Question: What is the maximum order of the FIR filter that I can implement with the PSoC 3/5's Digital Filter Block (DFB)?
Answer: Digital Filter Block of PSoC 3/5 supports 128 locations to store coefficients, and so it can directly implement up to 128 tap FIR filter (127th order FIR filter). The DFB provides 1 tap per cycle performance for 24-bit computation.
It is possible to implement higher order filters by having system software move sets of sample/coefficient data in/out of the DFB Data RAMs in blocks. But the maximum data rate will be reduced due to the overhead of software to service the DFB, and also because the DFB must stall while the System software reads/writes the Data RAMs.
