ESP8266 Community Forum

hi,
pcf8523 has a dedicated Vbat pin that should be connected to a coin cell battery.
The chip automatically switches between Vdd and battery.
from the datasheet

If it stops running then there is obviously something wrong with your setup.

see adafruit breakout board https://www.adafruit.com/product/3295

The ESP8266 depends on an internal timer to wake up from deep sleep. If this timer is not accurate enough for your application, you could try adding/subtracting an offset to calibrate it.

If the PCF8523 has the correct date/time after waking from deep sleep, it is working fine.

The TimeAlarms library depends on the CPU running. Since the ESP8266 CPU is not running during deep sleep, these software timers cannot wake up the ESP from deep sleep.

It might be possible to use an external RTC with alarm feature and interrupt out pin to reset the ESP8266 at the wake up time. You must read the PCF8523 datasheet and schematic to see if this is possible.

gdsports wrote:The ESP8266 depends on an internal timer to wake up from deep sleep. If this timer is not accurate enough for your application, you could try adding/subtracting an offset to calibrate it.

If the PCF8523 has the correct date/time after waking from deep sleep, it is working fine.

The TimeAlarms library depends on the CPU running. Since the ESP8266 CPU is not running during deep sleep, these software timers cannot wake up the ESP from deep sleep.

It might be possible to use an external RTC with alarm feature and interrupt out pin to reset the ESP8266 at the wake up time. You must read the PCF8523 datasheet and schematic to see if this is possible.

Thanks alot gdsports. I thought about something like "rtc.always_on" (if someone has a solution like this please tell me) or else to keep the pcf awaken. I was wrong... it's not so simple...

@ Paolo

As long as the PCF8523 has power it should be working. Maybe the problem is with your code rather than the part.

Get this sketch working https://github.com/adafruit/RTClib/blob ... cf8523.ino

Set the clock, then reload the program without the clock setting function enabled. After that you should be able to turn off the power, turn the power back on, read the clock, and the time should be correct. As long as the clock chip has power from the line powered supply, or power from the battery, the clock should keep running.