Altera SCFIFO User Manual
Page 8
Parameter
Type
Requir
ed
Description
delay_rdusedw
(5)
delay_wrusedw
(5)
String
No
Specify the number of register stages that you want to
internally add to the
rdusedw
or
wrusedw
port using
the respective parameter.
The default value of
1
adds a single register stage to the
output to improve its performance. Increasing the value
of the parameter does not increase the maximum
system speed. It only adds additional latency to the
respective output port.
add_usedw_msb_bit
String
No
Increases the width of the
rdusedw
and
wrusedw
ports
by one bit. By increasing the width, it prevents the
FIFO IP core from rolling over to zero when it is full.
The values are ON or OFF. If omitted, the default value
is OFF.
This parameter is only applicable for Stratix and
Cyclone series (except for Stratix, Stratix GX, and
Cyclone devices).
rdsync_delaypipe
(5)
wrsync_delaypipe
(5)
Integer
No
Specify the number of synchronization stages in the
cross clock domain. The value of the
rdsync_
delaypipe
parameter relates the synchronization
stages from the write control logic to the read control
logic; the
wrsync_delaypipe
parameter relates the
synchronization stages from the read control logic to
the write control logic. Use these parameters to set the
number of synchronization stages if the clocks are not
synchronized, and set the
clocks_are_synchronized
parameter to FALSE.
The actual synchronization stage implemented relates
variously to the parameter value assigned, depends on
the target device.
For Cyclone II and Stratix II devices and later, the
values of these parameters are internally reduced by
two. Thus, the default value of 3 for these parameters
corresponds to a single synchronization stage; a value
of 4 results in two synchronization stages, and so on.
For these devices, choose at least 4 (two synchroniza‐
tion stages) for metastability protection.
use_eab
String
No
Specifies whether or not the FIFO IP core is
constructed using the RAM blocks. The values are ON
or OFF.
Setting this parameter value to OFF yields the FIFO IP
core implemented in logic elements regardless of the
type of the TriMatrix memory block type assigned to
the
ram_block_type
parameter.
8
SCFIFO and DCFIFO Parameters
UG-MFNALT_FIFO
2014.12.17
Altera Corporation
SCFIFO and DCFIFO IP Cores User Guide