[[Image:DS1216E-Drawing.gif|right]]
The 28pin '''SmartWatch''' (DS1216) is an adapter that can inserted in standard ROM sockets, a ROM chip can be mounted on the adapter, finally, inside of the adapter is a 16pin '''Phantom Time Chip''' (DS1315). Normal memory reads are forwarded to the piggyback ROM. After reading from a specific sequence of addresses, the ROM is disabled, and data is instead read from the Phantom Chip via 1bit databus. Writing to the Phantom Chip is done by '''reading ''' from a specific sequence of addresses, too.
* [[Media:DS1315-phantom-time-chip.pdf|Dallas DS1315 16pin Phantom Time Chip]]