[Fpga-synth] Altera Cyclone II Starter Board ?

[Eric Brombaugh]

Scott Gravenhorst wrote:
> http://www.altera.com/products/devkits/altera/kit-cyc2-2C20N.html
> 
> Has anyone messed with this?

No, but it looks like a good deal for $150.

> I like the audio connectors and the inclusion of both SDRAM (8 Mbyte) and
> SRAM (64 Kbyte), but I have no idea how nasty the pin sharing is.

Schematic PDF is available from that web page. Pin sharing doesn't seem 
too awful - looks like most pins are dedicated to just one function.

> I'd also
> have preferred at least twice that amount of SRAM.  It looks like the FPGA
> internal RAM is smaller than the Xilinx XC3S500E, but it has 26 18x18
> dedicated multipliers vs. XC3S500E which has 20 (with shared routes to
> block RAM).  Even though the "equivalent gate" bogus count is about twice
> the Xilinx part, it appears to me that the Xilinx part has about the same
> capacity.

You could try grabbing their free development software Quartus and 
running one of your designs through it to see how well it fits into that 
device. Compare total utilization between the Xilinx and Altera parts 
for the ultimate ground-truth.

> The Cyc-II multiplier arrangement is interesting, but I've not yet needed a
> 9x9 multiplier - however, I'm also not a 10 year design veteran either. 
> The one time I needed a small multiplier it was to multiply a varying value
> by a constant and it was easy to build that out of a few adders.

I've not worked with Altera Cyclone architecture personally, but some of 
my colleagues at a former employer ("The worlds largest semiconductor 
maker") thought very highly of it. You can do some nice things with 
their DSP blocks.

> Also, what do they mean by 24 bit resolution coder-decoder ?  It doesn't
> say _DAC_ per se and "24 bit resolution" looks suspicious of something
> other than a real 24 bit DAC to me.

http://www.wolfsonmicro.com/products/WM8731/

Basically means that the digital I/O path supports 24-bit resolution. 
The SNR looks more like a 15-bit converter though. Just your basic 
stereo audio codec - nothing special. I've interfaced similar parts to 
my S3Esk for just a few $$. I2S driver logic is pretty simple.

> It _looks_ like the board price is $150, so it's comparable to the S-3Esk,
> unless there's extra stuff you have to buy to make it work as an audio
> development board.  It also appears as if the dev software comes included
> with the board.

It appears like that's all you need. The download cable is built in just 
like the S3Esk - good thing since it's fairly expensive stand-alone. 
Quartus is OK - I've used it for some of their CPLDs and it worked fine. 
No idea how well it works on the higher-density devices, although the 
rate of complaints on comp.arch.fpga for ISE and Quartus looks about the 
same.

Eric