Hi all We've set up a simple FIFO on a Spartan3 FPGA using the free code from Xilinx XApp258 (FifoCTLR_IC_V2.vhd) Initially this mechanism was tied to a DMA and we were having a hard time figuring out what was going on. By process of elimination, we tied the FIFO to an address and used the read/write strobed to read and write to the fifo.
We can scribble data and read it back. The weird thing we're seeing is that the "empty" does not become true until data is read for the first time. It also becomes untrue with data left in the FIFO (usually 2 longs remaining).
Has anyone seen this before? Or do we need to pay for the libary to get it fixed :)
TIA Remco