Espressif ESP32-S2 User Manual

Chapter 2. API Reference
CONFIG_BOOTLOADER_APP_TEST
GPIO triggers boot from test app partition
Found in: Bootloader config
Allows to run the test app from “TEST”partition. A boot from “test”partition will occur if there is
a GPIO input pulled low while device starts up. See settings below.
Default value:
• No (disabled) if CONFIG_BOOTLOADER_APP_ANTI_ROLLBACK
CONFIG_BOOTLOADER_NUM_PIN_APP_TEST
Number of the GPIO input to boot TEST partition
Found in: Bootloader config > CONFIG_BOOTLOADER_APP_TEST
The selected GPIO will be configured as an input with internal pull-up enabled. To trigger a test app,
this GPIO must be pulled low on reset. After the GPIO input is deactivated and the device reboots, the
old application will boot. (factory or OTA[x]). Note that GPIO34-39 do not have an internal pullup and
an external one must be provided.
Range:
• from 0 to 39 if CONFIG_BOOTLOADER_APP_TEST
Default value:
• 18 if CONFIG_BOOTLOADER_APP_TEST
CONFIG_BOOTLOADER_HOLD_TIME_GPIO
Hold time of GPIO for reset/test mode (seconds)
Found in: Bootloader config
The GPIO must be held low continuously for this period of time after reset before a factory reset or test
partition boot (as applicable) is performed.
Default value:
• 5 if CONFIG_BOOTLOADER_FACTORY_RESET || CONFIG_BOOTLOADER_APP_TEST
CONFIG_BOOTLOADER_WDT_ENABLE
Use RTC watchdog in start code
Found in: Bootloader config
Tracks the execution time of startup code. If the execution time is exceeded, the RTC_WDT will restart
system. It is also useful to prevent a lock up in start code caused by an unstable power source. NOTE:
Tracks the execution time starts from the bootloader code - re-set timeout, while selecting the source
for slow_clk - and ends calling app_main. Re-set timeout is needed due to WDT uses a SLOW_CLK
clock source. After changing a frequency slow_clk a time of WDT needs to re-set for new frequency.
slow_clk depends on ESP32_RTC_CLK_SRC (INTERNAL_RC or EXTERNAL_CRYSTAL).
Default value:
• Yes (enabled)
CONFIG_BOOTLOADER_WDT_DISABLE_IN_USER_CODE
Allows RTC watchdog disable in user code
Found in: Bootloader config > CONFIG_BOOTLOADER_WDT_ENABLE
If this option is set, the ESP-IDF app must explicitly reset, feed, or disable the rtc_wdt in the app’s
own code. If this option is not set (default), then rtc_wdt will be disabled by ESP-IDF before calling the
app_main() function.
Espressif Systems 1065
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Espressif ESP32-S2 Specifications

General

Brand	Espressif
Model	ESP32-S2
Category	Single board computers
Language	English