Spin Semiconductor

Can you control a flanger's intensity or width using one of the pots?

Please see the program called "ROM flange/reverb" in the free DPS programs area at http://www.spinsemi.com/programs.php for an example.

That's not what I meant. Can a pot control the deviation in delay range, +/-
so many samples from the center delay. Not mix or feedback or rate.

Well, the simple answer is yes. A POT input is just a value from 0 to 0.99... How you use it in your program is up to you, you can use it to scale other values, write these values to other places (i.e. LFO control) or even to select where to read from a delay line (see RMPA instruction).

Can you give any example code for a flanger range adjustment?

Don't have any example code for that, best I can suggest is see RMPA instruction which is what you would want to use to read from a delay or see the earlier example I pointed at and change the code so a POT input controls the amplitude of the generated triangle wave.

Without the interpolation given by the CHO RDA command won't the sound quality suffer?

He creates the interpolation coeff, that's what the string of "sof" instructions are for.