Pre-production Part 1:

A project log for 'Flea Ohm' FPGA Project

My attempt at making an FPGA experimenters board in a popular form factor :)

Valentin AngelovskiValentin Angelovski 04/11/2017 at 08:265 Comments

Hello again! :-)

Quick update on my Ohm project: Prototype testing is now almost complete. Only thing not tested to date was the CSI header, thanks to a silly error that slipped under the radar..

Based on these tests (among other things) I've updated my PCB design to include all fixes and/or tweaks arising from it:

One of the things that really bothered me was the lack of user GPIO breakout. So I increased the GPIO count to 55 user pins total, thanks to the inclusion of a 20-pin 'GPIO-B' header, as well as increasing the pin-count of the 'GPIO-C' header :-D

There were also other changes and tweaks as well - I will write a more comprehensive list of the changes when I have more free time.

Next step: Review the above as soon as possible and see if I can knock one up quickly.. ;-) Thanks for reading!


Marq Watkin wrote 04/24/2017 at 07:11 point

I noticed on this board, pin 1 and 2 are at the other end of the board compared the pi-zero sized version (and rasp pi boards). Is this intentional?

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Valentin Angelovski wrote 04/24/2017 at 08:40 point

Completely intentional. I have 180-degree rotated the 'GPIO-A' header on Ohm MkII in a manner found on the Orange Pi One boards. This decision was made mainly due to physical clearance issues brought about by the presence of the Ethernet and stacked USB host ports. This means that any installed rpi hats will point away from, rather than sit directly on top of, Flea Ohm MkII.

Rotating the main GPIO header makes more sense (IMHO) when you consider the extra 26 GPIO available on the other two auxiliary headers on my board. Cheers.

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Marq Watkin wrote 04/24/2017 at 10:01 point

Makes sense. Thanks for the reply

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elpekos wrote 04/22/2017 at 09:42 point


Project is going on... nice. Do you plan to release your Verilog sources, they would be helpful to interface this board in my project ?


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Valentin Angelovski wrote 04/24/2017 at 04:28 point

Well, my VHDL knowledge has always been far better than Verilog (and this is reflected in the HDL examples I've created for my older boards). However, some projects that were previously ported (and released) to my older FleaFPGA boards (like Nicolae's Next186 project) were written in Verilog. 

I've tried hard to like Verilog (and thus improved my knowledge of it a bit over time) but I still keep coming back to VHDL. With that said however, I will see what I can do to bring more Verilog examples for Flea Ohm. :-)

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