[sdiy] CMOS 4516+4067 questions

[Chris Crosskey]

hi Folks...I'm designing a 16-step Digisound compatible 16-step sequencer
and have a bit of a dilemma about the CMOS side of it....I'm planning on
using a 4516 counter to generate  the 4-bit code to control a 4067 MUX/DEMUX
chip. THe way I'd figured out to do the CV channels was to have a 4067 for
each set of 16 and to run a 51K resistor from +15 V to the common pin, then
have each demuxed output go to a 100K pot, thus getting 10V across the pot.
These would then all feed 100K resistors into an inverting summer, which
would then feed to the main I/O board where another inverting buffer would
turn it the right way round and send it to the oputside world......

First question...is this a right/sensible way to do it.....this sequencer
could end up with 12 or more banks of 16 steps when finished (I want to use
it onstage), I didn't want to have 200 odd pots permanently powered, this
way only one pot per bank at a time is drawing current ( I know it isn't a
lot but 200 of them would be more significant), also the fact that ther are
resistors both sides of the 4067 should provide some protection in fault
conditions......

Number 2....a 4516 will auto-reset when it reaches the end of 16 steps won't
it?....Daft question but it isn't addressed in the timing diagram in the
datasheet......

Number 3: What sort of fan-out will I get out of a 4516?...I think I need
five plus the buffers below on the main panel, will I get that OK?

Number 4: If I use a TL074 to buffer the outputs will I be able to send the
four-digit output of the 4516 out to another board?

chrisc