Vampire 600 PCB-dimensions
Date: Tuesday, March 05 2013 @ 16:01:27 UTC
Topic: Amiga FPGA accelerator
It is quite easy to design new piece of hardware regarding dimensions but when you need to design PCB to fit into another piece of hardware you may encounter to number of problems. No matter how much you measure final PCB can give you much headaches when you need to create some simple things like holes, sockets etc... Maybe simplest solution for amateur developer is to measure everything using some measurement tool and according to gathered values design virtual PCB, print it on paper in scale 1:1 and then see if everything fits. Take your time because it is easier to print 10 different versions of PCB on paper than to build PCB to find out that you missed something.
How it is done on Vampire 600 PCB? It was complicated because I had to understand space between PLCC-68 socket and 4 holes on Amiga 600 motherboard. Because if you move, for example, PLCC-68 socket just for 1mm you will end up with major problems regarding dimensions between that socket and 4 holes. So since I didn't find any information's regarding this problem on the internet I decided to publish here how it's done and maybe someone will find it useful. I think that in the process of creating open sourced design is essential to pay attention to every detail. So first I used PLCC-68 socket and fit it on top of the MC68K CPU on Amiga motherboard. Then I used red pencil and marked center point of socket. From that center point I measured distance to every hole on Amiga motherboard used for fitting accelerator board. For that purpose I used caliper to get accurate dimensions. After that, in CAD software (in my case Altium designer) I created PCB with 100mmx100mm dimensions and added components and holes at exact locations to support dimension relationship between
PLCC-68 socket and 4 holes mentioned earlier. Then all I needed to do is to print it on paper and see if everything fits. On printed paper I drilled holes in 5 places, center of PLCC-68 socket and on 4 holes. After that by simply placing paper on PLCC-68 socket and finding red colored center point viable try the hole was something I needed to see are the other 4 holes are in correct places so they can be used to assemble Vampire 600 PCB to Amiga motherboard.