EP2S90F1020C5 Datasheet, PDF (546/768 Pages) Altera Corporation – Stratix II Device Handbook, Volume 1

Operational Modes
FIR Filter
The four-multiplier adder mode can be used to implement FIR filter and
complex FIR filter applications. To do this, the DSP block is set up in a
four-multiplier adder mode with one set of input registers configured as
shift registers using the dedicated shift register chain. The set of input
registers configured as shift registers will contain the input data while the
inputs configured as regular inputs will hold the filter coefficients.
Figure 6–14 shows the DSP block configured in the four-multiplier adder
mode using input shift registers.
6–30
Stratix II Device Handbook, Volume 2
Altera Corporation
January 2008