexion.

Quote
For example, in Columns, a purple jewel doesn't have red or blue fringes on its side?


Chris, I just tried Columns and the purple jewel don't seem abnormal, I'll take some picture to show you but IMHO it's a minor tuning problem, we'll see it step by step:

1) Verify your monitor such color blend happen somethime with old screen. Try with another monitor or TV.

2) try to increase output resistor value, too high output level tend to blend color.
NB: if you use variable resistor for output try to keep the 3 at the same value.

3)Remember the separation resistor, the red one on my schema, try to modifie it with a picture where you see problem. This is VERY VERY sensible and can ruin image if not correctly tuned.

4) If nothing work... well try to post close shoot of your TV Gear component and solder side, maybe you did someting I have not planified when you built it.

Xavier
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Post Posted: Sat Jun 11, 2005 7:18 am
xavier,

I don't know why three people have the same result. Maybe timming problem ?
Because I connect 4 data lines to the end of resistor, then it is ok.
But if I connect 4 data lines to the point between resistor and capacitor. Then color have big problem.

ccovell,

I checked "Columns", yes, look like one pixel offseted of blue. But picture is ok, no big noise.
But I can not make sure color is right or not. Can you send me your sample code for me to test color ?
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Post Posted: Sun Jun 12, 2005 4:12 am
Hi, folks. Tomy: I did make a Game Gear demo that shows many colours; you could use that. http://www.zyx.com/chrisc/creations.html

Or if you just want simple RGBCMY colour bars, I could send you a small ROM, but it is simply a modified version of your SMS Flash menu program. :-)

**UPDATE**

I finally figured out what was causing the interference: I had connected the data lines on the wrong end of the resistors, which caused this. It was this pic (http://www.sankichi.flnet.org/image/gg-asic2-board.jpg) which finally clued me in, although in that picture the connection for D0 is on the wrong end of the resistor.

Now having soldered the data lines correctly, I get an almost perfect picture on my monitor! (No offset blue component, either.) The hard part is over. Now I just need to get some smaller-value resistors because the pot for separating the components is very sensitive -- the resistance range needed to keep blue without losing red is very very narrow.

The only problematic thing that I can see now is that my green component is too bright. Maximum green is the same brightness as the other components (giving white when mixed), but dark green is much brighter than the other components, making greys appear greenish, and oranges appear yellowish. Hmm... I checked the resistances of all my resistors, and they're the same; I wonder why green is out of whack.

Anyway, I'll work on this some more tomorrow, and then start taking pictures. =-)

Success! (Sorry for driving you crazy, Xavier.)
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Post Posted: Sun Jun 12, 2005 6:23 pm
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Sorry for driving you crazy, Xavier


Noooooooooooooooo problem, just a little headache ;)

Happy to hear your problem is resolved.
For the incorrect green there is 99% chance you green DAC is shorted or one DAC resistor value is incorrect, it's easy to mistake 270ohm with 2,7 Kohm for instance

for the blue/red adjustment, Try to find a "multitour" ( don't know english word, multiswap?) pot. If we consider the correct value at 110 ohm ( at least with HCT it can be LIGHTLY different if you use HC or F technlogies) then you can use a standard resistor of 110 ohm 1% precision, or a pot of 300ohm or more.
Like you say the correct range is very narrow.
Personnaly I used "Sonic triple trouble" title screen for my tuning ( light/dark blue sonic, light pink skin, dark pink knuckle and red title: PERFECT)

Xavier
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Post Posted: Sat Jun 18, 2005 3:53 pm
I'll keep searching for a good resistance to use for the pot. For now, though, I'm very happy with the picture from my GG, so much that I've updated/made a new page showing the TV Gear project and plenty of screenshots.

http://www.disgruntleddesigner.com/chrisc/segahacking/ggrgb.html

Enjoy the piccies!
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Post Posted: Sun Jun 19, 2005 9:41 pm
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Enjoy the piccies!


Chris, just a quick word:

BEAUTIFULL :)
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Post Posted: Mon Jun 20, 2005 2:24 pm
That's great, Chris! Congrats on figuring out the errors.

So are there anymore outstanding issues/problems with the circuits?

Anyone care to post finalized circuit diagrams?

-Rob
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Post Posted: Tue Jul 19, 2005 5:31 pm
Hi folks,

It been about a month or so, so I figured I'd bump this a bit to see if there's any news on this since the last posts. :-)

-Rob
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Post Posted: Wed Aug 03, 2005 12:12 am
Maybe it's time to store this stuff/all developed in the documentation area?
 
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