The Oric was made by Tangerine. I had an Oric-1 back in the 80s, which I sent back to them when they did an offer whereby you sent them your Oric-1 and some money and they sent back an Atmos. I used the Atmos for quite a while, eventually writing a temperature monitoring that printed a continous graph of temperature read from an 1820 sensor on the Oric printer/plotter. I put tat program in ROM and sold the machine to a friend who was after such a device. A few years later I bought thr other well-known Tangerine, the Microtan65. I built that from a kit, but didn’t have the funds for a keypad, let alone a keyboard The plan was to build a keypad, but with no funds for parts, and other things coming along, it was a shelved project. The MT65 was accidentally thrown away, unfortunately. I still have the documentation, though.
So, I’ve had the full set of Tangerine products. Or so I thought…
While looking for Tangerine products on the web I was reminded of the Space Invasion game that was published in Electronics Today International magazine. It was based on a slightly depopulated Microtan 65 plus a sound board and some keys. OK, I haven’t had one of those, so that’s a hole. The searching then threw up what I (now) believe is the first product from Tangerine, the TAN1648. This was a serial terminal (it’s referred to as a VDU, but it allows a keyboard to be attached so I think terminal is a better name) that was designed to provide video output for various computers that didn’t have native versions. It is interesting as it doesn’t have a processor, it is implemented in mainly TTL logic around a UART IC. The UART is one that can be used ‘off-bus’, so the transmit and receive data is accessible directly on pins, perfect for a logic based unit. That seemed to be the full range, until more turned up. The Space Invasion was turned into a product and sold under another name, using a different controller with a 28 pin 6502 device instead of a full 40 pin 6502. It also gained a different name: ’ Brandvance Galactic Invaders’. Nestled in between these early machines is yet another Microtan derivative, which is another magazine published project, also in ETI. This is the Microtutor. It’s a smaller version of the Microtan65 card, but using one of the 28 pin versions of the 6502. It was designed to learn machine code on, and has a built in video output and keypad. It is very constrained in terms of memory, with only 1K of RAM and 2K of EPROM. It does have 1K of I/O space though. The processor used, the 6503 only has 4K of addressable memory, that’s how they reduced the pin count. The keypad is the same as the one used by the Microtan, apart from a missing reset key that has moved to a discrete switch elsewhere on the PCB.
I think that’s it, everything Tangerine made under their own name. They did have dealings with the Nascom video circuit, apparently, but not under their name.
I haven’t managed to find any examples of the Microtutor, so, of course, I used the ETI article to make a PCB and get it up and running. It turns out that it can probably run the Microtan TANBUG unchanged with the addition of a couple of resistors, and definitely runs it if you add a couple of instructions to TANBUG. I’ve also never seen a Space Invasion unit, so I’ve had a go at making that from the ETI articles as well. I haven’t built that up yet.
I’d also like to recreate the TAN1648 (named for the screen character resolution of 16 lines by 48 characters) but the only reference material is a few adverts for it and a magazine cover photograph. If ayone has one, or the documentation, I’d be very interested. Apparently the documenatation contains a circuit diagram.
