Micronic 1000

Last updated on 28-Oct-2000
Contact : minerva9@hotmail.com

The Story

I ordered a couple of devices from Greenweld Electronics, (Greenweld is now under new ownership, good news for electronics hobbyists in the UK), a UK based supplier of surplus electronic goods. Their part number was X8305. I enjoy looking at old bits of kit, especially where an 8-bit microprocessor is involved. The Micronic 1000 is a handheld device with a 4*8 keyboard and a 128*64 pixel backlit LCD display.

Decided to put up this page in case anybody else bought one and wanted to share some info on the device.

Basically, if you have bought one of these & want to make it do anything, you need to open up the case & start looking inside. Of course the unit is surplus equipment & there is no guarantee whatsoever that it will do anything at all. However, the units are well constructed & the units which I purchased run reliably. Sadly, Greenweld has no more of these in stock.

Here is a brief summary of what I have found out so far. Will keep adding to this page as things progress, or at least until I give up trying to get the unit to do something!

The Unit

The unit is said to have been used for stock control purposes (mine had a BHS sticker on it!). The label on the back says 'Victor Micronic (UK) Ltd'. Model Number 875256. Memory 64K/256K. Having had some email from an ex-employee of the Swedish HQ of the company, I now know that they are no longer in business. Apparently most of the units were used for stock control with a bar-code pen (probably attached via the 5pin connector). Seems there was even a batch made waterproof for the counting of trees by the Swedish University of Farming!

It has been designed for handheld use and is powered by 4 * AA batteries which are fitted into the rear of the unit. There is also a CR2025, 3 volt lithium cell which supplies power to retain the contents of the SRAM and RTC inside the unit.

The key parts include :

- Backlit LCD 128*64 pixels (Seiko Instruments C264001) - allows 8 lines of 20 (mixed case) characters
- 4 * 8 keypad with alphanumeric & function keys
- Z840004 CPU
- HD61830 LCD controller chip
- HD146818 Real Time Clock chip
- 256Kb of SRAM
- 2off 27C256 EPROM (in 28 pin sockets, sticker over window easily removed, made by Toshiba, programmed at 12.5V)
- 5 pin connector - on the right hand side of unit (perhaps RS232?)
- IR Rx & Tx - 2 panels (one on the front of the unit & one on the base) each with 2 LEDs for Tx and 2 detectors for Rx
- A buzzer of some description (not sure where this is located).

With the exception of the socketed EPROMs, all of the chips are surface mounted to the PCBs.

Operation

Well, it's not often that I buy some surplus stuff which actually does anything at all without some serious work. However, this unit seems to have a simple monitor built into it which allows some basic operation. Adding some fresh batteries allowed the display to power up. There is a 'master reset' switch which can be pressed by opening the battery compartment & using a pen to push in the small black button which is located to the left of the batteries. The lithium cell is removed by opening the battery compartment & pulling up the black plastic strip which is located at the bottom of the battery compartment.

Holding down the red key & then pressing the adjacent 'light' key caused the backlight to illuminate.

The display contrast can be adjusted by holding down the red key & pressing the 'Enter' key/'End' key. Note: The legend on the 'Enter' key was worn away on my units. The 'Enter' key is the key above the 'YES' key.

The unit can detect when the lithium cell voltage is low. A warning is shown on the display.

The display is blanked after 60 seconds of keyboard inactivity.

If you remove all batteries (including the lithium cell) & then re-insert the batteries the display shows 'TESTING...' then sits for about 1min 45secs before showing a screen :

Parcon 1000
Ram: 256K.B.
DISPOSB Ver 228
To Continue Press >>

Pressing the 'No' key at this point repeats the test, pressing the 'Enter' key moves to a new screen, which requests that you enter the workstation serial number. Enter any number you like & you are taken to a Main Menu which has options :

Load/Run Program, Set Clock, Display Status & Diagnostics. The 'Yes'/'No' keys are used to navigate these menus.

The Load/Run program menu option prompts for a program name and a source.
Pressing the N/Z key shows sources as being V24 adaptor, Plinth, Ext_storage_adaptor, workstation memory & workstation ramdisk

The Ongoing Work

I've disassembled the Z80 code in the 2 EPROMs. This has revealed the following critical routines:

- the address for the 'write a string to the display'
- the address for the 'write a number to the display'
- the address of the 'get a keypress from the keypad' routine
- the method by which the RTC is setup/read

The Outstanding Work

Too many unknown bits to mention at this stage! Still reverse engineering the ROM contents (my Z80 is pretty rusty) - but I've got a really good Pascal to Z80 cross-compiler which will be great, if only we can work out how to get a program into this unit!

Currently the main issues are :

- Still don't know how to access the SRAM. Reckon that it must be 'banked' but can't see how yet. (perhaps something to do with Z80 output port $47 ?)
- Still don't know how any external I/O works e.g. LED Tx/Rx or I/O via 5 pin connector?
- The monitor EPROM code makes many accesses to Z80 I/O ports whose function is still a mystery.

The Downloads

These are pdf files of the relevant datasheets and zips of the ROM contents & disassembled code.
The disassembled listing has been annotated with my comments.
Use this link to access the download area.... Download Area

Excellent News

I contacted a guy who had been looking for info on this unit. Turns out that he has done a lot more work on the Micronic than I have. This includes a monitor program which sounds the beeper & writes to the display. There is also a good description of many of the ports. Many thanks to Lee Davison for sending me some of his work & notes and for allowing me to place them on the Download Area of this site.

The Links

If you are looking for info on the Z80 CPU, Thomas Scherrer has a fine site at http://geocities.datacellar.net/SiliconValley/Peaks/3938/

An excellent Pascal to Z80/Z180 cross compiler at http://users.iafrica.com/r/ra/rainier/

The freeware Z80 disassembler which I used to work on the EPROM contents here

Frogbit, a tool for scanning text files. Good for spotting patterns in code at http://www.axiomati.demon.co.uk/

Some work I did on a Pascal to 8051 cross compiler at http://geocities.datacellar.net/SiliconValley/Campus/9592/

Greenweld Electronics - The surplus supplier who sold these units is now under new ownership. The new owner has now issued a catalogue. Register your interest and buy on-line at http://www.greenweld.co.uk

Contact

If anybody else has been mad enought to buy one of these and is keen to see it do something other than gather dust, please get in touch. Email to minerva9@hotmail.com & we can share any info.

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