On Sunday 04 January 2009, Jon Elson wrote: >Gene Heskett wrote: >> On Sunday 04 January 2009, Peter C. Wallace wrote: >>> On the other hand you can do a lot with a embedded 32 bit processor in a >>> FPGA (the ZPU for example uses about 20% of a 400K SP3, runs at ~ 100 >>> MHz, is BSD licensed and has a GCC toolchain) >> >> Which again, sounds like a plus till you said 100mhz. That might do for >> servo driven machines but I'd guess it won't run steppers at usable speeds >> will it? > >Well, if you are embedding in an FPGA, then it costs NOTHING to add in a >hardware step rate generator! >That's the whole BEAUTY of putting it all in an FPGA, if there's an >important function the CPU can't satisfy, add additional hardware to do it.
It also means a familiarity with FPGA compilers, something I have no clue about. And at my years, no real incentive. I probably won't last long enough to put it to use. >But, EMC is very tied to doing everything in floating point, and the >FPGA CPU IP's generally don't have this. Most FPGAs that are not >designed from the ground up for DSP don't have the dedicated multiplier >logic to do well at this, either. If you want to do things with FPGAs, >it turns out that the smaller devices are QUITE reasonable in cost, but >the larger ones become very expensive. There are some really incredible >Xilinx chips out there in their Virtex series, but they cost $7800! Can >you imagine a single CHIP for that price? (Now, I'm not saying you need >one of these to put a CPU in, but you could easily be talking about a >$200+ chip for this. A $20 Arm9 starts looking a lot more affordable then.) I had wondered about that too. Does that arm9 have an fpu? And if it does, is it wide enough for emc? Thanks, Jon -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Think twice before speaking, but don't say "think think click click". ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
