Mostek MK50240N

[Theo]

I gave the top octave thing a go on the AVR today.
The idea to use the timer for the 12 root division proved rather messy.

Instead I used R0 to R15 as 8 bit down counters and wrote a loop that always
takes 76 cycles to complete.
Every time a register is zero the corresponding output is toggled, this
results in 12 freq outputs with 50% duty cycle.
Using the divider numbers 253 ,239, 226, 213,..., 142, 134 gave 785.5 Hz
 nearly a G ) as the highest note on a 16Mhz device.
(((16000000 / 76) / 134) / 2 ) = 785.5
Fine tuning or pitch modulation can be done by changing the uC clock.
Hardly a "top" octave generator though :(


If I had to do this for real, I'd use a FPGA.
Twelve 10 bit counters with 12 comparators.
Comparator resets the counter and toggles a flip-flop.
That all.

Cheers,
Theo

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