1. Home
  2. Field-Programmable Gate Arrays
  3. MPMC2 : npi issues #2

MPMC2 : npi issues #2

This is a follow-up from my previous discussion. ivo, "MPMC2 : npi issues" #, 31 Aug 2006 1:44 am

I am now able to get addrAck back from the MPMC2, but it seems like the FIFO never dumps data to the DDR. After a number of acks (depending on the size of the FIFO) followed by WrFIFO_push the FIFO_almostfull signal is asserted and no more acks are received. The FIFO_almostfull signal never goes low again.

Someone have an idea what is wrong ? I assume that my npi never gets prioritized by the arbiter, but my arbiter algorithm is quite simple(round robin). The PPC which is also attached onto the MPMC2 works as expected.

Reply to
ivo
Loading thread data ...

Hi,

Have you looked at the release notes for the MPMC2 core? There are a few known issues there, which might be related to your problem, and which unfortunately I don't fully understand...

I am myself debugging a read cycle and having problems as well. I tried 4 and 8-word reads and in both cases the last double-word never shows up on the PI_RdFIFO_Data bus. When I do a few read cycles in sequence, the result is even more confusing: some data is lost, some is late, etc... I haven't tried the latest MPMC2 release (8/31) yet, but I don't have much hope, as it doesn't seem from the release notes that they did any related changes...

/Mikhail

#, 31 Aug 2006 1:44 am

FIFO never dumps data to the DDR. After a number of acks (depending on the size of the FIFO) followed by WrFIFO_push the FIFO_almostfull signal is asserted and no more acks are received. The FIFO_almostfull signal never goes low again.

prioritized by the arbiter, but my arbiter algorithm is quite simple(round robin). The PPC which is also attached onto the MPMC2 works as expected.

Reply to
MM

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.