Altera Integer Arithmetic IP - Manual (Page 100)

Parameter Name Type Required Description
COEF1_[]
Integer No Specifies the coefficient value
[0..7]
for the inputs of the
second multiplier. The
number of coefficient bits
must be set similar to the
value of
WIDTH_COEF
.
COEF2_[]
Integer No Specifies the coefficient value
[0..7]
for the inputs of the
third multiplier. The number
of coefficient bits must be set
similar to the value of
WIDTH_
COEF
.
COEF3_[]
Integer No Specifies the coefficient value
[0..7]
for the inputs of the
fourth multiplier. The
number of coefficient bits
must be set similar to the
value of
WIDTH_COEF
.
Design Example: Shift Accumulator
A multiplier-accumulator can be used to implement FIR filters. This design example uses the
ALTMULT_ACCUM megafunction to implement a serial FIR filter, in which both the data and
coefficient are shifted serially into the multiplier and then summed in the accumulator. This example uses
the MegaWizard Plug-In Manager in the Quartus II software.
The following design files can be found in
altmult_accum_DesignExample.zip :
serial_fir.qar (archived Quartus II design files)
altmult_accum_ex_msim (ModelSim-Altera files)
Understanding the Simulation Results
The following settings are observed in this example:
• The
dataa[]
and
datab[]
input widths are both set to 16 bits
• The output port,
result[]
is set to a width of 33 bits
• The
accum_sload
input is enabled
The following figure shows the expected simulation results in the ModelSim-Altera software.
UG-01063
2014.12.19
Design Example: Shift Accumulator 8-19
ALTMULT_ACCUM (Multiply-Accumulate) Altera Corporation
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