Working with pots

[livingston]

Sorry for that vague title.

Say I'm using all three pots. Pot1 is to be controlled with an expression pedal. I want to use the others to control the maximum and minimum values that pot1 can sweep through.

Pot0 will control the minimum, Pot2 the maximum. It's important that the setting of one of these does not upset the other, so for example I should be able to set P0 to a value of -.5, P2 to .5, and if I change P0 to -.4, it shouldn't change the maximum value possible (.5).

How can I do this?

[frank]

I'm not sure I understand the problem, the POT inputs are all independent. So if you set POT0 to 0.5 (1/2 Vcc voltage on the POT0 pin) then it is 0.5 and doesn't care what POT1 and POT2 are.

[livingston]

I'm trying to make Pot0 and Pot2 describe 2 numbers, which Pot1 (which is controlled by an expression pedal) will sweep between. So Pot0 should setup the value that Pot1 outputs at "heel down" position, AKA 0v. Pot2 should setup the value that Pot1 outputs at "toe down" position, AKA 3.3v.


I should be able to set Pot0 to -.4, Pot2 to .2, and then Pot1 will sweep between -.4 and .2. Changing Pot0 to -.3 should make Pot1 sweep between -.3 and .2, etc.

[frank]

OK, you just need to subtract value to determine if you exceeded a point. Call them MAX, MIN and POS for the max value, min value and pot position

if MAX-POS < 0 then POS > MAX and set the position to MAX
if POS - MIN < 0 the POS < MIN and set it to MIN

Since POT inputs are treated as registers in an FV-1 you can just use things like

clr
rdax POT2,1.0
rdax POT1,-1.0
skp neg,over
; if here POT1 < POT 2 so all OK
; other stuff...
over:
; if here then POT1 was greater than POT2 so limit the vaue used.