35 lines
881 B
Python
35 lines
881 B
Python
#!/usr/bin/python3
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#
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# Make a table of Mockingboard wavelength values (high and low bytes)
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# Corresponding to the frequency values used in BBC Micro
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# SOUND statements.
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#
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d7 = 2349.32 # D7 is pitch value 253
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clk = 63780.27 # AY-3 clock (1.023MHz / 16)
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freqs = [0] * 256
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divider = [0] * 256
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freqs[253] = d7
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for i in range(254,256):
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freqs[i] = freqs[i-1] * (2 ** (1 / 48))
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for i in range(252,-1,-1):
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freqs[i] = freqs[i+1] / (2 ** (1 / 48))
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for i in range(0,256):
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divider[i] = int(round(clk / freqs[i]))
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coarse = int(divider[i] / 256)
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fine = int(divider[i] % 256)
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# print("{:3d}: {:9.3f} {:5d} ({:2d} {:3d})".format(i, freqs[i], divider[i], coarse, fine))
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print("\nMFREQHIGH");
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for i in range(0,256):
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print(" DB >{:.0f}".format(divider[i]))
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print("\nMFREQLOW");
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for i in range(0,256):
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print(" DB <{:.0f}".format(divider[i]))
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