RTC battery supply

[ESP_igrr]

In the current chip there doesn't appear to be a way to solve this automatically. Essentially you need to provide backup power supply which can last long enough to let the application detect loss of power and enter deep sleep. Detecting loss of power can be done using a GPIO interrupt. Entry into deep sleep can be done from a high-priority task. Wakeup from deep sleep could then be triggered by a GPIO connected to the main VDD rail.

[ctacb_]

The issue seems to be that internal CPU regulator can also take power from VDD_RTC pin, meaning that if all the power rails except VDD_RTC are powered off, CPU can still keep running;

Hi.
CHIP_PU pin was on GND?

Ohh..
https://www.espressif.com/sites/default ... _en.pdf#10

RTC without cpu on esp32 is impossible Have to use DSxxx or something like this.

[kmakhil90]

Hi,

Is there any update on this topic now?

[Sprite]

What news did you expect? There hasn't been an update to the ESP32 silicon, so it's still impossible to do this automatically.

[Ritesh]

Depending on what is the goal... If the goal is to keep just the RTC working in the event of loss of power, then powering VDD3P3_RTC with a battery-backed supply is enough. If the goal is to also save main memory contents, then VDD3P3_CPU should be battery-backed as well (although this will likely need a much bigger battery).

Hello,

I have ESP32 Dev Kit C V4 and I want to keep RTC clock on in case of power supply down. I have button cell with holder and wires.

so how can i connected with ESP32 board to keep RTC always on when main power goes down?

[Sprite]

As I stated in the other thread: The ESP32 does not support coin cell battery backup for the RTC.

[Ritesh]

As I stated in the other thread: The ESP32 does not support coin cell battery backup for the RTC.

which thread? can you please provide link for same?

Also my requirement is simple like is it possible to retain internal RTC clock with updates when main VDD supply went out using button cell? or is there any other was to do like that?

[Ritesh]

ESP_Sprite,

Is there any update regarding last comments with queries which I have given?

[suziyousif]

What news did you expect? There hasn't been an update to the ESP32 silicon, so it's still impossible to do this automatically.

is it possible to do it automatically with esp32s3 DevKit C?

[Sprite]

No, sorry.