[sdiy] topoctave generator

[Theo]

How about 8054 timers as TOG.
Each 8054 holds 3 16bit timers so 4 of those are needed for an octave.
You would need a uC to set the division factors, allowing all kind of
scales.
And the clock inputs could be used for easy fine tuning.

BTW you want the uC anyway for midi input,
and a truck load cmos switches as key contacts ;)

One problem though, I don't know if the 8054 is still available.
It comes from times when even the 7to11 sold TOG ICs.

Another keen and cunning plan,
The same as above, but using 12 (or 6) Atiny AVRs (8 pin DIL).
Small PICs would do too.
Each uC programmed as 16bit divider(s) IC and driven from a central clock.
With clock I mean a master-tuning clock, _not_ the uC clock.

Wait even better, same scenario but with twelve 90S1200 AVRs.
Each uC generating a pitch and performing the octave divisions.

Lets see, 15 I/O pins:
One for the master tuning clock input and 10 for the octave outputs.
Leaves 4 inputs for things like scale selection and dutycycle select
e.g. 50% for organ, 25% for strings or 0% for saw-waves.
(set the uC output as OC and give a short pulse to discharge a cap,
recharge the cap with a fixed resistor to VCC = saw)

Or when 5 or 6 octaves are enough you may have multiple outputs for each
octave.
For example, one set of outputs gives 50% dutycycle pulse
and another set outputs give short pulses for the saw wave trick.

Mmm, a only 12 ICs for a multiple waveform main oscillator.
Well probably a few more, for the master clock and some opamps as
buffers and comparators (saw+comparator = pwm)
Sounds good to me :)

Theo