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
Accessing the RTC is done by following steps
- Read 1 or more bits (this resets the recognition pattern; best read at least 64 bits, in case the chip was in the 64-bit data read phase)
- Write the 8-byte (64bit) recognition pattern
- Read or Write the 8-byte (64bit) register data
The 8-byte (64bit) pattern/data is transferred serially, LSB first. The used bits on address and databus are:
A2 data direction (0=write, 1=read) A0 data written to RTC, when A2=0=write D0 data read from RTC, when A2=1=read, and only when pattern recognized
Note: Writes to the RTC chip are performed by using Z80 reads (PEEK) and the A2 and A0 address lines, with the TimeROM+ mapped and at addresses corresponding to where it is mapped.
Recognition Pattern
The recognition pattern is: C5h, 3Ah, A3h, 5Ch, C5h, 3Ah, A3h, 5Ch.
The RTC 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
| Register | Bit Position | Range (BCD) | |||||||
|---|---|---|---|---|---|---|---|---|---|
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | ||
| 0 | 0.1 SEC | 0.01 SEC | 00–99 | ||||||
| 1 | 0 | 10 SEC | SECONDS | 00–59 | |||||
| 2 | 0 | 10 MIN | MINUTES | 00–59 | |||||
| 3 | 12/24 | 0 | AM/PM | 10 HOUR | HOUR | 01–12 | |||
| 10 HOUR | 00–23 | ||||||||
| 4 | 0 | 0 | /OSC | /RST | 0 | DAY | 01–07 | ||
| 5 | 0 | 0 | 10 DATE | DATE | 01–31 | ||||
| 6 | 0 | 0 | 0 | 10 MONTH | MONTH | 01–12 | |||
| 7 | 10 YEAR | YEAR | 00–99 | ||||||
Legend:
- /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
Software
- The TimeROM Software provides RSX commands to use the RTC under BASIC.
- Support for CP/M Plus is provided. The TIMEROM+.COM program sets the software clock according to the RTC. Please use the patched versions of DATE.COM, DIR.COM, SETDEF.COM and SHOW.COM (Y2K Patch).
- TFM's TIMEROM#.COM supports ROM slots 0-127 now.
- TFM provided some routines here.
- The Smart Watch is supported by FutureOS, SymbOS and HDCPM. Source
- The Smart Watch is emulated in WinApe and MAME.
The option to emulate the Dobbertin Smartwatch in WinAPE can be found in Settings/Other/Other devices:
Downloads
- TIME ROM+ ROM file
- MF2_RRB.DSK - Vortex disc, containing the TimeRom+ CP/M driver