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ESP32S2 ULP/FSM ADC return 0x1FFF (8191) in deep sleep

Posted: Tue Aug 09, 2022 6:41 am
by marc-dsa
When the ESP32S2 is in deep-Sleep the ULP/FSM instruction "adc" return alsways 0x1FFF (8191). It's look like the ADC is internally not powered or not working properly in deep-sleep. The example works fine for ESP32, but do not work for ESP32S2:
https://github.com/espressif/esp-idf/tr ... sm/ulp_adc

On ESP32S2, GPIO7 (ADC1_CH6) is connected to ground, but in deep-sleep the result is always 0x1FFF.
I already try to add this: "esp_sleep_pd_config(ESP_PD_DOMAIN_RTC_PERIPH, ESP_PD_OPTION_ON)", but it's still not working.