User guide

104 www.xilinx.com System Generator for DSP User Guide
UG640 (v 12.2) July 23, 2010
Chapter 1: Hardware Design Using System Generator
DSP48 Macro 2.0-Based Signed 35x35 Multiplier
The same model shown above can be migrated to the new DSP48 Macro 2.0 block. The
following simple steps and design guidelines are required when updating the design.
1. Make sure that input and output pipeline register selections between the old and the
new block are the same. You can do this by examining and comparing the Pipeline
Options settings.
2. If there is more than one unique input operand required, you must provide MUX
circuits as shown in the fugure below.
3. Ensure that the new design provides the same functionality correctness and quality of
results compared to the old version. This can be accomplished by performing a quick
Simulink simulation and implementing the design.
4. When configuring and specifying a pre-adder mode using the DSP48 Macro 2.0 block
in System Generator, certain design parameters such as data width input operands are
device dependent. Refer to the LogiCORE IP DSP48 Macro v2.0 Product Specification
for details on all the parameters on this LogicCore IP.