Seiko UC-2000/UC-2200

Version Française



I'm looking for the manuals of this computer!


A real mini-computer at your wrist! From 1984...

You can contact Etienne that might be able to answer your questions
as he owns the original manuals.
(preferably in english).
Download the user's manual!
Or if you prefer the user's manual!
Written by myself after long hours of tests
It covers the use of the watch, of the computer and its programmation.

Reformatted to A5 page size
4 new instructions found (see page 28 "Last Minute").


Features Basic Programming Other functions A look inside...

Features of the UC-2000
It's a watch with matrix display capable of 4 lines of 10 characters each:
  1. Upper and lower case
  2. Double heigth digits
  3. Semi-graphic characters
The MODE key allows you to parse the different modes:
  1. Date and time display
  2. Memo A and B display
  3. Run a user loaded application
  4. Chrono to 1/100th sec
  5. Set the alarm
  6. Set time and date


Features of the UC-2200
It's the docking station of the watch:
  1. CPU Z80 (3-4MHz?), 4Kb SRAM, ROM Basic Microsoft
  2. Calculator mode with 4 operations (no memory!)
  3. Thermal printer
  4. QWERTY keyboard with function keys
  5. ROM port for additional applications
  6. Transmission circuit to the watch
First the ROM cartridge.
This is the standard module that came with the machine. It contains various applications.
  • Mount the watch on the transmission circuit, key TRANSMIT
  • Switch the UC-2200 on and type on APL
You're driven to the following menu
  1. DEMO: an animation that shows the machine capabilities
  2. SCHEDULE: agenda with memos you can write
  3. HIT: a fast shoot'em up
  4. RACE: a game where you bet on races
  5. AMIDA: a japanese random game
  6. CARD: a Memory-like game against the computer
Those applications are loaded into the watch (one at a time) and can be used without the docking station. Of course, to write the memos for SHEDULE, you must use the station before...
The transmission circuit:
One can notice that no physical connection is requiered between the watch and the station. The link is done through an induction system! Just mount the watch on it!
From what I've read, this circuit can easely be damaged when changing the battery of the watch, so be careful when you do so.
The thermal printer:
It can print every character that the watch can display, even the semi-graphic ones. A printer line contains 20 characters. It's noisy and slow... When running some application, it prints the error messages to guide you. Let me tell you that the first line I read was a mysterious "Ch" and it went off. Then with other batteries I had "Change Batteries" before it went off again. So I went to the supermarket to buy me some new ones...


Basic Programming


Let's start

  • Mount the watch on the transmission circuit and key TRANSMIT.
  • Switch the UC-2200 on and key BASIC.
  • You get the Microsoft 1983 copyright and the RAM size: 2922 bytes free.
  • Then the "Ok" prompts for your orders
  • To leave BASIC, use the F10 (Shift+F5) key, the program remains in memory!

Program about number precision:

  • Key this program in (sign < is reached with Shift+>)
  • Start the execution with RUN+RETURN or F5
  • It displays 1.67772E+07, this is 2^24.
This shows that the mantissa has 24 bits, only 23 are stored because the first one is always a one. Then 1 bit for the sign and 8 more bits for the signed exponent. Knowing that some values are reserved (zero), you can store values up to 1.1111..x2^126, this is 2^127=1,7E+38. Each real number uses 4 bytes, it is the IEEE encoding for sample precision.


Other functions


Contrast tuning


The Reset after battery change

When you have changed the battery of the watch, you need to perform a reset. Look at the inside of the back cover, a drawing shows you the point that you must short with the + of the battery to make the RESET. If you don't, transmission won't work although your watch seems to work perfectly.

A look inside...


The upper part

This part contains few electronic and is linked to the mother board with a 23 connecter ribbon with:
  • the transmission circuit commands
  • the keyboard connectors

The lower part

Click here for a high resolution image.

Here you find the essential of the electronic!
  • A: The CPU, a Z80 clone, the TMPZ84C01F at 3 or 4 MHz.
  • B: is widely connected to the keyboard, Toshiba T6643 wrongly identified as the CPU on other web sites.
  • C: could it be the RAM controller? SMM 2326F.
  • D: two SRAM chips, 2K x 8 bits, a total of 4Kb.
  • E: LB1246 printer driver.
  • F: location of the 3 batteries 1,5V LR6.
  • G,H,I,J: 4 little ICs, type 40H (367F, 002F, 000F, 373F).
  • K: ROM connector.
  • L: ribbon to the keyboard.
  • M: maybe the quartz for the CPU.
  • N: thermal printer.
  • O: AC connector 3V.
  • P: interruptor that detects wether the batteries cover is closed or not.


15 décembre 2007