Franz Morat KG tv-computersystem 6800
Lately, there was a pc on ebay.de which I by no means heard about earlier than which turned out to be the quirkiest, most attention-grabbing and revolutionary mannequin I discovered about in a very long time. Nobody else bid on it, so I acquired it for a low value. It’s now the oldest laptop I personal. Meet the 1976 “tv-computersystem 6800” of the Franz Morat KG.
No, that is neither an influence provide nor measurement gear though the very generic metal case (in a becoming Seventies orange) and the very clear entrance plate (one on/off swap and a factor on a cable is all you get) definitely seem like that sort of devic
It’s made by a small German firm referred to as Franz Morat KG from the Excessive Black Forest muncipality of Eisenbach with about 2000 inhabitants. The corporate focuses on mechanics, customized drives, and plastic merchandise. The muncipality and your entire area is well-known for his or her watch business (assume cuckoo clock in case you are into stereotypes). So, in about 1975 somebody from this industrious firm decides that that is the proper time for a pc product.
At the moment, computer systems have been a really unusual sight in Germany. Huge firms may need some very costly, very massive computer systems to do all this information processing witchcraft, however dwelling computer systems won’t actually arrive in Germany till 1978 (with the Commodore PET 2001). Engineers can amuse themselves already with laptop kits, however they require at the very least soldering skills. The usual interface for a small laptop as of late is an extended row of switches and lights that present the content material of a single reminiscence unit in binary. Whenever you need to have a bit flipped, you actually flip the corresponding swap.
However, being the artful German engineer that you’re, you determine to make a quite simple, comparatively low-cost laptop which you can produce simply in-house and that individuals will purchase as a result of they need to be taught to program computer systems. Keyboards are fairly costly and can’t be produced in-house. So, what a couple of purely digital enter system, let’s say a lightweight pen? What, you don’t know what a lightweight pen is? Meet the primary broadly used direct enter system for “graphical” person interfaces. It consists merely of a photograph diode mounted on the tip of a pen linked to the pc. When the diode sees a lightweight it signifies that the electrode beam of your CRT simply handed beneath the place of your pen on the display and confirmed a white pixel. The pc could be very conscious of this place as a result of it controls this beam with a purpose to produce an image on the display. Mild pens are used for the reason that Nineteen Fifties and have been widespread on the graphics terminals of the Nineteen Sixties. Utilizing a lightweight pen additionally means utilizing a CRT show. Hmm, that’s a price problem. Pc displays are very costly (at the moment). Effectively, there’s one CRT show already 93% of all households in Germany personal in 1975: a TV. So, lets produce an antenna sign for a TV to show.
Now, utilizing a TV to point out the output of a pc in 1975 or 1976 is an enormous innovation. From 1977 onwards, most dwelling computer systems use a TV with a purpose to save price. However in 1976, solely video games consoles connect with TVs and till November 1976 when the Fairchild Channel F hits the (US) market, recreation consoles don’t even have microprocessors. I’m positive there’s a pc mannequin on the market that linked to a TV out-of-the-box earlier than the tv-computersystem, however I couldn’t discover it. So, I declare that this mannequin is the primary and look ahead to the indignant feedback to show me improper 🙂
The ensuing laptop due to this fact has solely 3 leads: One gentle pen, one energy cable, one TV antenna cable, all completely linked to the pc so you can not lose them. Contained in the field, the structure is kind of easy: you’ve got a microprocessor, some small RAM (1kB), a 0.5 kB ROM (the preliminary brochure notes it down because the OG Intel 1702, the primary obtainable EPROM), a easy energy provide, and quite a lot of discrete logic. All the pieces is housed on 5 PCBs, 4 of them linked on the edges with what could be these days could be edge connectors and ribbon cables (or perhaps a backplane), however what is definitely an extended line of single wires connecting every PCB in a bus method.
The PCBs slot in slits of easy items of plastic on the underside and on the highest: voilà the completed laptop, at the very least the essential model. The essential model would have price you 1294 DM, roughly a 1/10 of the value of the (then new) VW Golf GTI. In the event you spent 650 DM extra, you possibly can purchase the posh “C” model of the tv-computersystem that gave you a cassette interface and and exterior 37-pin bus interface.
To set this value in relation: in the identical problem of a German electronics journal that says the tv-computer one other article describes the non-public construct of one other 6800-based laptop with a TV interface with lower than 1kB of RAM however a keyboard imported from the US for a part price whole of 2000 DM.
Let’s discuss somewhat bit in regards to the logical structure of this laptop. What would possibly astonish you (it definitely did astonish me) is that the essential mannequin doesn’t have any ROM in anyway. None. Okay, you would possibly say, the place is the firmware? Is it a “clear laptop” like some Sharp fashions that even has to load the firmware from a cassette? The reply isn’t any: there is no such thing as a firmware (at the very least within the fundamental mannequin). All fundamental performance of the pc is completed in {hardware}. The person interface? Performed in {hardware}. The sunshine pen administration? Performed in {hardware} (truly there’s an article in a German digital journal aptly named “Elektronik” from September 1975 that describes this latter circuit and it’s in all probability written by the person who designed at the very least the circuit for the tv-computersystem). The microprocessor isn’t a lot an enabler on this laptop, it’s the “system-under-test”, or, extra accurately, it’s, along with the RAM, the mannequin of a pc system the system exposes so the person can learns its methods. From this perspective, the selection of the concrete CPU mannequin isn’t actually vital, and now it doesn’t shock us that the producer supposed to supply totally different CPUs for it.
Now you would possibly say, however, wait, I simply noticed you speaking a couple of 0.5 kB ROM, what’s all this no-firmware nonsense? Ah, you see, this ROM solely incorporates the library for utilizing the cassette interface within the prolonged “C” mannequin. And it’s only obtainable as a library. Whenever you need to retailer to or learn from a cassette tape, it’s essential to write a small program calling the corresponding library subroutine and begin it.
Okay, sufficient in regards to the structure. Let’s discuss in regards to the person interface (and keep in mind, we’re nonetheless speaking about {hardware}). Right here it’s:
That’s all you get. The UI (mainly a classical monitor) means that you can see the content material of the RAM and to manage the CPU, all of which occurs by utilizing the sunshine pen. On the left aspect on nearly all of the display you may see 32 bytes of reminiscence both as hexadecimal numbers or as bits. Every of those values has to suit right into a 16×16 grid of cells. Every cell has a dot on the high left nook which is the goal for the sunshine pen if this cell is to be chosen by the person. Subsequent to the dot is the area for a single character, e.g. an hex digit. The remainder of the controls could be seen on the proper: a column with the 16 hex digits (every one in the identical cell construction as within the values desk) and a second column with the controls, additionally in cell construction. The controls column permits to scroll the values desk via the reminiscence, to set the worth of one of many values desk to a sure worth, to fireplace an interrupt, to begin, cease, and proceed the execution of a program, and to single-step via a program.
Let me iterate as soon as once more that each one the issues that you simply see are generated by circuits with out the assistance of the microprocessor. There is no such thing as a bitmapped graphics and no textual content reminiscence. When the content material of a RAM web page modifications and if this web page is the one you’ve got chosen for show, you will notice this replace in a short time.
As a result of the UI is hard-wired, it’s also possible to not change it. There is no such thing as a command to show one thing on the display. When your program desires to output one thing, you alter the worth in a reminiscence cell and hope that the person is presently watching this web page (or, much less sensationally formulated, for any program you inform the person on which web page he/she will be able to see the outcomes. That is performed e.g. for the instance packages within the [Book].
So, does this imply {that a} program can not output something graphical? Effectively, you may, in a manner. Keep in mind that I instructed you that the UI can show values both as hex digits or in binary (and that I, sneakily, confirmed you solely an image of the hex mode)? Here’s a image of the binary mode:
As you may see, now the factor with the 16×16 worth matrix is sensible. In hex mode, you want solely 4 cells per worth (as a result of a 16-bit worth could be expressed as 4 hex digits), however in binary, you want 16, and your entire cell area is displayed both black (being a 0) or white (being 1). You might argue that this is some type of bitmap graphics with the sensational decision of 16×16 pixels and two colours and that you’ve got even 32 user-selectable pages of those graphics (and that you’ve got a textual content mode with the small restriction that’s can solely present 10 digits and 6 (massive caps) characters in a 4×16 grid. However it might be a bitmap and textual content mode the place the output reminiscence can be the code reminiscence, and it’s a bitmap the place the person may also change the bitmap interactively. In each case, in my view, it’s ingenious and positively saves quite a lot of parts that don’t have to be designed for the pc and never being paid for by the customer.
Due to all of that, programming on the tv-computer is relatively bleak. In fact, there is no such thing as a larger programming language, not even a symbolic assembler. It’s important to convert your assembler program (e.g. by utilizing the supplied paper programming types) into numbers your self which you then put into the reminiscence utilizing the UI. Whenever you have been prepared, you choose “run” on the display and hope for the very best. One benefit of the used Motorola 6800 processor is that it dumps its registers into reminiscence after every interrupt, so in single-step mode, you may straight see the outcomes of your assembler instructions. The opposite facet of being bleak is that you simply actually get a deep perception into the 6800 machine code, that the pc is (very comparatively) low-cost, and that extra consolation at the moment comes with a hefty price ticket, and plenty of laptop customers are nonetheless accustomed to utilizing computer systems with switches and lights. The Altair 8800 laptop was launched solely a yr prior and so was Microsoft Primary.
The tv-computersystem got here with a German 250-page handbook ([Book]) that describes utilization of the pc and 6800 machine code intimately and incorporates many instance packages. BTW, I scanned a replica:
Fashions
It’s troublesome to actually inform what fashions actually exist. The brochure talks about 6800-, 8080-, and SC/MP-based variations, however I by no means noticed the rest than the 6800-based one. The brochure talks about two fashions, the “G” one (G = Grundausführung = fundamental mannequin) and the “C” one. The “C” one incorporates a DIN (audio) cassette interface and an exterior, 37-pin extension bus whereas the “G” model doesn’t have these luxuries. The pricelist additionally refers to 8080 “G” and “C” variations (having the identical value as their 6800 counterparts). In actuality, I noticed two variations. My model is an orange, metal case “C” model with a single (energy) swap on the entrance. The homecomputermuseum.de mannequin has a pleasant wooden case, and an extra swap on the entrance (marked “RAM”) and appears to be a “G” model the place the PCBs on the within are mounted by a single screw, which doesn’t exist in my mannequin.
I imagine the tv-computersystem was bought actually solely in Germany, however within the references you could find an one-page advert for it within the UK-based journal Electronics Right this moment from 1977 from an organization referred to as Rotex which could have been positioned within the Netherlands.
ICs inside my tv-computersystem
The CPU is after all an authentic gold-capped Motorola M6800. The RAM consists of 8 2102-1PC 1 KB x 1 bit chips of various producers. There’s one MMI 6341-1 PROM (512 bytes) in a socket subsequent to a different, empty socket. There are 2 MMI 6331-1J chips which appears to be NiCR PROMs with the big capability of 32 x 8 bit every, so 64 bytes in whole. The remainder appears to be discrete ICs. No different Motorola 68xx household chips could be discovered. The 64 bytes of PROM resolve an issue I used to be questioning about for a while. In case your base, “G”, mannequin has no ROM how do you produce the hex digits on the display? The digits are in a 5×5 pixel matrix and also you want 16 of those digits. This implies it’s essential to symbolize at the very least 25 * 16 bits or 50 bytes. This matches very nicely right into a 64 bytes area…
From a collectors perspective, this laptop, in my view, is a dream. It’s an early, quirky laptop with revolutionary, uncommon options that could be very, very uncommon, even in Germany. It’s a self-contained unit the place each vital cable is mounted to the unit and can’t get misplaced. It may be linked to a TV. It’s just about unknown in Germany, not to mention another nation. It has in depth documentation (even whether it is fully in German). As it’s so unknown, the costs are (presently) fairly low.
Technical Information
Producer: Franz Morat KG
Mannequin: tv-computersystem 6800
CPU: Motorola 6800@perhaps 1MHz
RAM: 1 KB
ROM: 64 bytes + 0.5 KB (“C” mannequin solely)
Decision: 16 x 16
Colours: monochrome
Interfaces: energy cable, television antenna cable, lightpen cable, 37-pin extension bus, cassette interface (DIN 5 pin)
Dimension: 255mm x 115 mm x 190mm
Weight: ~3.5 Kg
Preliminary Worth: 1295 DM (“G”) or 1954 DM (“C”)
Launched in: 1976
Produced gadgets: 2000 (estimated)
References: