hi laura, there are a couple of standard ways people stream data to the PPC and out over the network:
ping pong memories ----------------------------- the FGPA write to memory A and then sets a flag saying memory A is full. the PPC code waits for this flag to be set and then moves memory A to the ethernet port. the PPC resets the flag, telling the FPGA that memory A is empty. as soon as the FPGA fills memory A, it starts filling memory B, and then sets a flag B. when the PPC sees flag B is set, it moves memomy B to the ethernet port and resets flag B.... FIFO ------- the FPGA writes data continuously into a FIFO PPC code the PPC waits for the FIFO empty flag. if the FIFO is not empty, the PPC reads a word from the FIFO and sends it to the ethernet port then it waits for the FIFO empty flag again.... we probably have some examples of these codes... best wishes, dan On Wed, Mar 14, 2012 at 2:45 PM, Laura Vertatschitsch <[email protected]>wrote: > Hey Andrew, > > Thanks for the reply - we are looking forward to the ROACH 2 in the future. > > I haven't been able to open all of the tutorials, but I have seen a few. > So I apologize if I may have missed something obvious, and I would even > really appreciate an answer that says "hey you, go read about this." I see > that data can be saved using a snap block, and I could save a concatenated > set of samples as a single 64 bit integer, and I can save a maximum of 2^16 > of these. Is there a better way of using the roach memory to guarantee > that I can read and save all of the data continuously? I'm wondering if > there is perhaps a way of constantly reading from a snap register fast > enough to insure that we have captured the data continuously and saved it > to our external computer. > > --Laura > > > On Mon, Mar 12, 2012 at 11:59 PM, Andrew Martens <[email protected]> wrote: > >> Hi Laura >> >> The ROACH does not have a direct 1Ge connection to the FPGA, any data >> must exit via the PPC if it is not going through the 10Ge links. >> >> The ROACH2 however, has a 1Ge link directly to the FPGA. The yellow >> block has been completed and has been designed to act the same as the >> 10Ge links (basically the same interface, can be accessed from the PPC >> if needed, ARP table managed from PPC etc) except that the data rate is >> lower (8 bit data paths instead of 64 bit). >> >> We should be finalising these yellow blocks and making an announcement >> soon so that people who are interested can start designing for ROACH2. >> >> Regards >> Andrew >> >> On Mon, 2012-03-12 at 17:22 -0700, Laura Vertatschitsch wrote: >> > Hey Casperites, >> > >> > I see a lot of data about reliable streaming using the 10GbE ports and >> > a lovely simulink block to boot. Is there an analogous method for >> > streaming data out over the 1Gbps ethernet? >> > >> > Not sure if someone has written some python control scripts to >> > accomplish this - I may have just missed it on the wiki. We would >> > love to stream 10MHz time-domain data off our board. >> > >> > --Laura >> >> >> >
