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F18A MK2


matthew180

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1 hour ago, INVISIBLE said:

... I'd be willing to bet many people would be happy with only VGA if it would get it to market faster.

At this point it is a done deal unless there is some problem passing the digital red and green color bits through the TMDS EDS protection clamps.  I'm not expecting any problem, but we'll see.  The Rev K boards were sent to OSHpark two days ago, so I should have them in 10 days or so.

 

It kills me that the headers are as big as the MK2 itself...  So be it, I can't do much about the size of the connectors, and I'm done fretting over it.

mk2_dvi.png

mk2_k.png

mk2_vga.png

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I would, personally, prefer a mounting plate.  Carefully cut out an opening, then 1/2" to 1" 'away' from the openings, drill mounting screws.  Less strain on the plastic, and you don't have a "tail" hanging out the back of your machine.  I'm assuming that this one also disables the normal composite output as well. IIRC, the signal was originally produced by the chip this is replacing.  I could be wrong about that, but I'm fairly sure I remember that the MK1 disabled it.  Been to long since I read up on the MK1....

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21 minutes ago, RickyDean said:

Can't you go to vga from DVI, I thought you could get adapters for almost any newer video interfaces?

SORT OF.

 

 

DVI connectors CAN carry analog video signals, but aren't required to. If they don't, then a simple plug-and-cable adapter won't get you anything and you need a box of electronics just like you would for HDMI.

 

The digital signal portion of DVI, however, is virtually always there and is almost identical to HDMI(HDMI being built atop DVI, with intercompatibility as a goal initially), so converters for DVI->HDMI are always cheap plug-and-cable affairs.

Edited by JB
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16 hours ago, GDMike said:

You don't want to encase it? Just asking my 2 cents

I'm not sure I understand what you would encase?  The MK2 is a 40-pin DIP that goes into the original VDP socket.  The headers are also the same board size, i.e. 52mm x 19mm (2" x 0.75") and are mean to remain *INSIDE* the host computer.  The 22-pin FFC cable is not designed for external use, and you *will* cause damage if you decide to go that route.  Yes, the DVI and VGA connectors and the header boards are big, and it will be a challenge to mount them in some computers; but I can't solve this problem for every possible computer.

 

13 hours ago, Pheonix said:

... Less strain on the plastic, and you don't have a "tail" hanging out the back of your machine. ...

I don't totally follow the mounting you are describing, but these headers and the cable from the MK2 to the header are not designed or intended for external mounting, as I mentioned above.  I don't like headers, but I don't have any other choice, and in a full year of trying to come up with a solution, and soliciting input from the forum, this is the design that allowed me to go forward.

 

13 hours ago, Pheonix said:

... I'm assuming that this one also disables the normal composite output as well. ...

The original video signals from the 9918A/9928/9929, etc. are *not* generated by the F18A or the MK2.  If you want the original video signals then you don't need the F18A.  The primary function of the F18A and MK2 are to get an updated video signal to be able to continue to use our retro-computers with modern displays.

 

7 hours ago, djones60 said:

I do like the idea of a VGA adapter.  Hope that comes to be, or is maybe a later option

The graphics images of the MK2 and the header boards I posted are not just fancy drawings, they are generated by KiCAD (the open source PCB software I use) and are renderings of the boards as designed.  I have sent the board files to OSHpark (PCB service) to have prototype boards made.  The VGA board *has* "come to be" (it was one of the main board design changes I have been working on for the last 2 or 3 weeks), and I'm just waiting to get the boards from OSHpark so I can build and test them.

 

6 hours ago, RickyDean said:

Can't you go to vga from DVI, I thought you could get adapters for almost any newer video interfaces?

Yes, the full DVI spec / connector have the VGA Red, Green, Blue, Horz, and Vert pins in an analog section, and they can be separated with a passive DVI to VGA cable.  The reason I can't use those pins, and it is killing me to not be able to, is due to space on the MK2, accessing enough of the FPGA's I/O, and the number of pins available on the FPC connector.  I just don't have enough room to pull it off.  I have to dual-purpose the TMDS signals to carry the red and green signals for VGA.  And I can't get access to enough of the FPGA's pins to get an additional 12 output required for a separate VGA interface.  So it has to be TMDS *or* VGA.  Sucks.

 

Staying in the confines of the 40-pin DIP outline of the original VDP has been a very big challenge with the MK2, especially since it kept feature-creeping.  But the board size is one of the primary design goals of the MK2 and eliminates a lot of the physical compatibility problems of the original F18A.

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1 hour ago, matthew180 said:

I don't totally follow the mounting you are describing, but these headers and the cable from the MK2 to the header are not designed or intended for external mounting, as I mentioned above.  I don't like headers, but I don't have any other choice, and in a full year of trying to come up with a solution, and soliciting input from the forum, this is the design that allowed me to go forward.

 

Not to scale and very crude, (not much of an artist,) but something like this:

 

Mount.jpg

 

Manufacturing it would be a problem, though.  Probably too much, but a measurement accurate template would be nice :)

 

Edited by Pheonix
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You can probably get those as standard DVI PC back-plate brackets, and just drill a single hole for the audio, and maybe the two wider holes.  But this will be up to each person.  The MK2 itself is plug-n-play if you have a socket for the VDP, but making the header fit in your computer is a personal mod that everyone will need to figure out.  The original F18A came with a stock PC back-plate bracket for the VGA connector, but that is *only* because it was part of the pig-tail assembly I found.

 

Something like this did not take much searching to find:

 

http://www.amazon.com/Profile-Height-Bracket-S-Video-Graphics/dp/B0056RCSFW

 

 

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3 hours ago, matthew180 said:

Something like this did not take much searching to find:

 

http://www.amazon.com/Profile-Height-Bracket-S-Video-Graphics/dp/B0056RCSFW

 

 

To be fair to questioner, that is $12.50+tax to the doorstep. You might consider the 50 cents to offer a small PCB with no functionality other than to be that shape and offer a nice finish with your product name and website on the silk layer. You'd save your customers a bunch of hassle, and if they didn't want to advertise they could reverse it, and/or paint the back to match their case. I suspect people would love to give you a couple of bucks extra to not have to pay $12.50+ to mod a part that still needs painting to match anyway...

Just a thought.

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7 hours ago, Pheonix said:

I would put the piece on the inside of the case if there is room.  Less cutting into the case that way.  An opening for the DVI & Audio plug and 2 small screw holes.  Only the screws are visible on the outside, and black screws are fairly easy to find.

 

 

A paper template would be nice, that way all a person would need to do is attach it with a glue stick.  Once attached, they could use a Dremel to make the appropriate holes in the correct places for screws, as well as the audio and video connectors.  After cutting, water removes the template leaving no traces.

 

You know, even if a person cannot find black screws, I've found black fingernail polish from the local Dollar Tree works.  ?

 

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11 hours ago, Pheonix said:

If the placement is accurate with the back plate you linked, then that works great :)  Just cut off the right angle at the end and drill 2 mounting holes.  The that can be used as a template to modify the case.  It's the measuring for placement that defeats me :(

For my F18A Mk1, this is more or less what I did.  I cut the back plate down, drilled a hole in it for the audio socket and placed it on the inside of my ColecoVision to provide strength.  I used the back plate as a hole template.  Had to buy longer VGA hex head screws but I was very pleased with the final install.  I also added a small switch so I could flip between the original 4 sprite limit and the F18A 32 sprite limit (USR1).

 

If you need to create hole templates then I use Front Panel Designer software and print to paper.

 

 

 

 

DSC03414.JPG

Edited by Ikrananka
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13 hours ago, Pheonix said:

 

Not to scale and very crude, (not much of an artist,) but something like this:

 

Mount.jpg

 

Manufacturing it would be a problem, though.  Probably too much, but a measurement accurate template would be nice :)

 

I've lasered a DB9 screw-mounting plate out of acrylic/wood. It has worked well for my arcade controller.

Though my F18A mk1 was kind of messy (melted holes with soldering iron, filed, cut down the VGA back plate, screwed it in)

Next time I will make a nice acrylic plate that can go inside or outside of a rectangle opening. I will use acrylic cement, though super glue should work. We have plenty of the self-drilling screws used in the console itself , I wonder if those are too big to use.

 

When the time comes I'll give my plate away for free (though Greg is welcome to sell them)

 

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On 2/21/2020 at 1:04 AM, matthew180 said:

However, the MK2 will have the audio enhancement since that is part of the hardware; so start preparing now if you can't solder.  You will need to get a wire from the computer's internal audio to pin-1 of the MK2 board.  On the 99/4A a good place to pick up the audio is L201, on the CV it is C88.  The MK2 has a 12-bit ADC that converts the audio into digital, and then spits it back out via a 12-bit DAC to the header's audio line-out.  Since the audio is brought into the FPGA, that means the GPU can mix, modify, replace, or do whatever with the audio data on its way out to the DAC.  This basically gives the MK2 12-bit audio capability on top of the system's existing audio.  The GPU audio is not yet designed, so I'm considering any suggestions at this time.

Is the audio output stereo?

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4 hours ago, Asmusr said:

Is the audio output stereo?

It is not.  Stereo would mean more hardware, more cost, and another audio pin on the connector that I just don't have.

 

However, the MK2's audio features are not yet defined, other than they are 12-bit and there will probably be direct access to the input audio data (that means full control over the original system's audio, mixing with new audio streams, control volume, add envelopes, etc.)

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43 minutes ago, matthew180 said:

It is not.  Stereo would mean more hardware, more cost, and another audio pin on the connector that I just don't have.

 

However, the MK2's audio features are not yet defined, other than they are 12-bit and there will probably be direct access to the input audio data (that means full control over the original system's audio, mixing with new audio streams, control volume, add envelopes, etc.)

Just give us a register in the GPU and let us worry about the implementation. ;)

 

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  • 2 weeks later...

The Rev K boards came in today, and the parts were in last Wednesday.  It is too late tonight, but I'll probably build one tomorrow and see if I fixed anything.  I'm also working on moving my website, CodeHackCreate is migrating to dnotq.io.  The new site it up but not done.  I'm trying to make it more useful and easier to maintain and update, so hopefully that means I'll have more information and docs up there eventually.

 

Anyway, as always, some photos:

 

 

mk2-k_hires_03.jpg

mk2-k_hires_01.jpg

mk2-k_hires_02.jpg

Edited by matthew180
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