User Guide

4
1 – Functionality
Write Depth/Width and Read Depth/Width
The depth range for each port is 1-99999. The width range for each port is 1-999.
The two ports can be independently configured for any depth and width. (Write Depth * Write Width)
must equal (Read Depth * Read Width).
Single Clock (CLK) or Independent Write and Read Clocks
(WCLOCK, RCLOCK)
The FIFO Controller without Memory offers a dual- or single-clock design. The dual clock design allows
independent read and write clock domains. Operations in the read domain are synchronous to the read
clock, and operations in the write domain are synchronous to the write clock.
Selecting the single clock option results in a much simpler, smaller and faster design.
The default configuration for FIFO Controller without Memory is a Single clock (CLK) to drive WCLOCK
and RCLOCK with the same clock. Uncheck the Single clock checkbox to drive independent clocks (one
each for Write and Read).
Clock Polarity - Click the up or down arrows to change the active edge of your Write and Read clocks. If
you use a single clock you can select on only CLK; if you use independent clocks you can select the
polarity of both the WCLOCK and RCLOCK.
Write Enable (WE)
WE controls when the write data is written to the Write Address (MEMWADDR) of the RAM at the clock
edge.
WE Polarity - Click the up or down arrows to change the active edge of WE signal.
Read Enable (RE)
Asserting the RE causes the RAM data at the read address (MEMRADDR) location to be read out.
RE Polarity - Click the up or down arrows to change the active edge of RE signal.
Allow Write when FIFO is Full
Select this checkbox to enable the FIFO to continue write when it is full. Your existing FIFO value will be
overwritten.
Allow read when FIFO is Empty
Select this checkbox to enable the FIFO to continue to read when it is empty.
Asynchronous Reset (RESET)
Asserting the active-low RESET signal resets the FIFO Controller without Memory.
RESET Polarity - Click the up or down arrows to change the active edge of RESET signal.