Spin Semiconductor

I figured out how to control frequency and resonance for two pole filters using MULX with a POT input, but these filters do not use RDFX or WRHX/WHLX.

Before I spend the rest of the day slamming my head into the wall I'm wondering if it's even possible to pot control freq and shelf with the RDFX/WR?X combination. If so, a hint would be vastly appreciated!

Update: nice section on this in the Knowledge base. Quick answer = it's a little more complicated.

http://www.spinsemi.com/knowledge_base/ ... ng_filters

This example covers adjusting the shelf depth via control. How about the frequency?

Thx,

DL

Those instructions all require that the coefficient be part of the instruction so you can't use a register for it. If you want an adjustable filter you can't use these instructions and will need to use MULX.

Thanks so much for the clarification Frank. I do have the adjustable shelver working great finally.