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Altera_Forum
Honored Contributor
17 years agordreq didnt read all the data in dcFIFO (functional simulation)
hi,
i have question regarding to rdreq in DCFIFO. i'm writing 4 16-bits data into dcFIFO at 100Mhz speed. and read at 200Mhz speed. the problem now is, rdreq didnt read all 4 data in FIFO. only 3 available(data2,data3 and data4 only). data 1 is missing. i run for functional simulation only. could someone help me on this? i'm stuck almost 1 day already. DCFIFO setting and simulation output attached. Thanks -Farhan5 Replies
- Altera_Forum
Honored Contributor
can someone help me on this?
Thanks a lot! - Altera_Forum
Honored Contributor
ok.noted.
now, i have another issue when combining my sub blocks (datapath + CU). when i simulated the datapath block separately, data is read out nicely in 4 clock cycles at every rising edge during rdreq is HIGH. but, now, when i tested in combined block with CU, it's failed. FYI, rdreq(read_fifo) is not controlled by CU. i control it manually. this CU is responsible for write operation(which is successful simulated). rdreq depends on "Routerclk" and writereq(write_fifo) depends on "clk". i attached the simulation for combined design + FBD + successful simulation for Non combined design. As u can see in the encapunitsimulation picture, the data is written to FIFO(during write_fifo is HIGH). FOUR 16-bit data is written to FIFO(i put the number in pink color). but, when rdreq is HIGH(read_fifo is HIGH), it's missed the last data, which is 0000000000000000. encapunitsimulation2 shows weird counting of the data in fifo. i want the data to be read out as in simulationnoncombined picture. (functional test simulation). Please help. Thanks Guru.. - Altera_Forum
Honored Contributor
wrfull looks high on that first write. There is circuitry on by default that disables extra writes/reads when full or empty, as that can completely corrupt the fifo.
- Altera_Forum
Honored Contributor
Note that at beginning wrfull pin is high, so, first write attempt is ignored.
- Altera_Forum
Honored Contributor
can someone help me? :(