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Correct Pin 3 output to scale to the reduced comparator size.

This commit is contained in:
Stephen Olesen 2015-07-02 19:57:32 -06:00
parent 6ff2791963
commit 77a8c62b78
1 changed files with 3 additions and 3 deletions
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6
DDS.cpp
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@ -140,13 +140,13 @@ uint8_t DDS::getDutyCycle() {
uint8_t phAng;
#endif
phAng = (accumulator >> ACCUMULATOR_BIT_SHIFT);
int8_t position = pgm_read_byte_near(ddsSineTable + phAng)>>(8-COMPARATOR_BITS);
int8_t position = pgm_read_byte_near(ddsSineTable + phAng); //>>(8-COMPARATOR_BITS);
// Apply scaling and return
int16_t scaled = position;
// output = ((duty * amplitude) / 256) + 128
// This keeps amplitudes centered around 50% duty
scaled *= amplitude;
scaled >>= 8;
scaled += 128;
scaled >>= 8+(8-COMPARATOR_BITS);
scaled += 128>>(8-COMPARATOR_BITS);
return scaled;
}