RTC_I2C_DATA_REG is not related to i2c peripheral. https://github.com/espressif/esp-idf/blob/3cad00fdcca7dd4b7939d7862407c000c29657c1/components/soc/esp32/include/soc/i2c_reg.h#L264 APB access is preferred but is used by clearing I2C_NONFIFO_EN not setting it. You will have to manage interrupt prior...

Not sure because the driver clears I2C_NONFIFO_EN in both master and slave mode, then proceeds to access the fifo using I2C_DATA_APB_REG(). So I guess if it is set you use I2C_DATA_REG() instead. The way you write more bytes is to set a threshold then receive an interrupt and refill the fifo.

Post the debug output anyway

Is there a difference in debug output?

Oh I see you are saying the idle threshold can't be more than 819us.

What about mcpwm capture?

If you have 12.5ns and 32767 samples per entry so max 409us per entry so your total signal should use max 20 entries

https://github.com/Heltec-Aaron-Lee/WiF ... /issues/39

Onreceive is called in interrupt context from a function that is doing a bunch of stuff that also should not be in interrupt context.