Based on the enclosures here
Any guess as to what this microprocessor is? I suspect it is
Has no on-board EEPROM
Has I/O ports apparently named PA0..PA7.
PA4 can wakeup the microprocessor
A port bit PB2 exists
It's within a garage door is open transmitter sold by Chamberlain and Sears
In the photo, the microprocessor, U2 in the schematic, is a chip underneath the round blob of epoxy. The 8 pin IC is the EEPROM.
(disclaimer: The attached documents came from the public-access FCC web site)