A flexible Digital Signal Processor module includes a Filter unit comprising a multiplier and an adder, where the multiplier receives input from a memory and a Shift Register Lookup table. The Digital Signal Processor module may implement digital filters such as FIR or IIR filters by providing suitable filter coefficients from the memory and data values from the Shift Register Lookup table. An optional state machine may ensure synchronisation of addressing of the memory Shift Register Lookup table, and between multiple instances of the Digital Signal Processor module where these are required for a particular filter implementation. The proposed architecture offers additional modes of operation wherein operations other than filter implementations are supported.