Is there a way to trigger download boot mode by software?

[fanhuanji]

The only way to switch to download mode I've found was to pull some pin physically during power up.
Is there a method to trigger download mode by app?

[ESP_Sprite]

On which chip? The ESP32 doesn't have this, later chips (S2/S3, C series) sometimes do.

[fanhuanji]

On which chip? The ESP32 doesn't have this, later chips (S2/S3, C series) sometimes do.

On ESP32 S3 and C3.
Thanks for reply. Could you give some example please?
Some code snippet will help a lot.

[ESP_Sprite]

You can try:

Code: Select all

REG_WRITE(RTC_CNTL_OPTION1_REG, RTC_CNTL_FORCE_DOWNLOAD_BOOT);
esp_restart();

(Note you probably need to include some headers to make that work, I'll leave that to you.)

[fanhuanji]

You can try:

Code: Select all

REG_WRITE(RTC_CNTL_OPTION1_REG, RTC_CNTL_FORCE_DOWNLOAD_BOOT);
esp_restart();

(Note you probably need to include some headers to make that work, I'll leave that to you.)

Thanks. It works linke a charm.

Code: Select all

#include "esp_system.h"
#include "soc/rtc_cntl_reg.h"
/**
 * @brief Software triggering download mode for ESP32 S3
 * 
 */
void GoToDownloadMode(void)
{
    REG_WRITE(RTC_CNTL_OPTION1_REG, RTC_CNTL_FORCE_DOWNLOAD_BOOT);
    esp_restart();
}

[**txf**]

I have to say that this solution may not work on the S3 (possibly only if you're using USB and TinyUSB in your application). I'm just leaving this here if more people find this thread in a search.

There is a panic in the bootloader. The problem is documented here:
https://github.com/espressif/arduino-esp32/issues/10204