For this smoke detector IC, please ?

 

I don't know if you have already looked at this:

https://ww1.microchip.com/downloads...ts/OTH/ProductDocuments/DataSheets/22157B.pdf

 

Thanks to you, I have looked at it now. (Re-purposing that chip)

 

Hi,
XC370696P smoke detector? (Too late).
Good luck ............