ESP32 DAC : Sine Wave Generator

[scruss]

I've been trying to generate simple sine-wave tones using the ESP32's DAC. This article has much of the code to do it: ESP32 In MicroPython: Using Hardware Registers.

Unfortunately, this code only allows very crude steps between frequencies, resulting in truly awful approximation of tunes (for instance: https://xoxo.zone/@scruss/112759584284282346 — beware, it sounds terrible). What I think I'm looking for is the RTC_CNTL_CK8M_DIV_SEL field in the register RTC_CNTL_CLK_CONF_REG, but I'm not sure where that is or how it's applied. Can anyone help, please?

I know I'll likely need to iterate values for this divider along with the frequency step, as suggested in this Arduino code: DacTone/DacTone.cpp · bhall66/DacTone. But that will come after learning a bit more about mem32 things on esp32

[ned-pcs]

You shouldn't have to mess with the RTC clocks to make waveforms if you have a DAC.
Use a numerically controlled oscillator; then you can get very good frequency resolution.