Hello!

In my project, I'm using the ULP to perform sensor monitoring tasks every few seconds. Once the sensor buffer is full, it wakes up the high-power MCU using the IDF API ulp_riscv_wakeup_main_processor(). The MCU uses an early wake stub to process the data read by the ULP, via shared buffers ...

I have added this to which seems to fix the problem with ULP not running initially:
This also has the nice side effect of releasing the device from the bootloader, if it were manually put in bootloader mode via GPIO0 + RESET.

This github issue also discusses the same bug, which as you say, is due to overflow/underflow or hopping over the end the cycle count (since cycles are not necessarily incremented by one each time, so there's a chance of a miss). https://github.com/espressif/esp-idf/issues/16891#issuecomment ...

Hello!

Does anyone know of a way to access RTC fast RAM from the ESP32-S3 RISC-V ULP? I understand that this isn't supported out of the box, where RTC slow RAM is the default storage for the program and data.

I've read that RTC FAST RAM is intended to be used by the MCU only (APP and PRO cores ...