Re: [Discuss-gnuradio] Re: interfacing a DSP array card to USRP2

[Matt Ettus]

On 04/12/2010 05:22 PM, Vikram Ragukumar wrote:
> Matt,
>
> In our effort to distill the gemac core and related logic, we have
> pulled out the following module under u2_core
> SERDES, Dsp core, UART, external RAM interface and the buffer pool
>
> > The mac is all contained in simple_gemac, and above that in
> > simple_gemac_wrapper:
> > which is instantiated in u2_core. Most of the buffering happens in
> > simple_gemac_wrapper in the fifo_2clock_cascade files.
>
> (a) Is any buffering for the gemac done using buffers in the buffer pool
> or is it ok to eliminate that module all together ?

Yes, it does buffering.  You can get rid of it, but then you'll need to 
create a module which holds the FIFO contents until there is a complete 
packet.  Otherwise, the ethernet will start sending the packet before 
you have a complete packet there.

> (b) The synthesis report currently shows that 24 BRAM's are being used
> by the design. Does this sound about right ? Are there modules unrelated
> to gemac or aeMB that we can pull out, to reduce BRAM usage ?

You're going to need to do your own exploration.  ISE has a feature to 
tell you which modules are using block rams.

Matt