> Nice design - should be handy for giant RAM on small MCUs. That's kinda the whole point ;-)
> It's interesting to compare the S3A with older parts. Nice that it can > get by without the 2.5V VCCAUX It does need a separate 1.2v VCCcore though. > I'm a bit curious what happens if you forget to set the 3.3V > configuration bit - does it damage the part? I hope I never find out ;-) > Xilinx docs have all sorts of dire warnings about proper decoupling of > the various supplies. I put a bunch of caps on the back of the board, but I also suspect it's CYA. > For FPGA configuration I used slave serial mode and drove the DIN/CCLK > direct from a SPI port on my MCU - saved having to use Xilinx's special > configuration flash parts. Does mean that the start-up process is a bit > more complex though. I thought of doing that, but the advantage of using a separate eeprom is that I can use the mcu to download the bitstream to it faster than I can reprogram the MCU to have a built-in bitstream. Plus I can learn something new in the process ;-) I also thought about adding a serial port, ethernet chip, and sdcard slot to the test board, but then I decided "one step at a time". If I were using a 32 bit mcu I'd reconsider - big RAM is a key to uclinux support. The m32c is only a 16 bit MCU. Maybe I'll add them anyway, though, just for fun. _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
