10.1.15.4 FIR Filter Implementation Rules/Timing Diagrams

The following tables list the parameter rules and implementation parameters for an FIR Filter.

Table 10-64. FIR Filter Parameter Rules
Family Variation Parameter Rules
All FIR2 PREC ≥ O_WIDTH
SX and SX-A All O_WIDTH ≤ 32
SX and SX-A All TAPS ≤ 32
Table 10-65. FIR Filter Implementation Parameters
Parameter Value Description
LPMTYPE LPM_FIR FIR-filter category
LPM_HINT FIR1 Basic options
FIR2 Advanced options

Internal Precision (PREC) specifies the minimum number of bits:

  • For the time tab registers
  • From multiplier outputs kept for further processing
  • From adder outputs kept for further processing

Currently, the RTL-model does not reflect the PREC parameter, so there may be differences between the simulated output of the structural netlist and the RTL-model for the low-order bits.

Table 10-66. Internal Precision (PREC)
Variation Value Description
Basic Options 97, 0 Maximum output resolution, same as O_WIDTH
Advanced Options PREC See parameter rules