ESP32-C3 - Wake up from deep sleep zeroes RTC memory and will NOT report GPIO as a wake up cause

[bricomp]

Board

WeActStudio.ESP32C3CoreBoard

Device Description

Dev board on plug in development

Hardware Configuration

Serial on 20&21.
IO on 4,5,6&7 connected to Teensy (either 3.1 or LC).
Shared ground with Teensy.
Both MCUs connected to USB

Version

latest master (checkout manually)

IDE Name

Arduino IDE

Operating System

Window 10

Flash frequency

80MHz

PSRAM enabled

yes

Upload speed

921600

Description

RTC variables are reset to zero when waking up from deep sleep, also esp_sleep_get_wakeup_cause() always returns zero.
The Teensy (3.1 or LC) is providing the reset signal.

Sketch

#define LED 8  // or use LED_BUILTIN for on-board LED
#define INTERRUPT_PIN 4
RTC_DATA_ATTR int bootCount; // = 0;

void setup() {
    Serial.begin(115200);
    delay(1000);

    pinMode(LED, OUTPUT);
    digitalWrite(LED, LOW);

    ++bootCount;
    Serial.println("Boot number: " + String(bootCount));

    print_wakeup_reason();

    Serial.println("Going to blink the LED 10 times");
    blink(10);
    Serial.println("Going to sleep now");
    Serial.flush();  delay(50);
    esp_deep_sleep_enable_gpio_wakeup(1 << INTERRUPT_PIN,
        ESP_GPIO_WAKEUP_GPIO_LOW);
    esp_deep_sleep_start();

    Serial.println("This will never be printed");
}

void loop() { }

void blink(int times) {
    for (int i = 0; i < times; i++) {
        digitalWrite(LED, HIGH);
        delay(1000);

        digitalWrite(LED, LOW);
        delay(1000);
        Serial.print("Blink ");
        Serial.println(i + 1);
    }
}

void print_wakeup_reason() {
    esp_sleep_wakeup_cause_t wakeup_reason;

    wakeup_reason = esp_sleep_get_wakeup_cause();

    switch (wakeup_reason) {
    case ESP_SLEEP_WAKEUP_EXT0:
        Serial.println("Wakeup caused by external signal using RTC_IO");
        break;
    case ESP_SLEEP_WAKEUP_EXT1:
        Serial.println("Wakeup caused by external signal using RTC_CNTL");
        break;
    case ESP_SLEEP_WAKEUP_TIMER:
        Serial.println("Wakeup caused by timer");
        break;
    case ESP_SLEEP_WAKEUP_TOUCHPAD:
        Serial.println("Wakeup caused by touchpad");
        break;
    case ESP_SLEEP_WAKEUP_ULP:
        Serial.println("Wakeup caused by ULP program");
        break;
    default:
        Serial.printf("Wakeup was not caused by deep sleep: %d\n", wakeup_reason);
        break;
    }
}

Debug Message

Port open
Boot number: 1
Wakeup was not caused by deep sleep: 0
Going to blink the LED 10 times
Blink 1
Blink 2
Blink 3
Blink 4
Blink 5
Blink 6
Blink 7
Blink 8
Blink 9
Blink 10
Going to sleep now
Port open
Boot number: 1
Wakeup was not caused by deep sleep: 0
Going to blink the LED 10 times
Blink 1
Blink 2
Blink 3
Blink 4
Blink 5
Blink 6
Blink 7
Blink 8
Blink 9
Blink 10
Going to sleep now

Other Steps to Reproduce

No response

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[mrengineer7777]

https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/system/sleep_modes.html

[bricomp]

@mrengineer7777 that document does NOT refer to the ESP32-C3!

[lbernstone]

@mrengineer7777 that document does NOT refer to the ESP32-C3!

So go to the top of the page, and switch to the esp32-c3 and IDF 4.4.4.
Deep sleep will shut down any power domains that aren't used. If you aren't using a timer, the RTC domain can be shut down. That page will show you how to ensure it stays up. The wakeup cause should work though. Does it work for you if you use the example without modification (timer based)?

[bricomp]

IDF 4.4.4 was NOT available on the site so I looked at 4.4.5. The paragraph below is an extract from 4.4.5.

In_ ESP32-C3 there is only RTC fast memory, so if some variables in the program are marked by
RTC_DATA_ATTR, RTC_SLOW_ATTR or RTC_FAST_ATTR attributes, all of them go to RTC fast memory. It will be
kept powered on by default. This can be overridden using esp_sleep_pd_config() function, if desired.

You should note from the code above that I am using RTC_DATA_ATTR int bootCount; which should, according to the
documentation, ensure that the RTC is kept alive.

[bricomp]

Does it work for you if you use the example without modification (timer based)?
NO!

Also used the OFFICIAL ESP examples, after modification to suit Arduino IDE, and that did NOT work.

[SuGlider]

@bricomp - What is the Arduino Core version used?

[SuGlider]

I have tested your sketch with Arduino Core 2.0.9 and it works fine.

ESP-ROM:esp32c3-api1-20210207
Build:Feb  7 2021
rst:0x1 (POWERON),boot:0xc (SPI_FAST_FLASH_BOOT)
SPIWP:0xee
mode:DIO, clock div:1
load:0x3fcd5810,len:0x438
load:0x403cc710,len:0x91c
load:0x403ce710,len:0x25b0
entry 0x403cc710
Boot number: 1
Wakeup was not caused by deep sleep: 0
Going to blink the LED 10 times
Blink 1
Blink 2
Blink 3
Blink 4
Blink 5
Blink 6
Blink 7
Blink 8
Blink 9
Blink 10
Going to sleep now
ESP-ROM:esp32c3-api1-20210207
Build:Feb  7 2021
rst:0x5 (DSLEEP),boot:0xc (SPI_FAST_FLASH_BOOT)
SPIWP:0xee
mode:DIO, clock div:1
load:0x3fcd5810,len:0x438
load:0x403cc710,len:0x91c
load:0x403ce710,len:0x25b0
entry 0x403cc710
Boot number: 2
Wakeup was not caused by deep sleep: 7
Going to blink the LED 10 times
Blink 1
Blink 2
Blink 3
Blink 4
Blink 5
Blink 6
Blink 7
Blink 8
Blink 9
Blink 10
Going to sleep now
ESP-ROM:esp32c3-api1-20210207
Build:Feb  7 2021
rst:0x5 (DSLEEP),boot:0xc (SPI_FAST_FLASH_BOOT)
SPIWP:0xee
mode:DIO, clock div:1
load:0x3fcd5810,len:0x438
load:0x403cc710,len:0x91c
load:0x403ce710,len:0x25b0
entry 0x403cc710
Boot number: 3
Wakeup was not caused by deep sleep: 7
Going to blink the LED 10 times
Blink 1
Blink 2
Blink 3
Blink 4
Blink 5
Blink 6
Blink 7
Blink 8
Blink 9
Blink 10
Going to sleep now