Working implementation of a Biquad filter for the fixed-point CPU of the ESP8266 #370
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Based off the work of Nigel Redmon (http://www.earlevel.com/main/2012/11/26/biquad-c-source-code/), seems to work A1 with my setup, though it might need some polishing to lower the resources needed for operation. I am currently dividing by two the input sample value to avoid any clipping, but I'm looking for a cleaner solution to this as well!
I have a webradio player build around TFT_eSPI, an ST7735 (128x160 LCD), a rotary encoder and a WeMos D1 Mini for testing, and it crashes after I add a second Biquad filter in the audio pipeline. Is this CPU or RAM-related, that's what I am wondering!