User guide

230 www.xilinx.com System Generator for DSP User Guide
UG640 (v 12.2) July 23, 2010
Chapter 3: Using Hardware Co-Simulation
other System Generator blocks use. When a value is written to one of the block's input
ports, the block sends the corresponding data to the appropriate location in hardware.
Similarly, the block retrieves data from hardware when there is an event on an output port.
Hardware co-simulation blocks may be driven by Xilinx fixed-point signal types, Simulink
fixed-point signal types, or Simulink doubles. Output ports assume a signal type that is
appropriate for the block they drive. If an output port connects to a System Generator
block, the output port produces a Xilinx fixed-point signal. Alternatively, the port
produces a Simulink data type when the port drives a Simulink block directly.
Note:
When Simulink data types are used as the block signal type, quantization of the input data is
handled by rounding, and overflow is handled by saturation.
Like other System Generator blocks, hardware co-simulation blocks provide parameter
dialog boxes that allow them to be configured with different settings. The parameters that
a hardware co-simulation block provides depend on the FPGA board the block is
implemented for (i.e., different FPGA boards provide their own customized hardware co-
simulation blocks).