Introduction to DSP48E and DSP48E1 Slices

Note This help file is not intended to be a comprehensive discussion of DSP48E or DSP48E1 slices. Before using these functions, We recommend that you become familiar with the Virtex-5 FPGA XtremeDSP Design Considerations User Guide for DSP48E functions or the Virtex-6 FPGA DSP48E1 Slice User Guide for DSP48E1 functions. These guides are available on the Xilinx Web site at www.xilinx.com and contain detailed information about the slices, including architectural details, timing considerations, descriptions of input and output ports, and sample applications that will help you program the slices effectively.

A DSP48E slice is a digital signal processing logic element included on certain FPGA device families, such as the Xilinx Virtex-5. You can use this slice to perform different kinds of arithmetic operations, including a multiply-accumulator, multiply-adder, and a one- or n-step counter. You also can use the slice to perform different kinds of logic operations, such as AND, OR, and XOR. You can cascade multiple DSP48E slices to implement more complex functions, including complex multipliers and n-tap finite impulse response (FIR) filters, without using any additional FPGA fabric resources.

A DSP48E1 slice is a digital signal processing element available only on certain Xilinx Virtex-6 and newer FPGA device families. The DSP48E1 slice includes a pre-adder before the multiplier and other features that extend the functionality of a DSP48E slice. This pre-adder is useful in implementing certain algorithms, such as symmetric FIR filters. Page 11 of the Virtex-6 FPGA DSP48E1 Slice User Guide contains a comprehensive listing of enhancements.

To access a DSP48E slice, add a DSP48E function to the block diagram and then configure the function.