Xilinx vs Altera

PFC · 2008-06-04T20:11:05+00:00

Sorry about the title, everyone put down the flamethrowers, lol. I have a few questions about Xilinx and Altera (actually Spartan-3E versus Cyclone III) which relate to a particular project, so here are the specifics. Currently the prototype system is on a Spartan-3E 500 to validate the design, and it works. This was for development, though, as for the final version a larger FPGA is needed ; the 500E is starting to feel a bit tight.This FPGA system has : - Microblaze with caches (small caches) - 16 bit SDRAM with mch_opb_sdram controller (without OPB actually) - CPU connected to RAM through the MCH/XCL - Ethernet LAN9117 MAC+PHY, with DMA to SDRAM via MCH/XCL - IO peripheral, with DMA to SDRAM via MCH/XCL - And lots of IOs (well not so many on PQ208 but final version will have a larger FPGA).Here is what it does : - Receives data from PC over ethernet in UDP packets - Buffer in SDRAM - Output data in user's format of choice on the pins - Read data from pins - Buffer - Send back to PC in UDP packets A simple protocol (not finished) will handle UDP retransmissions etc a-la-TCP but with very low latency. Primary purpose is to transfer multichannel audio (up to about 8-9 megabytes/s) but also digital scope (sample, buffer, send to PC) and other data acquisition applications. It will also need to do some DSP work on the audio (resampling, dithering, and some complicated filtering, etc) and possibly DSP on the acquired signals in a DAQ scenario. Now. Three problems. Everything is good with Xilinx except the DSP part, I guess the logic would fit in a Spartan-E3 1200 with lots of room to spare except I might be short on multipliers. Now that would be a problem to realize that once the final board is made ! So I thought about Spartan-3A DSP but it has a packaging problem : 0.8mm BGA ! No way. 1mm is fine but not 0.8mm. Second problem, this SDRAM is really crummy and so is mch_opb_sdram. Granted, I get 90 MB/s from a 16 bit SDRAM running at 50 MHz which is ...

Xilinx vs Altera

Jun 04, 2008 23 Replies

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Jim Granville 18 years ago

The Atmel AP7 is an AVR32 core, not Cortex M3, but they do have low cost development boards for this, and it has plenty of horsepower.

-jg

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PFC 18 years ago

r. =

Yeah I thought about using this one, too. I have a board with this CPU here (the NGW100) but was not impressed by= =

the ethernet performance. It is probably the Linux overhead, though. If = my =

plans for firewire fail due to licensing I will consider it again ;)

en =

Actually I wonder why no-one proposes such a board at a decent price. =

There are some that come close, but there is always a gotcha, either =

price, or some other problems like in this one :

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Where the connection between the CPU and FPGA is using a crummy 8 bit b= us =

and the the FPGA hasn't got enough IO pins exposed...

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PFC 18 years ago

Actually there is this nice board :

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Still a bit expensive, though (about ?450 with the 1600E and the CPU)

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Nico Coesel 18 years ago

Why FIR? AFAIK it takes less logic to implement an IIR filter.

Programmeren in Almere? E-mail naar nico@nctdevpuntnl (punt=.)

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