Hi, tried running Flickernoise on the Xilinx ML401 yesterday. Surprisingly, the "gradual crash" problem is still present - which supports the theory of the RTL bug.
So my general guidelines for the RC2 boards would simply be to use one via per power pin on the FPGA and multiple vias for each big decoupling capacitor (as Xilinx recommends) and better decoupling close to the DRAM (to reduce the power supply noise which is a bit high). Even if this didn't apparently cause real problems on the prototypes, I think it is better to make the design more resistant. The ML401 backport is here (essentially with new memory map and USB): http://github.com/lekernel/milkymist-ml401 The USB ports are routed to the expansion connectors (see the UCF file and ML401 schematics). A makeshift USB transceiver can be improvised by simply putting 68 ohm resistors in series on D+/D- and using 3.3V I/O on the FPGA (set the jumper under the board) - this was good enough to get my mouse working. S. _______________________________________________ http://lists.milkymist.org/listinfo.cgi/devel-milkymist.org IRC: #milkym...@freenode Webchat: www.milkymist.org/irc.html Wiki: www.milkymist.org/wiki
