@gilschultz
the schematic is very simple: it is a bare LOLIN S2-mini board: [S2 mini — WEMOS documentation]
And I'm probing the GPIO voltage with a multimeter.
There is no additional HW wired to the GPIOs on the board...
I'running this (stripped) code:
#include <driver/rtc_io.h>
void setup() {
esp_sleep_pd_config(ESP_PD_DOMAIN_RTC_PERIPH, ESP_PD_OPTION_ON);
// sample pins
gpio_pullup_en(GPIO_NUM_16); // no effect
gpio_pullup_en(GPIO_NUM_18); // OK -> GPIO18 = 3V3
gpio_pullup_en(GPIO_NUM_8); // no effect
gpio_pullup_en(GPIO_NUM_10); // no effect
delay(10);
esp_deep_sleep_start();
}
void loop() {
// put your main code here, to run repeatedly:
}