Output to VGA?

[Mangelore]

Seriously though - looking good - you plan on building & selling these as a completed item ? If so, you've got your first order! (My 1081 has finally died & I'm using a Commodore 1701 at the mo - so only can do 40 columns).


Cheers,

Lance

At this point in time it's more of a personal project. It cost me US $90 for the board so it's not that cheap. I'm still investigating options to turn it into an all-in-one solution (40 & 80 column) and possibly source it directly from the manufacturer. I'll keep you guys updated.

Cheers
Fotios

[hydrophilic]

Nice case and wiring job.  Looks real professional.

[Mangelore]

However, the most serious limitation with this board is that it only supports the first 8 available colours. The reason it can not display the full 16 available colours is due to the lack of support for the Intensity pin available on the C128 RGBI output.

Hi guys,

Just a quick update. As you'll notice from the above comment,  the converter board I'm using is RGB to VGA and not RGBI (I for intesity) to VGA. So, I've been studying the board trying to figure out how to modify it to support the full 16 colour palette of the C128 80 column mode. I created two add on circuits. The first one didn't work :gråta: but the second one which is very simple in design seems promising. I'm now able to display all 16 colours on the screen! :skratta: However, I need to fine tune it a little. Fingers crossed...

Fotios

[Mangelore]

Some more good news.

All 16 colours are now displayed in a perfect manner on my VGA screen! :tummenupp: The solution was so simple it's laughable... My initial modification interfaced the Intensity signal directly into the RGB analog inputs of the surface mounted Analog Devices chip found on the ACV-011 board. There were a number of resistors and capacitors between the RGB TTL inputs and the analog inputs of the AD chip. While the 16 colours were all on the screen, the brightness was bleeding too much. So, I then interfaced the Intensity signal just after the first analog conversion stage with a few resistors and it worked like a charm.

I'll post a few screen shots in the near future.... Now it's time to convert the 40 column mode to VGA.

[nikoniko]

Great job, Fotios! :hurra:

[Mangelore]

Howdy,

Well, some more good news... I managed to locate a supplier who's willing to bulk sell the converter board at discounted rates. If I was to sell this as a finished product it would probably go for between US$100 and US$150. Now, I realise this is a big price to pay for hooking up the C128's 80 column video output to a VGA monitor so here's some more good news....

I just managed to hook up an Amiga 500 to a VGA monitor with excellent results. So, my plan is to offer this as a solution for both C128 and Amiga 500 users. Now, I haven't tested all possible Amiga screen modes but the few games I tested worked fine.

Two photos of Stunt Car Racer and SpeedBall 2 running on an Amiga 500 hooked up to a VGA monitor have been uploaded.

Do you think this product will be of interest to some?

Looking forward to your feedback.

Oh, here are the links to the new screenshots

http://img155.imageshack.us/my.php?image=stunt1ez5.jpg
http://img155.imageshack.us/my.php?image=speed2ko2.jpg
http://img206.imageshack.us/my.php?image=risen1xs0.jpg
http://img242.imageshack.us/my.php?image=risen2aa0.jpg
http://img263.imageshack.us/my.php?image=risen3vv2.jpg

Cheers
Fotios

[Blacklord]

Do you think this product will be of interest to some?
Fotios

I'll pre-order two - one for the 128 & one for the 1200.

cheers,

Lance

[Mangelore]

Do you think this product will be of interest to some?
Fotios

I'll pre-order two - one for the 128 & one for the 1200.

cheers,

Lance

No worries. Let me find some time to test my A1200 first. I need to get it out of storage. I have a diagnostic program that cycles through all the A1200 screen modes. It'll be interesting to see how the hi-res interlaced screens show up. Fingers crossed...

Cheers
Fotios

[adric22]

Forgive me if this was mentioned and I did not see it.  But does this device convert analog RGB to VGA?  After all, I know the Amiga has both analog and digital RGB output.. which one are you using?

Now.. I'm still a little thrown off by this and the previous arguments being made against the device I'll be constructing in a few days (when my board arrives)  Essentially this RGB converter happily lives with the sync of a C128 or an Amiga.. which I've been told are different and that is why I'm told my idea for a RGB to S-Video or Component video will not work on the C128.  

Still.. it is great to see something that works besides an original Commodore or CGA monitor.  $100 isn't too bad to pay considering what it costs to purchase an old monitor and have it shipped to you in once piece.

[Mangelore]

Forgive me if this was mentioned and I did not see it.  But does this device convert analog RGB to VGA?  After all, I know the Amiga has both analog and digital RGB output.. which one are you using?

Now.. I'm still a little thrown off by this and the previous arguments being made against the device I'll be constructing in a few days (when my board arrives)  Essentially this RGB converter happily lives with the sync of a C128 or an Amiga.. which I've been told are different and that is why I'm told my idea for a RGB to S-Video or Component video will not work on the C128.  

Still.. it is great to see something that works besides an original Commodore or CGA monitor.  $100 isn't too bad to pay considering what it costs to purchase an old monitor and have it shipped to you in once piece.

While the board is sold as an digital RGB to VGA converter it can easily be adapted to support analog inputs. There's a number of circuits on the boards with specific tasks summarised below.

Circuit 1: Digital inputs are converted to analog
Circuit 2: Timing circuit for various H/V sync inputs selectable using dip switches
Circuit 3: Analog RGB to Flat Panel Display converter IC
Circuit 4: Scandoubler

For the C128 80 column mode I used the digital inputs and interface the intensity signal through a simple resistor diode circuit soldered directly to three spots in Circuit 1 on the board. I've added a variable trimpot to adjust the level of intensity.

For the Amiga 500, I interface the analog Amiga RGB signals directly to another three locations on the board. The digital H/V sync signals from the Amiga 500 are interfaced directly to the digital inputs of the board. This way I can use the dip switches of Circuit 2 to select optimum display output.

I tried using the Amiga digital RGB outputs but lots of colours were missing... more like an 8 colour Amiga It's possible that one of the digital RGB singals wasn't wired up correctly but I'm happy to use the analog ones.

I already have a circuit design for C128 80 column RGBI to composite PAL colour output. It only uses two ICs so is very cheap. The output quality is similar to that of the monochrome C128 RGBI output on pin 7. The only difference is it's colour. Sorry, no NTSC at the moment. I thought there would be more interest in VGA output than composite or S-Video for the 80 column mode.

Cheers
Fotios

[DMode]

Thanks to Mangelore and others for the awesome work helping to make VGA a reality on the Commodore 128!

I received my CGA-to-VGA converter board in the mail yesterday, then immediately ran out to Fry's Electronics to pick up a project box and VGA cable.  I'm also using a composite-to-VGA converter for the 40-column output, so it's pretty much a total solution!

Here's a link my current setup...

http://home.comcast.net/~kkrausnick/c128-vga/c128-vga.html

Now if I can just get Mangelore to provide details for the Intensity pin hack , that will rock!

-DMode

[Mangelore]

Thanks to Mangelore and others for the awesome work helping to make VGA a reality on the Commodore 128!

I received my CGA-to-VGA converter board in the mail yesterday, then immediately ran out to Fry's Electronics to pick up a project box and VGA cable.  I'm also using a composite-to-VGA converter for the 40-column output, so it's pretty much a total solution!

Here's a link my current setup...

http://home.comcast.net/~kkrausnick/c128-vga/c128-vga.html

Now if I can just get Mangelore to provide details for the Intensity pin hack , that will rock!

-DMode

That's just awesome! Great to see you've also had success with this board as well.

In regards to the Intensity pin hack, there's still one issue which I won't be able to resolve. The outstanding issue has to do with the inability to display the brown colour. Instead of brown, the RGBI converter will display dark yellow. The reason for this is listed on Wiki
http://en.wikipedia.org/wiki/Color_Graphics_Adapter

Here's the relevant section:
There is some confusion regarding color #6 on RGBI monitors: If one strictly follows the RGBI color model, color #6 would appear as dark yellow (#AAAA00) (see below). However, IBM chose to include additional circuitry in the 5153 color monitor to detect color #6 and lower the green component to yield a more pleasing brown-tone (#AA5500), so most "CGA compatible" monitors do the same.

DMode, can you please PM me your e-mail address. I want to ask you a few questions regarding your setup and if you're able to run a few tests for me.

Cheers
Fotios

[nikoniko]

However, IBM chose to include additional circuitry in the 5153 color monitor to detect color #6 and lower the green component to yield a more pleasing brown-tone (#AA5500), so most "CGA compatible" monitors do the same.

Might be more pleasing, though it's a little odd to have all the other colors come in light-dark pairs except for yellow. If they were going to mess around like that, I could have done without bright purple myself.

[DMode]

With Mangelore's kind help, I was able to get all 16 colors displayed!

http://home.comcast.net/~kkrausnick/c128-vga/c128-vga.html

Goodbye CRTs.  

[Stephane Richard]

Wow, nice and crisp as expected from an LCD ;-).  This is an awesome project :-).  Now I'll only need to buy myself a C-128 and one of those ;-)

[xlar54]

In all seriousness.  Put me on the pre-order list.  Will send check, cash, money order, first born.

Ah man... I just spoke to the wife... you can't have cash...

 Seriously, count me in if you're building to sell.

[xlar54]

Man... I cant get over this.  After all this time of "it'll never happen", this is huge.  In my book, you guys get the Commodore Hacker of the Year award!

[Mangelore]

Hi, if anyone is interested in this converter, please drop me a PM as there's a few things you need to be aware off.

xlar54, check your PM.

Cheers
Fotios

[Golan Klinger]

I'm not clear on how one goes about getting one of these...

[Mangelore]

I'm not clear on how one goes about getting one of these...

Howdy,

Well, you can purchase the RGB to VGA converter board from here
http://www.converters.tv/products/cga_to_vga/77.html

But the good news is that I have a few of these and will supply them to members of this forum with the Intensity bit (RGBI) modification and DB9 plug for only US$ 81.50.

Shipping to the U.S. via normal airmail is US$7.00, but I'd recommend using registered airmail (with insurance) which costs another US$6.50. So, the total is $95.00

However, please PM me first as there's a few gotchas you need to be aware of.

[xlar54]

You have my attention.

I sent you an email.  Would love to work out an arrangement on buying one of these.  Let me know!

X

[Doppie1200]

Is there any way I can get one of these nice CGA converters here to Holland?

[Mangelore]

Hi guys,

I no longer have any converter boards left. Due to the interest generated I might try to source a few more.

Anyway, here's a quick guide on how to modify the board. As you'll discover it's not that difficult to do. The parts required are three diodes and three 680 Ohm resistors.

Solder the supplied header cable to the DB9 C128 Plug.
http://img442.imageshack.us/my.php?image=cablewz0.jpg

Locate the three variable resistors on the converter board and set each of them to 680 Ohms.
http://img442.imageshack.us/my.php?image=topkx0.jpg

Turn the board over and locate the three pins where the Intensity hack is soldered to.
http://img442.imageshack.us/my.php?image=bottom1tw8.jpg

Solder the three diodes and resistors as per the instructions in this photo.
http://img442.imageshack.us/my.php?image=bottom2tb8.jpg

Now, there's a few issues you all need to be aware of.

- You must power up the C128 computer before powering up the converter boards.
- Interlaced screen modes are not displayed on LCD monitors (at least the ones I tested).
- Interlaced screen modes are displayed on CRT monitors but continue to flicker. While this product is a scan doubler, it's not a flicker fixer.
- Certain screen modes are displayed using a frequency of 50Hz. Some monitors will only scan down to 60Hz.

Enjoy!
Fotios

[Doppie1200]

Why is it that you need the C= switched on before the converter? Does it fail to catch the sync if the C= is not on on powerup?

[Mangelore]

Why is it that you need the C= switched on before the converter? Does it fail to catch the sync if the C= is not on on powerup?

I'm not 100% sure what the root cause is. However, the output image isn't displayed correctly if the C128 is powered on after the converter. I use a momentary push button switch (push=open) inline with the power source as a reset button for the converter.

I've only noticed this issue with the converter when used with a C128.