I just checked if there is an API update and it is! Two weeks ago: feat(lp_adc): Added support to read LP ADC from the LP core This commit adds APIs to initialize and configure the LP ADC from the HP core and also adds APIs to read the raw and converted ADC values from the LP core. Source: https://g...

The ESP32-P4-Function-EV-Board is the first P4 board on the market. For me it's a "tryout anything" board. It includes so many interfaces, a microphone and even a physical on-off-switch. This board is for early tests to see what's possible with the enhanced performance and new modules inside the P4 ...

Thank you both for your reply! ... In the end, I'm not sure it's worth the work compared to light sleeping the HP CPU. That's probably why Espressif didn't took the time to implement it, but if you do it, I would be very interested in power consumption benchmark (and the code if you might publish it...

Just an idea: You have spaces in your path. I always avoid theses because in some scripts this leads to problems.

In the datasheet GPIO4 and 5 (and others) are highlighted with reference to chapter "2.3.4 Restrictions for GPIOs and LP GPIOs". Both GPIOs are used for SPI and are "input enabled" at boot time and after. The non-highlighted GPIO or LP GPIO pins are recommended for use first. This should not interfe...

In the documentation for ESP32-S2 and -S3 the API for ULP-RISCV GPIO and ADC is not documented: https://docs.espressif.com/projects/esp-idf/en/v5.2.1/esp32s3/api-reference/system/ulp-risc-v.html#api-reference There are working examples showing some API functions: https://github.com/espressif/esp-idf...

By which value do you increment the sample_counter? I think you need to increment it by 4. The third argument of the ST command is a number of bytes, not words.
See https://docs.espressif.com/projects/esp ... addressing

I have several ESP32-based battery-driven sensors working. In the ESP32-world the board is the main factor. Like NickAllen wrote, the DFRobot boards and some Lolin boards are good for that, I use the Lolin D32 (not "Pro") board. A new DFRobot board with the ESP32-C6 looks good: https://wiki.dfrobot....

How do you connect serial to the PC?
Have you connected RX to TX in both directions?

Which board are you using? Do you have a schematic?
Perhaps there is something connected to GPIO4 onboard.