Read pages 1-4 of this article http://www.analog.com/media/en/training-seminars/tutorials/MT-085.pdf for information DDS.
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import magma as m
m.set_mantle_target("ice40")
from loam.boards.icestick import IceStick
N = 8
icestick = IceStick()
# TODO: configure parts (Clock and GPIO)
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main = icestick.main()
# TODO: Define main
m.EndDefine()
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m.compile('build/dds', main)
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%%bash
cd build
cat sin.pcf
yosys -q -p 'synth_ice40 -top main -blif dds.blif' dds.v
arachne-pnr -q -d 1k -o dds.txt -p dds.pcf dds.blif
icepack dds.txt dds.bin
iceprog dds.bin
Wire up the GPIO pins to a logic analyzer to verify that the circuit produces the correct waveform.
You can use Saleae's export data feature to output a csv file. Replace our example data in data/dds-capture.csv to plot the results.
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import csv
import magma as m
with open("data/dds-capture.csv") as sine_capture_csv:
csv_reader = csv.reader(sine_capture_csv)
next(csv_reader, None) # skip the headers
rows = [row for row in csv_reader]
timestamps = [float(row[0]) for row in rows]
values = [m.bitutils.seq2int(tuple(int(x) for x in row[1:])) for row in rows]
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import matplotlib.pyplot as plt
%matplotlib inline
plt.plot(timestamps[:100], values[:100], "b.")
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