Just finished building Ralle Palaveev A2VGA v1.6

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Just finished building Ralle Palaveev A2VGA v1.6

I just finished these...

 

 

This version pretty much has everything inlcuding POP9 (Power Over Pin 9) and A2USB Mouse support built in.

 

My only complaint is the seeming obsession to make cards as small as possible.  It would be a lot nicer to build these if the card was made a little bigger so that all the components fit without having to be tipped up.  Normal 1/4 watt resistors and the most common types of Schottky diodes don't fit neatly in this layout.  I don't normally buy 1/8 watt resistors because they just aren't as easy to find in bulk at reasonable prices.  Frankly at least at JLCPCB which is where I normally order boards, making this thing a little bigger wouldn't increase the price by more than a couple dollars at worst.  I also don't see any real reason to not just make cards rectangular becaause it doesn't seem to save any money to remove material.  But those are minor complaints really.

 

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If you are standing them up,

If you are standing them up, perhaps you should put them in a zig-zag arrangement. One guy on the Bulgarian retro-forum managed to fit 1W resistors on the Vince Briel card this way:

 

 

I am just not sure if picking up noise doesn't start to become an issue at this point, since the VGA signal is analog.

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I'm not sure if the leads are

I'm not sure if the leads are enough longer just from standing them up to make a big difference as far as noise goes.  I've never had any problems with earlier versions of this card where I had them stood up like that.  With 1/4 watt they fit.  With full watt resistors they are fat enough you might have to alternate them like that to make them fit.

 

 

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It's a standard DIN0204 package

 

 

You really don't need 1/8W resistors to fit a standard DIN0204 3.6mm spacing. Yaego CFR25S series 1/4W resistors work just fine.

For the diode, try a DO-34 package like a BAT85.

 

I spoke to Ralle about this. The board size was decreased to allow the use of a greater number of PCB manufacturers that provide low cost prototyping services for boards under 100x100mm. 

 

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It's probably unlikely I will

It's probably unlikely I will be making any more of these cards since I now have a bunch.

 

Those size resistors are not the commonly available ones.  I'd have to special order them rather than just use what I normally keep stocked.

 

I have only ever used JLCPCB and PCBWay, they offer reasonable price on boards even up to the max size possible for an Apple II or IBM PC/XT card, so that doesn't make a big difference to me.  The PCB itself is not usually that pig a portion of the overall cost of the board.  In this case other components are the bigger part.  Saving a few pennies on the board is going to be partially offset anyway if you have to pay more for special order resistors and diodes.

 

But it is his project and he can do it how he wants.

 

 

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I don’t think he is trying to

I don’t think he is trying to reduce the size of the card in order to save pennies. It’s more of a personal vision of what is a good PCB design. Some people perceive it to be able to fit everything in the smallest area possible.

 

I personally like to concentrate on symmetry, things lining up and hiding all the vias and as many of the traces as possible on the front side by placing them under the components. This way the card ends up looking very beautiful, IMHO. Also I would never place a chip upside down and have its electrons fall out, as EEVblog's David Jones likes to say.

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I guess maybe my priorities

I guess maybe my priorities are different.  Placing components further apart makes building the boards a lot easier.  When everything is crammed into place it is more difficult, especially for people with large hands like I have to build the cards.  Also as I said, fitting the most popular sizes of components where that matters like resistors and capacitors just makes sourcing the parts easier.  And not requiring tilting of resistors or diodes is nice.  I guess maybe that all boils down to selfish laziness.

 

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You should let him know - I

You should let him know - I am sure he will be open to some constructive criticism. After all he is just doing this for fun like the rest of us. From what I have gathered, Dr. Ralle Palaveev is actually an MD specializing in gastroenterology.

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VGA

Nice I have received mine's from JLCPCB

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Why did Ralle delete the

Why did Ralle delete the entire 1.6 directory off his github with no notes or documentation stating why? Was the circuit faulty?

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I don't know.  I have 3 of

I don't know.  I have 3 of the 1.6 cards working as Mouse cards, but two seem to have issues. I still haven't had time to analyse things furhter.

 

 

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The circuit is not faulty
Verault wrote:

Why did Ralle delete the entire 1.6 directory off his github with no notes or documentation stating why? Was the circuit faulty?

In my conversations with Ralle, he prefers to move the functionality added in version 1.6 to a different project he is working on. The circuit is not faulty, but the PCB layout could use a few tweaks. I'm using portions of that design (with his permission) as reference for a different card i'm building.

 

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chrisa850 wrote:Verault wrote
chrisa850 wrote:
Verault wrote:

Why did Ralle delete the entire 1.6 directory off his github with no notes or documentation stating why? Was the circuit faulty?

In my conversations with Ralle, he prefers to move the functionality added in version 1.6 to a different project he is working on. The circuit is not faulty, but the PCB layout could use a few tweaks. I'm u

I was hoping he was just making a little more room for resistors etc., but either way, we appreciate the information! 

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Looks like he has made a

Looks like he has made a SmartPort Pico card as well. I saw it appear on the Bulgarian "craigslist" yesterday:

https://bazar.bg/obiava-44138298/hdd-emulator-za-apple2-pravets-8h-32mb-s-microsd-karta

 

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CVT wrote:Looks like he has
CVT wrote:

Looks like he has made a SmartPort Pico card as well. I saw it appear on the Bulgarian "craigslist" yesterday:

https://bazar.bg/obiava-44138298/hdd-emulator-za-apple2-pravets-8h-32mb-s-microsd-karta

 

[[{"fid":"38688","view_mode":"default","fields":{"format":"default","al

 

Very nice.  I wish it was all through hole parts so it was more home builder friendly.

 

Looks like this one does not include a PLD.  I wonder how it works.

 

 

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softwarejanitor wrote:I wish
softwarejanitor wrote:
I wish it was all through hole parts so it was more home builder friendly

 

There is also a through hole variant of the same design (currently being tested). Wait for it...

Yes, the new design has no PLD. It doesn't need it, since it acts as a "normal I/O card" only: it only emulates read/write operations on the $Cxxx address range. Hence, it doesn't have to monitor the full address bus, so enough PICO I/O pins were available without using the PLD. Advantage is, it's cheaper, and the behaviour is fully software defined (no need to reprogram a PLD). Disadvantage is, it doesn't have access to the full address space, so it couldn't do what the A2VGA card's are doing (e.g. also monitor the video RAM area or the whole address space). However, it can do whatever other "normal" Apple II I/O cards could do.

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That I/O card design opens up

That I/O card design opens up a ton of possibilities.  I will really be looking forward to seeing the design of it both the PCB and software.

 

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I was thinking it would be

I was thinking it would be pretty cool to have an "experimenters" version of this card made as a full size card with all the unused pins from the Pico broken out onto headers and the remainder of the card space made as a proto board.  That would really be handy for people when they were working up new Pico based cards.  They could even use one of the breadboards that has an adhesive back and stick it onto the open part of the card for easier prototyping.

 

Here's an example of a proto board with a breadboard stock onto it with the adhesive back.

 

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