Building Own Version

[overeasy]

That part is a different form factor and significantly different functioning. See this post:

There are no chips

Tell me about it. For those not familiar with the part numbers, those are the real-time-clock and associated 32.768 crystal. They are simply no longer available. I’ve had to find a solution for new units in manufacturing now. The M41T81 is another i2c SOIC8 clock that is electrically compatible as far as footprint and pinout, and also uses a 32.768 crystal. It works pretty much the same as the PCF8523 except that the interface is different. IoTaWatt release 02_06_06 recognizes the M41T81 an…