[sdiy] FPGAs

[Matthew Smith]

Quoth Jason Tribbeck at 28/01/11 19:02...
...
> Xilinx does a Linux version (there's also the free version - the WebPack 
> version [FWICR]). However, I think it's reasonably strict on what 
> versions of Linux it runs on.

Thanks, Jason - I'll double-check before I go and take 3.8Gb out of my 
monthly data allocation! I seem to recall seeing something about the 
RedHat and SuSE commercial distros being supported, but I *think* that 
CentOS is supposed to be 100% RHEL compatible. And I believe it's on my 
ISP's mirror, so I can download it without penalties :-) Can run that as 
a VM.

> The IDE supports VHDL, Verilog and schematic entry.
Cool, so on a par with the Altera offering then.

> Xilinx's own programmer is quite expensive (well, the USB2 version), but 
> there are some that work with the IDE (Digilent make one), and there are 
> schematics available for a parallel port programmer.
People still have parallel ports - wow? ;-) I've got USB to serial modules
floating round my desk, so I'm sure that I should be able to cobble
something, ditto for the Altera - it's all just JTAG isn't it, and 
that's just a serial thing?

> 100, 144 and 208 pin QFPs are available for some of the Spartan 3 series 
> (3, 3A, 3E) - the 3A is the easiest to work with insofaras it only 
> requires two supplies (rather than three for the 3/3E). 
Ooh, nasty - didn't realise these things needed multiple supplies.

> You will need a 
> configuration memory device if you want it to remember what it's doing 
> (although the automotive 3A version doesn't require this from memory).
Do you mean that they lost STATE when powered down, or is the actual 
gate configuration held externally? If they require external memory just 
to work, that would be a total blocker from my point of view - certainly 
wouldn't drag me away from microcontroller/discrete logic hybrids.

> For later series than Spartan 3, it's pretty much all BGA, I'm afraid.
What this world needs is a socket for BGAs like you get for PLCCs.

> If you're after a DIL version, then there are companies which sell FPGAs 
> on a DIL board - mainly for supporting legacy CPUs (6502 springs to 
> mind). I've only looked at the ones based on Xilinx, but I would imagine 
> there are some for other platforms. Some of these have embedded 
> SDRAM/DDR, and some have 5V converters.
I was really only joking when I mentioned DIL - I'm OK with SMD and will 
often design with it just to avoid drilling holes - it's just finer 
pitch stuff that starts to spook me. Soldering more than 150 half 
millimeter pins sounds worse than a trip to the dentist.

Cheers

M

-- 
Matthew Smith
Smiffytech - Technology Consulting & Web Application Development
Business:      http://www.smiffytech.com/
Blog/personal: http://www.smiffysplace.com/
LinkedIn:      http://www.linkedin.com/in/smiffy
Skype:         msmiffy
Twitter:       @smiffy