hamster 46 Report post Posted January 29, 2012 Hi, I was having all sorts of random bad pixels in my frame buffer. Some build would be fine, others would have a lot of bad pixels. Turns out that some of my signals weren't being packed into the I/O buffers, and were being fed from FPGA fabric. Turning on "Pack I/O Registers/Latches into IOBs" in the mapping properties fixed this. Hope it helps somebody! Mike Share this post Link to post Share on other sites
alvieboy 24 Report post Posted January 31, 2012 Two comments: Comment One: Yes, always pack outputs on IOB. But make sure all outputs are synchronous. Comment Two: I don't, cause I can't That kills my timing for the PPS stuff [every output is a huge muxer], so only core things [like VGA, SPI flash] are packed. Also, if you are reading from IOB make sure you properly sample your stuff and avoid metastability (add a latch+FF or two FF). Will delay signal, but signal will come out clean. And Comment Three: You made it again to Hack-a-Day, congratulations http://http://hackaday.com/2012/01/31/fractal-viewer-can-zoom-and-enhance-like-on-csi/ Share this post Link to post Share on other sites
Jack Gassett 0 Report post Posted February 6, 2012 Yes, congrats on the HaD posting. Jack. Share this post Link to post Share on other sites
hamster 46 Report post Posted February 7, 2012 I'm going to try for another... I got my FPGA board transmitting morse code 'SOS' on 25MHz with no added hardware, just a few lengths of wire. Share this post Link to post Share on other sites
Jack Gassett 0 Report post Posted February 7, 2012 Sounds cool! Share this post Link to post Share on other sites
Guest monkeydoo Report post Posted April 12, 2012 I'm going to try for another... I got my FPGA board transmitting morse code 'SOS' on 25MHz with no added hardware, just a few lengths of wire. Cool. Now the killjoy part. In realitity the output will be spectrally horrible. Consider at the very least a low pass to attenuate all those nasty harmonics. You will be " spewing " garbage all over the spectrum I know people who communicate all over the world with little more than a crystal oscillator and a length of wire ! Share this post Link to post Share on other sites
