Altera Integer Arithmetic IP Manuale Utente Scaricare il pdf (Pagina 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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Altera Integer Arithmetic IP Manuale Utente Pagina 100