I've recently received the
BeMicro CV FPGA dev board, and it's a cute little bugger. I love it and I'm super pleased with my purchase, but it's got an 80-pin card-edge connector, and I can't seem to find the right one. In a
post I wrote for my blog, I noted that the suggested mate is a
Samtec MEC-140-02-L-D-RA1. The photos show a plastic divider, but no such corresponding cutout exists on the card edge! I've counted pins and it doesn't appear that it would even fit half the connector or something like that. Does anyone have any suggestions on how to make use of it (without soldering because I try to reuse all my parts)?
Also, I'm pretty new to serious electronics, but I'm a very experienced programmer (though new to Verilog). I've played with 100-in-one kits early on, but my enthusiasm was damped by spring terminals as a kid, so I invested heavily in the programming side of my skillset. Since my buddy gave me a breadboard, it's been a whole different experience.
I've got a little Hello World demo going on the board (also run the Propeller P8X32A on it!!) showing a few logic gates, but there's a quirk. In the sim, the code acts as you would expect (an AND gate acts like an AND, OR like OR, XOR like XOR), but on the board, an AND acts like an OR, an OR like an AND, and an XOR like an XNOR! The code in my post is written so that it'll light up the LEDs in the "intuitively correct" fashion (to my mind at least).
A good friend of mine who's an actual EE explained that I could use a chunk of the logic elements to swap things around, but I'd like to know: what's the standard practice for dealing with this sort of mirrored logic? (It's not really an inverse to my mind as a programmer, because you can't just negate the gate or the inputs as the truth tables for AND and OR aren't symmetrical.)
Ultimately, I plan on implementing my own small processor inside it (to tackle a specific crypto problem I have in mind), but I'd love any advice or corrections to the information contained in my post.
Thanks everyone! (And especially thank you Dave for teaching me so much about electronics!)