IO (SOUND LIST) PAGE I6
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FREQUENCY CONTROL (for generators 0, 1, 2)
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Two bytes must be transmitted to the SGC for a given register
and to compute the number of counts from the frequency F
use: N = 111860 / F
Binary 1-REG#-N(1s 4 bits)-00-N(ms 6 bits)
Note that N must be split up into its least
significant 4 bits and most significant 6
bits (10 bits total).
The lowest frequency possible is 110 Hz and the highest is
55938 Hz.
NOISE CONTROL |
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One byte must be transmitted to the SGC:
Binary 1-1-1-0-0-T-S
T = 0 for white noise, 1 for periodic noise;
S = Shift rate (0,1,2,3) = frequency center of noise.
S=3=frequency dependent on the frequency of tone
generator #3.