erros in Simulation of FIFOs in Modelsim

[mu]

Hello,

we use vivado 2019.1 and  modelsim SE-64 2019.2 to simulate fifo ip,

but data from fifo is 'xxx'

fifo ip is fifo_generator_v13_2_4;

why? how to fix? 

thank you!

[bruce_karaffa]

Is the reset to your FIFO active low?  Are you showing it on your screenshot?  Is the FIFO reset before writing to it?

[dpaul24]

@mu ,

As mentioned above please show the FIFO signals explicitly in another screenshot post.

Remember that you should read the FIFO only when it has valid data. Monitor the fifo_empty signal and the write_data_count. You should go on reading as long as write_data_count > 1 and the fifo_empty  is low. Else stop reading and wait till sufficient data is available again for reading.

why? how to fix?

I guess the problem is related to how you are controlling the write and read data to and from the FIFO. Please recheck the logic. Without looking in to your control logic RTL, I can't say more.

[mu]

please check the screenshot

[mu]

the fifo is reset before writing.

[bruce_karaffa]

One more time.  Which signal is the reset to the FIFO?  Is the reset active high or active low?

[drjohnsmith]

why is the valid going "unknown" 

[mu]

thank you very much for your reply!

we have fixed it

there are errors in RTL

[mu]

there are errors in RTL

thank you!