A1000 or A500 Back plane

[trekiej]

Has anyone considered building a back plane to place a modified Minimig design on it?

I believe it could hold about 3 high density FPGA chips.
The A1000 has a board that is piggy backed and uses a set of header pins. I believe.
The FPGA would be soldered onto a board with pin holes around the perimeter.

Good day.

[trekiej]

Considering how many pins are on some FPGA chips,  making a daughter card similar to Minimig that would have pins around the perimeter may be useful.  It may solve for a while the multilayer board making approach.  

The older computers like the Altair 8800 had a back plane that connected the processor board to memory,video, etc.
Those board where at 90 degrees to the back plane. These would be parallel to fit into amiga cases.
I do not know what would be needed on the back plane to support the daughter cards.  I guess it would be up to the designer.
Making one to fit into old Amigas would be interesting.

[trekiej]

Smoking?
How about a ham for Christmas?
lol

How does this sound?
To make a poor man's 4 layer board, use 2 two layer boards.
I do not know yet what to use to insulate the two layers.
The bottom layer could have the mounting holes drilled out larger to allow the board to set lower in the case over the standoffs.  Your project may not need this.
This of course does not have to be an Amiga project.
This maybe nothing new in the circuit board industry.

 

[trekiej]

I am not for sure how 2 two-layer boards would become a 3 layer board.  Does one of the copper layers get removed completely during processing?  The mylar I believe could insulate the two copper layers.  I am not saying this is the best way.  I agree it would be thick.

I wish I had acces to .030 inch 2 layer boards.  I feel I would have to make them myself.

[trekiej]

I have found 2 companies so far that sell 1/32 and 1/64 inch single and double sided pc boards.

Has anyone on this thread used Eagle Cad?
Is there a program that you prefer?

Good day.