Can anyone identify the micro-controller on a W1209 thermostat board?
The W1209 is a simple very cheap relay thermostat that used to come with TM8S003F3P6 or another unmarked micro-controller in TSSOP20 casing. On this board I recently purchased from Aliexpress the micro-controller is in QFN24 casing and the LDO on the board is now changed to AMS1117-3.3 (instead of the HT7150 on my previous boards) which means it works on 3.3V.
The marking on the board is 808D G00FZ 1617+.

 

It might be a custom Application Specific Integrated Circuit and whether a Microncontroller or ASIC it may be proprietary or a proprietary/customised version.

 

It might be a custom Application Specific Integrated Circuit and whether a Microncontroller or ASIC it may be proprietary or a proprietary/customised version.

Thanks , but i don't think this chip is an ASIC , because there are 4 pins next to this chip for programming and all ASIC chips are unprogrammable .

 

Agreed. I've checked a few mcu in pic16 and stc family with qfn24 footprints but none so far matches the wiring of your chip. Didn't try the avr and stm yet.

 

This page lists some Chinese makers of low-cost microcontrollers; chances are good your chip is from one of them:
https://cpldcpu.wordpress.com/2019/08/12/the-terrible-3-cent-mcu/