All my content and ptohos
Transled LED display driver
This device is quite rare. Manufactured in conditions
far from professional in late 1980s or early 1990s, it is a Z80-based microcomputer
specialised to drive LED display, probably one of these displays with
scrolling text. These scrollers were very popular in Poland in early
1990s.
Inside, most TTL logic chips are Polish, made by Unitra CEMI, but Z80,
EPROM, 8255 and RAM are foreign. Keyboard is identical to one used in
early versions of Unipolbrit 2086 computers (even the far reset button
was in it, but was removed, it's cut off keyboard's PCB), but markings are scratched
from keys and stickers
are applied.
In the rear it has a potentiometer which drives internal oscillator
(probably text scrolling speed) and 5-pin DIN connector which is for
supplying both power (9-12V DC) and output 2 logic signals from device.
| Manufacturer | Transled |
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| Origin | Poland | ||||
| Year of unit | 1989? | ||||
| Year of introduction | ??? | ||||
| Type | Driver | ||||
| CPU: Z80 RAM: 8kB Battery backup (CR1620, not present in photos because it leaked) I/O: Keyboard, 2 pins output for LED display. Most I/O is done with 8255 circuit. Power: 9-12V DC, internally regulated to 5V.
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CR1620 battery is supplying power for RTC which allows to display current time on LED screen from time to time.
[UPDATE: Feb 2017] Recently I have acquired second one, which is newer, from 1991 and is made more professional way. PCB is similar, construction is similar, but keyboard is different. Previous unit has keyboard which was previously used in Unipolbrit computers. Mk. 2 unit, as I called it, have keyboard from Tesla Ondra computers, used as alternative one (see this post). Its casing has vent holes and is smaller, but wider. There is no metal heatsink and transistor is kept on large part of mainboard used to spread heat, so its color changed during operation. Operating system of Mk. 2 allows to scroll text vertically too.
Because I had no idea about this company I've started from
analysing ROM dump. In Poland, there were at least 3 small companies
called Transled, one probably exists now (2014) but it's not this one,
all of them were in LED or lighting business. Finally, by looking into
ROM I've found that TRANSLED's contact information is:
Transled, Kraków ul. Szlak 37 tel. 33-05-89.
This is an address and telephone. I've phoned them - the phone is before
adding 7th digit to Cracow's phone numbers and does not exist anymore
(with adding 4 or 6 too).
More, I've been in their "then-headquarters". Asked, but got no
information as companies and services often move in this location. The
only information I got from hairdresser nearby that there was some
electronic company in 1990s.
The ROM of Mk. 1 is version 6.0N and its number is 72, whatever it means. I've also found information that there's a support for Cyrilic characters.
Mk. 2 has ROM version 9.7 from October 1991. Other ROM is 8.8 from March 1991. It also has supoprt for configuration in few languages other than Polish.
DIN5 connector:
1 - Output Data
2,4 - GND
3 - Output Clock
5 - +9-12V DC (internally regulated to 5V)
UPDATE: For a complete analysis of signals it outputs, look at this article in my site.
-----Outdated as May 2015 ------
If you're curious about its protocol, I've dumped digital data from both output pins using TFLA analyser. You can download data (loadable by TFLA software and in a large CSV file) here.
