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The [[Dobbertin Smart Watch]] was produced by [[Dobbertin]] Industrie Elektronik, a German company. This real time clock was relative wide spread in the 80ies and 90ies.

== Technicals ==

The SmartWatch consists out of the [[RTC]] itself and an EPROM expansion with a lot of RSX commands. The RTC itself was inserted like an EPROM in any kind of ROM or EPROM card. Further it contains a little battery. At least one clock is still running in 2014!

== Dallas Semiconductors SmartWatch ==

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.

=== 64bit packets ===

D0 data read from RTC, when A2=1=read, and only when pattern recognized

Note: Writes to the RTC chip can be performed by using Z80 reads (PEEK). All that matters is the A2 and A0 address lines.

=== Recognition Pattern ===

The Dobbertin chip requires 64 sequential writes with magic serial data on A0 to unlock it, immediately followed by 64 sequential reads to retrieve the 64-bit time data packet from D0, after which the chip locks itself back into ROM mode.

=== Real-Time Clock Registers ===

* /OSC controls the oscillator. When set to "0", the oscillator turns on and the real time clock begins to increment

* When the /RST bit is set to "0", a low input on the reset pin of the chip will cause the Time Chip to abort data transfer without changing data in the timekeeping registers

== Pictures ==

[[File:RTCdxs.jpeg|720px]]

The expanded version from DXS.

== Software ==

[[File:WinAPE - Dobbertin SmartWatch.png]]

== Downloads ==

* [[media:TIMEROM+.ROM|TIME ROM+]] ROM file

* [[media:MF2_RRB.DSK|MF2_RRB.DSK]] - Vortex disc, containing the TimeRom+ CP/M driver

==Links==

* [[Media:DS1216-smart-watch.pdf|Dallas DS1216 28pin Smart Watch datasheet]]

* [[Media:DS1216-app-note-52.pdf|Dallas DS1216 Application Note]]

[[Category:FutureOS]]

[[Category:Hardware]]

[[Category:Peripherals]]