feeding a FIFO from PCI
in [Linux Hardware]
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From: Nial Stewart on 14 Apr 2008 06:06 John, I might have missed something, but if you need a FIFO size of 8K x 48Bits you'll get that into most reasonable sixed FPGAs these days (Cyclones or Spartans). Otherwise hang a DRAM off it as rickman says. If your data rate to the FPGA is only 1MByte/second you could almost get away with one of the FTDI USB 1.1 interfaces (FT245R gives an 8 bit fifo output). If this isn't sufficient there are a couple of easy to implement microcontrollers about that give you a FIFO interface at USB 2.0 full speed data rates. The host PC would need to do more of the work but if this is acceptable then an embedded SBC seems like complete overkill? Nial.
From: Didi on 14 Apr 2008 08:10 Nial Stewart wrote: > ... > If your data rate to the FPGA is only 1MByte/second you could almost get > away with one of the FTDI USB 1.1 interfaces (FT245R gives an 8 bit > fifo output). If the data rate is only a 1-2 Mbytes/S it can be done in a single MPC5200, with some (64M, 128M?) DDRAM and a flash chip. The FIFOs are on chip, one of the serial ports can be set to do 16 or 32 MbpS; it will only have to be deserialized - some CPLD or whatever (6 x 74hct164....?). The entire BOM would be $50 to $100 for prototype quantities. With DPS running on it, net access over the 100 Mbps Ethernet port is there. Want a HDD, connect one to the 5200 ATA port. But this is me, the rest of the world seems to consider designs which do not rely on some intel/linux/MS monstrosity illegal nowadays. Dimiter P.S. a similar (doing apr. 1.8 Mbytes/S thing) is at http://tgi-sci.com/y2demo/ ------------------------------------------------------ Dimiter Popoff Transgalactic Instruments http://www.tgi-sci.com ------------------------------------------------------ http://www.flickr.com/photos/didi_tgi/sets/72157600228621276/ Original message: http://groups.google.com/group/comp.arch.embedded/msg/f06c1735c181b6cb?dmode=source
From: Joel Koltner on 14 Apr 2008 12:20 "Didi" <dp(a)tgi-sci.com> wrote in message news:e7faffe3-e733-4033-aa1a-abb07d42f36e(a)q10g2000prf.googlegroups.com... > But this is me, the rest of the world seems to consider designs which > do not rely on some intel/linux/MS monstrosity illegal nowadays. It's just that finding people to code on those platforms is easier and -- if you need the complexity of a GUI or full TCP/IP stack or USB host anyway, there's a huge amount of code, completely free, that you can leverage if you just "tow the company line" and use one of those "monostrosities." A couple bucks extra in hardware is a lot easier to get funded than a few more programmers and another year of development time, after all (especially when finding GOOD programmers is somewhat tricky these days!) I bet plenty of people ask why your software doesn't "look" like standard Windows, don't they?
From: Didi on 14 Apr 2008 13:07 Joel Koltner wrote: > "Didi" <dp(a)tgi-sci.com> wrote in message > ... > > But this is me, the rest of the world seems to consider designs which > > do not rely on some intel/linux/MS monstrosity illegal nowadays. > > It's just that finding people to code on those platforms is easier and -- if > you need the complexity of a GUI or full TCP/IP stack > .... you get that under DPS as well - with a lot of functionality as a bonus and with a few uS worstcase IRQ latency (try *that* on the wintel things). More, it fits it in a fraction of the flash space the wintelinux alternatives take. > I bet plenty of people ask why your software doesn't "look" like standard > Windows, don't they? Actually they typically think this is windows runing underneath on the first sight... As for programmers interfacing to this or that system the overhead is negligible if you will use DPS. For this particular application - moving data from a tcp connection into some fifoed hardware - the job to do on behalf of DPS can be explained in a message shorther than this one. So it is all about plain human nature - practiclly all people I know are too scared to make a step aside of the known path, it takes some threat to their existance to venture that. It does not matter how tempting those nice things under that tree look, danger may be lurking around if the place is so desolated.... :-). Dimiter ------------------------------------------------------ Dimiter Popoff Transgalactic Instruments http://www.tgi-sci.com ------------------------------------------------------ http://www.flickr.com/photos/didi_tgi/sets/72157600228621276/ Original message: http://groups.google.com/group/comp.arch.embedded/msg/0a16cc12dffb1ba5?dmode=source
From: Joel Koltner on 14 Apr 2008 13:24
"Didi" <dp(a)tgi-sci.com> wrote in message news:fd9dc69f-eb74-45d8-820e-5d75b59b9a8e(a)p25g2000pri.googlegroups.com... > you get that under DPS as well - with a lot of functionality as a > bonus and > with a few uS worstcase IRQ latency (try *that* on the wintel things). Sure, it's just that for anyone with DPS experience (where's their web site, btw?) you'll probably find at least 100 people with Windows or Linux experience. > Actually they typically think this is windows runing underneath on the > first > sight... My first guess would have been DOS with an extender. :-) > So it is all about plain human nature - practiclly all people I know > are > too scared to make a step aside of the known path, it takes some > threat to their existance to venture that. With most people, yes, this is absolutely true. Businesses as an entity are the same way -- they'll keep using crappy tools that are well-known to them because the thought of changing to something else just looks too risky... and no one wants to be the fall guy if it turns out their evaluation of the alternatives were wrong. ---Joel |