The question of why the PC clock is so inaccurate, and yet more expensive
than a cheapo watch is simply a matter of "how ya gonna get the
information out of the cheap watch, and into the PC?" The clock itself,
and the crystal are only a portion of the hardware required by a PC to
know what time it is. The additional requirements increase the sicon die
size, as well as the complexity of the design, so the higher cost is to be
expected. If you can get the time out of a cheap watch, in binary form, at
the proper levels, and the proper timing specs, without raising the price
of the $1 watch, a lot of people would like to hear from you ;-)

Well you don't need to get any data only the timeing reference signal. That
can then drive an ordinary RTC chip.

Maybe this could give some ideas?
http://homepage.ntlworld.com/electri...asiowatch.html

A solder connection to the pulsetrain from the 32768 kHz crystal + adjusted
capacitor to the mainboard rtc. Or simple IrDa.