SID-Maths: Frequency: ---------- To calculate the frequency corresponding to the 16-bit value in $D400+$D401, $D407+$D408, $D40E+$D40F use the following formula: Freq = 16Bit-Value * Phi2 / 16777216 Hz where Phi2 is the system-clock, 985248 Hz for PAL-systems, 1022727 Hz for NTSC-systems. A good approximation for both systems is the formula: Freq = 16Bit-Value / 17.03 Pulse-Width: ------------ To calculate the pulse width (in %) corresponding to the 12-bit value in $D402+$D403, $D409+$D40A, $D410+$D411 use the following formula: PulseWidth = (16Bit-Value / 40.96) % |