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[Plaz]

Back when the discussion started about the scan doubler built by Roy Justus, I wrote Roy, ask for and received his documentation. He graciously provided his documents, but they were made with custom tools and libraries so they were incomplete when I tried to use them.

I really really wanted to get off of ntsc monitors, so this looked like the prefect oportunity to build my own doubler if I could work out the details. With a bit of a "bee in my bonnet" I went to work completing the schematics and designing the PC board.

After several weeks using what spare time I could scrap up, I came up with a more Amiga specific version of Roy's design. Have a look here for a screen shot of the proto board work up (Rev5-G)....
AmiDoubler Proto

Roy explained that he was swamped in orders and if I wanted to make some of these and sell them, fine by him. It sounded like a great idea, but my spare time is tiny and the cost to set a small production run would kill me. So with the minimig and GB A1000 projects in mind I post the subject here for discussion.

Advantages of the design....

Can plug directly into the video port of any Amiga model leaving clearance for other connectors, or an extention cable can be used.

Only needs ~5 1/2 inches (14cm) clearace from the rear of the computer to any obstacles like walls....

Small compact size

The PIC chip can be reprogrammed while installed. (with proper cable)

Hey, designed by Plaz

Disadvantages

Unusual layout needs a custom case/cover possibly making it more expensive.

16bit, not 24 like the one Jens is reported to be working on.

Hey, designed by Plaz :-)

Plaz

[amigadave]

The GB A1000 has the option to install an Amber chip scan doubler/flicker fixer on board and the MiniMig has a scan doubled VGA output included, so those two projects do not need such a design as yours, but I am sure there are many A500 & A1000 owners out there that would love to have a reasonable cost scan doubler. What is the estimated cost to produce your design?

[rkauer]

Like I said b4, I'll love to grab that schematics to give it a try. ;-)

And even if the board doesn't do 24bit, who cares? All (I say) external SD that everyone made for Amiga are 16bit!

Case... hmm... What about one "Minimig-look"? Two sheets and 4 spacers and nothing more?

[alexh]

amigadave wrote:
I am sure there are many A500 & A1000 owners out there that would love to have a reasonable cost scan doubler.

AFAIK the chips (Denise) in the A500 and A1000 are socketed meaning you could easily make an INTERNAL version of this scandoubler using just HALF of Plaz's design.

It would be cheaper and MUCH better quality without the first of the Digital->Analog->Digital->Analog conversions.

Ditch the AL875 and add a DIL socket & plug for the denise et al.

[amigadave]

alexh wrote:

AFAIK the chips (Denise) in the A500 and A1000 are socketed meaning you could easily make an INTERNAL version of this scandoubler using just HALF of Plaz's design.

It would be cheaper and MUCH better quality without the first of the Digital->Analog->Digital->Analog conversions.

Ditch the AL875 and add a DIL socket & plug for the denise et al.

Provide a design, test it for proof of concept, make a prototype to show it can be done and that it works, then many of us will follow your lead and build our own copies of your design. :-D

[Plaz]

Ditch the AL875 and add a DIL socket & plug for the denise et al.

Hmmmm, good idea. I'm concerned about the lack of demand if the Jens model is release soon though. It would be more work for an inferior unit.

Plaz

[Plaz]

so those two projects do not need such a design as yours

Yes, of course. This was ment for original 500/1000/2000/4000 boxes only.

Plaz

[Plaz]

I'll love to grab that schematics to give it a try.

Check your mail. The proprietary software makes it harder to share in file form unless you use the vendors software though.

Plaz

[alexh]

WTF? Proof of concept? How lame are you? :-D

http://aminet.net/package/docs/hard/pinouts

Denise:

Pin19 = Vcc (+5v)
Pin37 = Vss (Gnd)

Pin20 = Digital RED(2)
Pin21 = Digital RED(3)
Pin22 = Digital RED(4)
Pin23 = Digital RED(5)
Pin24 = Digital Blue(2)
Pin25 = Digital Blue(3)
Pin26 = Digital Blue(4)
Pin27 = Digital Blue(5)
Pin28 = Digital Green(3)
Pin29 = Digital Green(4)
Pin30 = Digital Green(5)
Pin31 = Digital Green(6)

Pin32 = Composite Sync (A1000 = Pin39 on Agnus)
Pin36 = CCK

Just wire up these signals to the AL250 as if they were coming from the AL875 you will need to sync separate which is very easy. (During early development it would be simple to use HSYNC (38/79) and VSYNC(40/81) off the Agnus).

Tie off the missing RGB 565 input LSB's to GND

Internal scandoublers for the A500 / A1000 are nothing new.

ICD Flicker-Free video

There is a nice manual here.

Be careful with the physical size of the PCB

[Plaz]

Just wire up these signals to the AL250 as if they were coming from the AL875 you will need to sync separate which is very easy.

Given what I've worked out so far, this doesn't seem like that big of a deal to use Denise for an internal version. Exactly why have we been waiting years on a new doubler?

Plaz