Interesting thread, too bad it's not tagged properly. ----- Original Message ----- From: "Herbert Graf" To: "Microcontroller discussion list - Public." Sent: Friday, March 10, 2006 3:37 PM Subject: Re: high datarate controllers > On Fri, 2006-03-10 at 14:19 -0800, uncutno wrote: >> Ok, last question + thank you wery much for all the help! >> >> If the FPGA got 10k gates, it is better to have a separate RAM circuit >> since i will need maybe 32kb of ram? Or should i go for a bigger FPGA? > > Hmm, well, that again depends on what you want. > > External RAM is a good idea if changing the amount of ram is important, > if RAM speed isn't that important, or if sticking with a standardized > type of RAM is important (i.e. using DDR SODIMMs from the notebook > world). > > OTOH using the internal RAM of the FPGA is generally much less error > prone since you just instantiate the RAM primitive and use it (vs. > bringing all the pins to top level, connecting them correctly to the > parts, and then hoping the external RAM parts don't dissapear 5 minutes > after you fab the board!). Generally using the internal memory in an > FPGA has minimal impact on both the logic capacity of the FPGA and the > speed you can run it at. > > For a modest amount like 32kbits I would personally stick with the > FPGA's internal memory (Xilinx terminology is "block rams", I don't know > what Altera calls them). The EP1K50 has ~40kbits, aside from being a > slightly larger package (144-TQFP) it is basically the same as the > EP1K10 you were looking at before. > > Note also the EP1K10 in the 100-TQFP package only has 66 IOs. External > memory is very good at sucking up huge amounts of IO depending on what > you choose, so even if you go with an external memory you may have to > upsize to the 144-TQFP anyways! :) > > TTYL > > ----------------------------- > Herbert's PIC Stuff: > http://repatch.dyndns.org:8383/pic_stuff/ > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist