Python code for 8 order FIR configuration

axi_fir8_coeff.py

from pynq import Overlay
import numpy as np
from scipy import signal
import matplotlib.pyplot as plt
from pynq import MMIO

# Configure the overlay
overlay = Overlay("ultra96_bd_fir.bit")

# Define the IP addresses and definition
IP_BASE_ADDRESS = 0x00B0000000
IP_HIGH_ADDRESS = 0x00B0000FFF
ADDRESS_RANGE = IP_HIGH_ADDRESS-IP_BASE_ADDRESS+1
fir8 = MMIO(IP_BASE_ADDRESS, ADDRESS_RANGE)

# FIR filter design
nTaps = 8; # FIR filter 8th order

fs = 10e3/2 # This value is corresponding with the Nyquist frequency
fc = 3000
wc = fc/fs
taps = signal.firwin(nTaps, wc)
w,h = signal.freqz(taps)
plt.plot(w, 20 * np.log10(abs(h)), 'b')

# Filter quantification
nBits = 32
tapsQ = []
for i in taps:
    tapsQ.append(np.int(i*2**(nBits-1)))

# Write filter coefficients on IP
coeffIndex = 0
for j in tapsQ:
    fir8.write(coeffIndex,j)
    coeffIndex = coeffIndex+4