unrealeased atari VCS keyboard

[SpaceDice2010]

Also...

 

The keyboard really took a turn and became too much of a computer and not an "add-on" as it was intended to be.

[John_L]

Thank-you for this; I have not seen these photos before.

 

Is it just me, or does the screen shot of the Unitronic Expander look suspiciously like the screen from a Coco? The colour scheme is correct, and there is a maximum of 32 characters per line.

http://www.2600connection.com/faq/vcs_nr/vcs_nr.html#expander

 

Now, this system could also be using a Motorola 6847 video chip (it was used in a few things other than Coco), but that is definitely not the best choice for a game system.

 

The "space invaders" screen shot is definitely not derived from the same video hardware; the colour palette does not match the 6847.

 

There's no doubt in my mind that's an MC6847 VDG chip. It was developed as part of the 68xx series chips to support the 6809 CPU and MC6883 Synchronous Address Multiplexer that Motorola, Radio Shack, and the University of Kentucky used to develop the Radio Shack "VidTex" Terminal. There were some agricultural databases out there that farmers needed access to, and instead of a full blown home computer emulating a VT100 teriminal, Radio Shack though that they could produce a cheap VT100 terminal with a built in modem so farmers could access these online services cheaply. The thing is, it was a niche market within a niche market (only large farms needed this service). Although it was a nice, cheap, affordable system, it didn't sell well due to the small base of users who could take advantage of it, so Radio Shack basically changed out the VT-100 software in ROM for a BASIC interpreter by Microsoft and added additional ports (2 joystick, a cassette port and a cartridge bus) and voila, the CoCo was born. The 6847 made it into the MC10 and a number of other systems too, and the GIME chip developed for the CoCo 3 emulated all the functionality of a 6847 too.

 

Onto that space invaders clone......

 

I think they were pulling a fast one, because what's shown is Space Assault written for the Radio Shack Color Computer....

 

 

I did a bit further research... Space Assault was licensed to Tandy by a company called "Image Producers Inc" in 1981... maybe they were planning on buying a license from them for the expander system

Edited June 20, 2014 by John_L

[Bill Loguidice]

 

There's no doubt in my mind that's an MC6847 VDG chip. It was developed as part of the 68xx series chips to support the 6809 CPU and MC6883 Synchronous Address Multiplexer that Motorola, Radio Shack, and the University of Kentucky used to develop the Radio Shack "VidTex" Terminal. There were some agricultural databases out there that farmers needed access to, and instead of a full blown home computer emulating a VT100 teriminal, Radio Shack though that they could produce a cheap VT100 terminal with a built in modem so farmers could access these online services cheaply. The thing is, it was a niche market within a niche market (only large farms needed this service). Although it was a nice, cheap, affordable system, it didn't sell well due to the small base of users who could take advantage of it, so Radio Shack basically changed out the VT-100 software in ROM for a BASIC interpreter by Microsoft and added additional ports (2 joystick, a cassette port and a cartridge bus) and voila, the CoCo was born. The 6847 made it into the MC10 and a number of other systems too, and the GIME chip developed for the CoCo 3 emulated all the functionality of a 6847 too.

 

That's not completely accurate. We discuss what happened in detail in "CoCo: The Colorful History of Tandy's Underdog Computer," but essentially "Green Thumb" was the agricultural product that both the VIDEOTEX and CoCo grew out of/were inspired by. The VIDEOTEX and CoCo were developed concurrently and on the market at the same time. The video chip was used elsewhere and earlier, including in Percom's Electric Crayon add-on for the TRS-80. While Tandy and Motorola's relationship was nothing if not "cozy," there was no exclusivity agreements in terms of chips.

[The Usotsuki]

I need to add that video mode to my 6847 emulation still, but can't motivate myself. x.x

[John_L]

While Tandy and Motorola's relationship was nothing if not "cozy," there was no exclusivity agreements in terms of chips.

I never said there was.. I just mentioned that the 6847 and 6883 SAM chip were designed by Motorola for the VidTex terminal (AgVision). You're right in that both systems were started at the same time, but the terminal came first, then the computer was modified from the terminal. They actually both went on sale about the same time with the AgVision system tanking pretty fast. Also, the Agvision software, Videotex, was released as a ROM cartridge, so as time went on and CoCo's dropped in price it was easy to emulate the terminal function through the home computer.

 

 

I stated what I did per this wiki article...

 

The TRS-80 Color Computer started out as a joint venture between Tandy Corporation of Fort Worth, Texas and Motorola Semiconductor, Inc. of Austin, to develop a low cost home computer in 1977.^{[citation needed]}

The initial goal of this project, called "Green Thumb", was to create a low cost Videotex terminal for farmers, ranchers, and others in the agricultural industry.^{[citation needed]}This terminal would connect to a phone line and an ordinary color television and allow the user access to near real-time information useful to their day-to-day operations on the farm.

Motorola's MC6847 Video Display Generator (VDG) chip was released about the same time as the joint venture started and it has been speculated that the VDG was actually designed for this project.^{[citation needed]} At the core of the prototype "Green Thumb" terminal, the MC6847, along with the MC6809 Microprocessor Unit (MPU), made the prototype a reality by about 1978. Unfortunately, the prototype contained too many chips to be commercially viable. Motorola solved this problem by integrating all the functions of the many smaller chips into one chip, the MC6883 Synchronous Address Multiplexer (SAM). By that time in late 1979, the new and powerful MotorolaMC6809 processor was released. The SAM, VDG, and 6809 were combined and the AgVision terminal was born.

The AgVision terminal was also sold through Radio Shack stores as the VideoTex terminal around 1980. Internal differences, if any, are unclear, as not many AgVision terminals survive to this day.