I got a Timex Data-Link 150S off ebay: www.seanriddle.com/datalink150sf.jpg www.seanriddle.com/datalink150sb.jpg
I count 108 traces coming out from under the big glob. The back of the case lists 2 patents; 4,527,096 for the backlight circuitry and 5,488,571 for the data transfer technology. The '571 patent mentions the MC68HC05HG "including a timer, real time clock system, asynchronous serial interface, synchronous serial interface, LCD drivers, keyboard, switch and electroluminescent lamp outputs", but I haven't found any info about it.
There are 4 smaller globs. Based on their location, I'm guessing one is backlight related and another is data transfer related. I'm sure at least one of the other 2 is a serial EEPROM.
The photosensor and circuitry are mounted on a small daugherboard. Both PCBs are multilayer.