Revisions explained
Date: Monday, October 29 2018 @ 18:41:30 UTC
Topic: Amiga FPGA accelerator

As every project progress it is normal to have revisions. Same story goes for Vampire card accelerators. From minor fixes no one will really notice to more serious ones who enabled higher performance using same hardware parts. There were lot of various forum posts where skilled people commented design of the cards and proposed better solutions in certain areas. We started to investigate those claims and noticed that some of them were valid. This was huge boost for us from Amiga community and sign that we can do even better. PCBA factory also asked for some changes to speedup assembly process. Since Vampire 500 and Vampire 600 are very similar cards in process of designing and production what's proven to be good for one was later on implemented on other model. You may find this article very confusing but only in case that you didn't follow progress of this project closely for past several years.

Card model PCB layers PCB color Power fix Digital Video Out fix Other remarks
VAMPIRE 500 V2 4 Green/Black NO NO Development version of the card, not for sale
VAMPIRE 500 V2+ Rev:2 4 Black NO NO Added I/O expansion header, new logo
VAMPIRE 500 V2+ Rev:2.1 4 Black Quck fix*** Quck fix*** Added strip bars on 2 sides with fiducials for professional PCBA
VAMPIRE 500 V2+ Rev:2.2 4 Black YES YES I/O expansion header replaced with Ethernet module connector. Implemented all improvements from Vampire 600 V2 Rev: 2.1 and 2.2
VAMPIRE 600 V2 Rev:2 4 Green NO NO First version of the card with 2 SDRAM chips
VAMPIRE 600 V2 Rev:2.1 4 Black YES YES Added bottom GND layer, introduced via stitching and teardrops, added fiducials and PCB panelization
VAMPIRE 600 V2 Rev:2.2 4 Black YES YES Added top GND layer


VAMPIRE 500 V2+ Rev: 2 and 2.1

VAMPIRE 500 V2+ Rev: 2.2


VAMPIRE 600 V2 Rev: 2.1 and 2.2

Before we start I need to point out that first series of Vampire cards build by me or 3rd parties need those fixes. Everything build after 2016. have those fixes included or cards were replaced by never models. By reading incomplete manuals from Alpha & Omega Semiconductor about AOZ1021A I have used as a power solution for Vampire cards I made mistake by not putting enough capacitors after inductor. As a result card was unstable on newest cores who are more and more power hungry. Even now reading datasheet for that part I see that this part is not recommended for new designs. But let's be honest, this was due to my inexperience. Later on I found out that others who used same parts in their projects made same mistakes as I did.To fix this problem you only need to add 2 capacitors in parallel to C3 and C6. That's exactly how users fixed their old cards from Silver core days and made them work on Gold versions of Apollo cores. In reality this is very simple fix but it could be ugly and sending cards like this to end users would give picture about unfinished product. Interesting thing is that someone might need this fix and someone don't. So if your card does not work properly with one of the Apollo Gold cores this is the first step.

Vampire 600 V2 card without power fix
Vampire 600 V2 card with power fix I did initially on my card. Ceramic capacitors C3 and C6 each valued 10uF before replaced with 4 22uF capacitors.

Power fix with 220uF electrolytic capacitors placed in parallel with 10uF capacitors C3 and C6. Maybe better solution for this specific card because weaker inductors used. Unlike ceramic capacitors electrolytic capacitors are polarity sensitive so closely observe pictures.


There was much better solution I did in final production. Solution was very slick and did the job perfectly. C3 and C6 capacitors were replaced with 22uF values, but real fix happened on bottom side of the card replacing 0805 100nF ceramic capacitors with 22uF 0805 ones. This ensured more power to the FPGA and real professional production could start.

Vampire 500 V2+ Rev:2.1 card with power fix

One step further was taken with Vampire 600 V2 Rev: 2.1 with adding two more capacitors near C3 and C6 valued 22uF. Some minor fixes regarding bottom side were taken. This made no difference but it looked more professional.


As for Digital Video out initially we used 0603 270Ohm resistors in series. This wasn't best solution for everyone depending on TV/monitor type used. Sometimes on higher resolutions picture was unstable.

On Vampire 500 V2+ Rev:2.1 resistors were replaced with 0603 100nF capacitors leaving Silkscreen showing R marks.

Later in Vampire 600 V2 Rev: 2.1 this was done properly and R was changed to C as it should be.


Having retro computer and not having soldering station near is not an option anymore. Simple fixes on main or additional hardware is something that become normal. After all without various people writing on forums how did they improve their hardware who knows will those things will be ever discovered. This was definitive prove that we are going in right direction with this project because community showed interest. Most of the people wouldn't notice mentioned differences in models or their flaws but I needed to point to them to clear my mind. You see, I am strange person who is prepared to sit for hours designing some card just to be able to move one trace 0.1mm to make it aligned with all the others same time moving 100 traces or components to make more room. I m well aware that this is not important and that no one will be able to see that. But, I will know, don't know how to explain... Yes, I know that I have problem of some kind. Now, right question is, am I able to make perfect design, in the terms how I see it. No, even now, when I got latest Rev: 2.2 I noticed some things that could be even better.
Well, how about others, big companies. Recently I have purchased lot of hardware for modern computers and decided to take a look. How about that you need to remove graphic card from new MSI Arctic motherboard to be able to remove battery. They had loads of options to place battery on some other place and yet they didn't see this as a problem. That's not just one mechanical issue, you can spot lot of them just briefly looking into motherboard. How about mentioned graphic card and tutorial on MSI website how to make it work properly. Seeing all of that I can only say that we are more than good with our mistakes. So let's look forward to next revision who will be perfect finally. HMmMm maybe not :)

This article comes from Amiga FPGA Accelerators

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