Altera SCFIFO Bedienungsanleitung PDF herunterladen (Seite 25)

Table 15: Completion of Data Transfer from ROM to DCFIFO Waveform Description

State Description

WRITE When the write controller is in the WRITE state, and rom_addr = ff, the write controller

drives the fifo_wrreq signal to high to request for last write operation to DCFIFO. The

data 100 is the last data stored in the ROM to be written into the DCFIFO. In the next

rising clock edge, the write controller transitions to the DONE state.

DONE In the DONE state, the write controller drives the fifo_wrreq signal to low.

-- The fifo_wrfull signal is deasserted because the read controller in the receiving domain

continuously performs the read operation. However, the fifo_wrfull signal is only

deasserted sometime after the read request from the receiving domain. This is due to the

latency in the DCFIFO (rdreq signal to wrfull signal).

Figure 11: Completion of Data Transfer from DCFIFO to RAM

The fifo_rdempty signal is asserted to indicate that the DCFIFO is empty. The read controller drives the

fifo_rdreq signal to low, and enables the write of the last data 100 at ram_addr =ff. The word_count

signal is increased to 256 (in decimal) to indicate that all the 256 words of data from the ROM are success‐

fully transferred to the RAM.

The last data written into the RAM is shown at the q output.

Note:

To verify the results, compare the q outputs with the data in rom_initdata.hex file provided in the

design example. Open the file in the Quartus II software and select the word size as 32 bit. The q

output must display the same data as in the file.

Related Information

DCFIFO Design Example

Provides all the design files including the testbench. The zip file also includes the .do script

(dcfifo_de_top.do) that automates functional simulation that you can use to run the simulation using the

ModelSim-Altera software

UG-MFNALT_FIFO

2014.12.17

Design Example

SCFIFO and DCFIFO IP Cores User Guide

Altera Corporation

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Altera SCFIFO Bedienungsanleitung Seite 25