[sdiy] Top Octave Generator (was Chinese MG-1s??!?)

[Tom Wiltshire]

On 30 Apr 2008, at 22:08, Veronica Merryfield wrote:

>
> On 30-Apr-08, at 10:57 AM, Eric Brombaugh wrote:
>> Veronica Merryfield wrote:
>>
>>> The way to make this work is not to have 12 dividers but to use a  
>>> rolling scheduler.
>>
>> Very nice approach.
>>
>>> A little intelligence will be needed to handle events that come  
>>> close together.
>>
>> You said a mouthful there. Traversing the queue to schedule the  
>> next instance of the current edge, then fetching the top of the  
>> queue to set the timer for the next event is probably going to eat  
>> up enough time to make event crowding a very real issue. A fun  
>> problem for someone. :)
> Since the event set is limited, or perhaps I should say very well  
> defined, and although I know there will be occasions where thing  
> will get congested, I think it would work, The queue is a simpler  
> problem than most queues, again it is limited and well defined, and  
> I think there are a number of optimization opportunities.
>
> Also, the description queue here does not mean a linked list. For  
> instance, if the event structures had an extra field that is a next  
> index, the events could be an array of structures and a single  
> 'next_index' variable. The rejigging of the queue is about changing  
> the times, the next index fields and the next_index. At the times  
> where it gets congested, the event edges might be off by a few  
> clocks but that should be no real issue and could add to the  
> character or effect :) If you wanted to ensure the errors didn't  
> accumulate, you can correct for delayed events, again, that happens  
> in ECUs.

I generated a list of the events to have a look at. Makes quite  
interesting reading. There are quite a few occasions when things do  
get quite thick, but often you've got 20 or 30 cycles between events  
at least.

http://www.electricdruid.com/TopOctave.html

I haven't started thinking of an algorithm to work out which bit  
changes next, but maybe you don't need one, since there's only 5820  
events.

Anyone still tempted?

Regards,
Tom