Hello this is my first post,
i am frustrated and need help with my DS3231 RTC.
I have a project where battery power is really important. I use a DS3231 RTC to wakeup my ESP32 microcontroller. My ESP32 has some sensors. It reads it and goes back to sleep, until the RTC wakes him up. To minimize power consumption, I cut down the power of my sensors AND the RTC via a MOSFET switch. The RTC has a battery which keeps the time even when the power from VCC is gone. I want to wake the ESP32 via the RTC in battery mode.
So far so good...
I read in this thread
that the Alarm from the DS3231 in battery mode is just possible, if you remove one resistor block, which I did. I also removed that one resistor which charges the battery.
My DS3231 now looks exactly like this:
Now I am getting the 165.85.165 glitch. This glitch happens if
a) there is a wiring error of the SDA and SCL Pins
b) that you need pullup-resistors of 4.7K Ohm on SDA and SCL
My SDA and SCL Pins are wired correctly. I know that. Seems like I f*** up by removing the resistor block for nothing. I cant write to the RTC properly anymore.
Now I am really confused, regarding the removal of the resistor block. Why would you remove the resistor block just to add them externally again?
Is there really NO way with the resistors on the RTC to get the alarm signal via battery mode?
What options do I have to make this work? I am ready to buy another module of the DS3231 to start over again.
BTW: My ESP32 has also internal pull up resistors for the GPIO-Pins but I read on another thread that these are to weak/not fast enough.