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Why I still haven't done Gryzors Atari ST HxC mod.

Started by Bryce, 11:58, 21 April 14

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Bryce

Hi all,
     one of the reasons many of my projects get delayed so much is because I tend to get easily distracted... Oh look a butterfly....
Yesterday I planned to finish and test a mod I was doing for Gryzor, but when I went looking for a connector I ended up finding a small screen I bought a while back for a different project, but turned out not to be suitable, so it was still lying here in a box. Rather than passing it by I spontaneously decided to make something out of it. So here it is. My Portable retro computer screen.
Those who know me better will know that I spend a massive amount of my time stuck in Hotels where retro programming and gaming is difficult. This might be my answer :)

[attach=2]

The screen is 10.9cm (4.3 inch) and has a resolution of 480 x 272, so it has enough pixels to give a sharpish CPC picture.

[attach=3]

The pictures don't really do it justice, the screen is quite readable in Mode 0 and mode 1, but I wouldn't try using it in mode 2.
For gaming it's fine.

[attach=4]

I had space in the case to add some stuff. So I did...

[attach=5]

Starting from the top it has S-Video In, Composite In and RGB In. I used the CPC+ connector and pinout for RGB In and I intend adding an internal speaker later. The other big DIN is Power In. It's designed to work with a Spectrum +3 PSU which supplies all a CPC needs. The flylead is 5V Out with connectors for the classic and plus CPC. The socket above the flylead is 12V Out for the 6128.
The lower switch is to choose S-Video / Composite or RGB. The other switch doesn't have a function yet. I may add a green screen option on this switch later.

Now today I REAL DO INTEND TO DO YOUR ST Gryzor. Honest! :)

Bryce.

Gryzor

Super cool! I guess it's got its own separate power supply?

Also, how possible is it to have both this and the CPC monitor active? Sure, no sense in it, but since the only sense it's got is look fucking cool, I thought it'd look even fucking cooler if you had TWO monitors on the CPC!

Now, if that was the only reason my ST got delayed I'm sure I'd be ok with that...

Bryce

First off, your ST is finished and ready to go now.

The screen is powered by a Spectrum +3 PSU and passes the 5V / 12V on to the CPC too. It doesn't display on the mini monitor AND the main monitor at the same time, although that would be possible by adding a small circuit.

I've already made use of it to test your ST while my main monitor was displaying CPC stuff :)

Bryce.

Gryzor

Is there a screen small enough to fit where the drive of a 6128 is? I guess you can at least do it with a Plus? Awesomeness...     

Bryce

You can get tiny screens, but 10cm is about the limit if you want it to be readable. I've been looking out for one of these: http://images.cqout.com/SB/siemens_Optiset_E_Memory_white.jpg (we used to use these at work). The flip-up screen bezel is the right size for the screen I used and the colour is the same as the plus and the curve is even correct! I was thinking of integrating it in the centre of the plus case to make a flip-up screen. It may even fit without having to edit the cartridge slot or floppy drive.

Bryce.

Gryzor

But... you don't really need it to be readable because, let's face it, even if it is it's not practical. IT'S JUST FRIGGING AWESOME!

And yea, that screen looks sweet...

Bryce

I have a project (not saying more at the moment) where I intend writing the assembly code for it myself, so I need it to be readable.

Bryce.

Gryzor


Bryce

I'd like to get back into assembly coding. I used to be quite fit in 6800 coding, but that's a loooong time ago. So I have two ideas (hardware projects) that would require ROM based software and I intend to write the code myself. Even if the projects aren't interesting, you can all have a good laugh at my assembly attempts :D

Bryce.

beaker

Nice, any chance of seeing the ST mod as well?  :)

Bryce

I didn't take pictures of it and it's now packed and ready to go.

Bryce.

Gryzor

Quote from: beaker on 00:01, 23 April 14
Nice, any chance of seeing the ST mod as well?  :)


Ah, but it's not much, one of those things Bryce does while having breakfast. Just a cable to connect a HxC to the ST's floppy port, but the problem was the non-standard and bitch-to-work-with format.

Bryce

I added internal S-Video Out and Stereo Audio Out ports too :)

Bryce.

beaker

Sounds like good mods  :D I was curious as I am thinking of going for an STe and was wondering what to do with it after putting the HxC internally in my ST. 

I tell you what, that monitor would look cool in the Tatung, there's probably enough room in the body to put it internally and then have it rise on linear actuators when you turn it on.... how cool would that be?  :laugh:

Out of interest is there any way to cheaply and easily convert an S-video signal into RGB? The signal would have to be resampled and the colours split out I guess? Would the result be any good? My Sony Trinitron doesn't support S-video which is a pain with my Wonder Mega, FM Towns Marty, and (ahem) C64's (although I am using composhite with that)...

Gryzor

Awww so that was going to be a surprise? :)

Where do I send the flowers?

Bryce

There are ways of converting S-video to RGB, but they aren't easy. The simplest way is to use something like the Philips TDA3560/1 PAL Decoder. These are old 28pin ICs that were used in Colour CRT TVs. Essentially a CRT TV usually did the following:

- Demodulate UHF to Lum/Chrom/Audio (Done in the little metal box right behind the UHF socket)
- Split Lum/Chrom into RGB for the 3 CRT colour guns and send it to the CRT Amplifier (Done by the TDA3560)
- Separate Audio and send it to the Audio Amplifier.

The TDA3650 is essentially an S-Video to RGB converter. You can probably find one on ebay for a few Euros. But...

- It needs a huge amount of external analogue circuitry, that has to be tuned.
- It needs a delay line (this was a piece of glass used to add a signal delay, almost impossible to find these days)
- The outputs were made to drive a CRT, so the output levels are all wrong.
- It outputs a "Sandcastle pulse", not a sync pulse, so this would have to be converted.
- It needs a 12V supply
- The picture would be crap

Some references:
TDA3651 Block Diagram: http://3.bp.blogspot.com/_SPwX1vYEKqg/TPu7xLBlQHI/AAAAAAAACuQ/cP4qTqz82_I/s1600/tda3561a.jpg
Picture of an opened delay line (Yes there really was one of these in everyones TV :D ): http://farm4.static.flickr.com/3169/2840365262_837223d907.jpg

Bryce.

Can't you fit a 26in CRT inside the Tatung? It should be big enough. :D

Bryce

Quote from: Gryzor on 13:19, 23 April 14
Awww so that was going to be a surprise? :)

Where do I send the flowers?

I thought I mentioned that to you :)

Bryce.

Gryzor

If you did, I totally forgot. Where's that S-vid cable of mine, dammit!!!!

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