ESP32 Forum

Posted: **Wed Oct 25, 2023 3:12 pm**

I am trying to use as little power as possible so I want to turn off the pull-up on one port except when I am reading that port in a wake_stub. However, as soon as I add rtc_gpio_pullup_en(GPIO_NUM_27) to the code in the wake_stub, I get an immediate WDT reboot.

If I enable the pullup before going to sleep, then everything works fine however if my switch (rain tipping bucket) remains closed during the sleep, which it has a 50% chance of doing, then I am using power through the pull-up continuously which I am trying to avoid.

So, the question is, is it not allowed to toggle the rtc_gpio_pullup (that is, do a rtc_gpio_pullup_en, read the port, then do a rtc_gpio_pullup_dis) while in a wake_stub and then return to sleeping?

Here is a code example.
THANKS!

Code: [Select all] [Expand/Collapse]

 
 
// this is an example
// GPIO-17 has a switch to ground
 
#define RAIN_CNT_RTC_GPIO_NUM 17
#define RAIN_CNT_GPIO_NUM GPIO_NUM_27 
 
static void RTC_IRAM_ATTR wake_stub(void)
{
#define PULSE_CNT_IS_LOW() \
  ((REG_GET_FIELD(RTC_GPIO_IN_REG, RTC_GPIO_IN_NEXT) & BIT(RAIN_CNT_RTC_GPIO_NUM)) == 0)
/
  rtc_gpio_pullup_en(RAIN_CNT_GPIO_NUM); // start using power
  if (PULSE_CNT_IS_LOW())
  {
    // do something
  }
  else
  {
    // do something else
  }
  rtc_gpio_pullup_dis(RAIN_CNT_GPIO_NUM); // stop using power
 
 
 // Set wakeup time in stub
  uint64_t time_in_us = WAKE_EVERY_X_SECONDS * uS_TO_S_FACTOR;
  deepsleep_for_us(time_in_us);
 
  // Print status.
  ESP_RTC_LOGI("wake stub: going to deep sleep");
 
  // clear out the UART buffer before going to sleep
  while (REG_GET_FIELD(UART_STATUS_REG(0), UART_ST_UTX_OUT))
  {
  }
 
  // Set the pointer of the wake stub function.
  REG_WRITE(RTC_ENTRY_ADDR_REG, (uint32_t)&wake_stub);
 
  // Go to sleep again
  CLEAR_PERI_REG_MASK(RTC_CNTL_STATE0_REG, RTC_CNTL_SLEEP_EN);
  SET_PERI_REG_MASK(RTC_CNTL_STATE0_REG, RTC_CNTL_SLEEP_EN);
} // end of wake_stub example
 

GeSHi © Codebox Plus Extension

Posted: **Wed Oct 25, 2023 3:50 pm**

I found another discussion about this here:
https://www.esp32.com/viewtopic.php?f= ... lup#p72193

and this page helps a lot:
https://github.com/espressif/esp-idf/b ... .c#L60-L81

Yes, using RTC_GPIO_PULLUP_EN in a wake stub WILL cause an immediate WDT reboot.

Yes, there is a way to do this using bit flipping and yes, like most ESP32 bit flipping, it is cryptic.

Code: [Select all] [Expand/Collapse]

 
//First, in the main code, set up the port: 
#define RAIN_CNT_GPIO_NUM GPIO_NUM_27 
#define RAIN_CNT_RTC_GPIO_NUM 17
 
    rtc_gpio_init(RAIN_CNT_GPIO_NUM);
    rtc_gpio_set_direction(RAIN_CNT_GPIO_NUM, RTC_GPIO_MODE_INPUT_ONLY);
    rtc_gpio_pulldown_dis(RAIN_CNT_GPIO_NUM);
    rtc_gpio_pullup_dis(RAIN_CNT_GPIO_NUM);  // start with pullup turned off
 
// then in the wake stub you can do this
#define RAIN_CNT_IS_LOW() \
  ((REG_GET_FIELD(RTC_GPIO_IN_REG, RTC_GPIO_IN_NEXT) & BIT(RAIN_CNT_RTC_GPIO_NUM)) == 0)
 
 REG_SET_BIT(RTC_IO_TOUCH_PAD7_REG, RTC_IO_TOUCH_PAD7_RUE_M);  // enable pull-up on GPIO-27
 
 if (RAIN_CNT_IS_LOW())
  {
    // do something
  }
  else
  {
    // do something else
  }
 
 REG_CLR_BIT(RTC_IO_TOUCH_PAD7_REG, RTC_IO_TOUCH_PAD7_RUE_M); // disable pull-up  on GPIO-27
 
// then do the other stuff to prepare and re-enter deep sleep  or fully wake up.
 

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