[sdiy] Sequencer with Selectable Number of Stages - schematic?

[Brock Russell]

Selecting the number of stages you want is as simple as taking the 
output after the one you want and connecting it to the first 4017 
reset. Notice that you don't get 10 usable outputs per stage with the 
AND gate cascade technique because one output is always active on 
these parts so you get nine outputs from the first stage and eight 
from each cascaded stage.

Brock

At 12:00 PM 10/9/2007, John Mahoney wrote:
>At 01:22 PM 10/9/2007, DAF wrote:
>
>>Hello - I am looking for info on making a sequencer with a 
>>selectable number of stages.  I was thinking something based on 
>>cascaded 4017's.  I have the app note from ON Semi showing how to 
>>cascade 4017's for more stages using AND gates, but how would I go 
>>about selecting anything from, say, 2 to 30 stages, assuming 
>>cascaded 4017's?  Is it as simple as taking the reset pin of the 
>>first 4017 and connecting it to whatever stage you want to be the 
>>last, or do you have to connect it to the one after that?
>
>No, it's not quite as simple as that. From what you are describing 
>it sounds like the cascaded unit will be clocked only once every per 
>loop (8 or 10 steps or whatever) of the other unit. There's musical 
>value in doing that sort of thing, but I think that you want to run 
>multiple units in series.
>
>Check out Ken Stone's CGS07. Go to http://www.cgs.synth.net/, click 
>the "PCBs for sale" link and then the CGS07 link. He discusses how 
>to cascade multiple boards, which is what you want to do.
>--
>john