Memory width on Spartan-3 boards

Simon · 2004-07-18T10:58:42+00:00

So, I have a 32-bit processor design which I'd like to move to the implementation stage, and I was wondering which of the currently-available boards have 32-bit wide memory... I don't really fancy designing my own because I've never ventured near 4-layer boards, and if I was making my own, I'd want one of the FG456 packages, and presumably you'd have to get that professionally soldered anyway...As far as I can tell: Xilinx starter kit ------------------ Pros: 32-bit wide RAM LCD/Leds for debugging PS2/VGA outputs Price: $99 :-) Cons: Only 1 MByte of RAM Uses the '200 part not the '400 No ethernet PHY Fixed oscillator freq. (the CPU goes faster :-) Not many user-IO's available AVnet Spartan-3 evaluation kit ------------------------------ Pros: '400 part used :-) Two oscillators, socketed Lots of IO's available Ethernet, VGA, PS2, RS232, Leds etc. Could potentially be a PCI card Cons: Only 1 MByte RAM Not clear if the memory is 32-bit wide Price is $399 Memec DS-KIT-3SLC400-PAC ------------------------ Cons: Has no memory on-board, enough said. Nu Horizons Spartan3 board -------------------------- Pros: Uses the '400 part, but only in the '208 package Has D2A and A2D onboard Has Flash RAM Has LCD (4x24) as well as leds,buttons etc. Has spare oscillator socket for > 20MHz operation Price - $164 :-) Cons: SDRAM appears to be 16-bit wide Only has ~20 user io due to '208 packageSo, nothing is perfect [grin], The AVNet one may be the best of the bunch, despite being the most expensive, so long as it has 32-bit wide RAM. I'd really appreciate it if someone who already has the board could tell me :-)For the record (in case any board companies are listening :-) my ideal board would be something like: - FG456...

Jul 18, 2004 21 Replies

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Yes, but I have *plans* [grin] The idea is to use the burst-mode of the DDR2 SDRAM to fill a line of i/d cache at once, taking a hit on fetching the first entry in the line, but hopefully winning overall. For that to work though, I want the access to RAM to be as fast as possible. It would of course work with 2x16-bit access, but I want speed :-)

I've more or less decided to go for the BroadDown2 board - I think the possibilities for adding stuff onto it are better, and I want SDI in and analog-video --> video decoder chip (Phillips SAA7115 probably). I want to put an MPEG2 decoder / encoder (one at a time) onto the FPGA as well as the CPU core for general purpose stuff. It's going to need an SDRAM controller, and probably a PCI interface too... Like I said, plans :-)

So, I'm looking really at the 1.5M part rather than the 400k part, which means lots of expense (Foundation, aaarrggghhh), and I'm going to try and get as much done *before* I cough up the cash to decide if I can actually *do* it or not...

As for motive, well at the moment it's purely curiosity on my part, but if it all pans out well, there is a commercial possibility (I work in the professional post-production industry, and there is a gap I could fill...)

Simon.