Microvision

[Quadhorn]

How do's,

 

Does _anyone_ have anything on the MB Microvision handheld? I'm looking for any information on what's in the core unit and how to connect to it. Interface details, logic levels and so forth. At the very least, could someone who owns one read the patent numbers off the back, please?

 

I could do with a secondary pet project, something to do when the current one gets stuck or I'm waiting for kit. This may well be it, but I'd like to know more about it before buying one. I've tried looking up stuff myself, but no luck yet.

 

Cheers, QH.

[A.J. Franzman]

From what I've read, all that's in the main unit is the batteries and power supply, controls (pot and touchpad), LCD screen, and driver electronics for the screen. All game logic is in the cartridges, which also have "masks" that limit what parts of the touchpad a player can press. Unfortunately I have no idea what signals are passed between the base unit and cartridges, or how to read/duplicate them.

Edited June 23, 2007 by A.J. Franzman

[Quadhorn]

AJF, cheers for trying.

 

Aye, I've gathered that much about it so far. In a sense it's just as well; a modern processor means a well-supported modern IDE. I'm thinking a flash-based PIC will make a nice cheap single-chip solution, but I've no idea how much or what kind of I/O I'll need nor how much physical space I'll have to fit everything in. I'll have to butcher an existing cartridge for the casing, but ... y'know ... omlettes and eggs ...

[DanBoris]

AJF, cheers for trying.

 

Aye, I've gathered that much about it so far. In a sense it's just as well; a modern processor means a well-supported modern IDE. I'm thinking a flash-based PIC will make a nice cheap single-chip solution, but I've no idea how much or what kind of I/O I'll need nor how much physical space I'll have to fit everything in. I'll have to butcher an existing cartridge for the casing, but ... y'know ... omlettes and eggs ...

 

I have some technical information on my web page about it http://www.atarihq.com/danb/Microvision.shtml including schematics of the base unit and cartridges. On the cartridge page there is a link to the patent for the TMS1100 CPU, and one for the system on the main page.

 

Dan

Edited June 24, 2007 by DanBoris

[Quadhorn]

I have some technical information on my web page about it [...]

Mr. Dan, you are an absolute star. Which is to say that, you have the splendor and wonder of a massive exploding ball of gas in space, held together by your own greatness and shining a pureness of light on everything near you. That is exactly the kind of thing I was hoping for - thankyou.

 

Right, now all I need to do is revive the e-bay account, get hold of one of these pretty pretty's and see what I can do.....

[BigO]

I may have missed this information or this same link on Dan's excellent site. http://www.videogames.org/html/Microvision.../MicrovisionFAQ

(At least one AtariAge regular is a contributor on the document)

 

What caught my attention was the discussion of the LCD controller operation:

 

"The LCD driver chip is a 40 pin chip located in the Microvision base unit.

The lines are Pwr, Gnd, 32 outputs to the LCD, 4 inputs from the

microcomputer, strobe input and latch input. The LCD driver chip is very

primitive. Screen contents must be latched 4 bits at a time, with a

total of 8 packets making up one screen. After all 8 packets have been

latched, they must be strobed in to complete one multiplex. Up to 12

multiplex levels are possible. Finally, the voltage on the LCD must

be inverted by turning the latch on, then toggling the strobe, and

finally the shutting the latch off. The voltage must be inverted

roughly 35 times per second, or the LCD glass will be etched with

electrons."

[A.J. Franzman]

Finally, the voltage on the LCD must

be inverted by turning the latch on, then toggling the strobe, and

finally the shutting the latch off. The voltage must be inverted

roughly 35 times per second, or the LCD glass will be etched with

electrons.

That's bizarre... LCDs do require alternating polarity of balanced duration to keep working properly, but I've never heard of a driver that required external input to accomplish it. Perhaps it isn't a purpose-made LCD driver, but some other device being used as one?

[Quadhorn]

I may have missed this information [...]

The last bit in particular sound a little weird - am I likely to fry this thing if I try to do anything with it? If I ever manage to get my hands on one, I'll get it plugged in to the logic analyser and take a closer look at what it does. Maybe I'll have to look in to some kind of simple emulator for the system, something I can plug the code in to to check it won't fry the screen before trying it on hardware.

[BigO]

I may have missed this information [...]

The last bit in particular sound a little weird - am I likely to fry this thing if I try to do anything with it? If I ever manage to get my hands on one, I'll get it plugged in to the logic analyser and take a closer look at what it does. Maybe I'll have to look in to some kind of simple emulator for the system, something I can plug the code in to to check it won't fry the screen before trying it on hardware.

 

The one I have has a bad LCD. But, based on what little I could see of the LCD and the sounds it makes, the unit is still functional. I've been on a brief hunt for an LCD that I can adapt to these units. I've also thought of driving an LED array as a replacement for the LCD. I also have another more elaborate possibility for the display, but I don't have a lot of time for this project right now.

 

You seem like the right guy to take the documented knowledge of the Microvision workings to the next level. If you think you can learn anything from an otherwise functional unit with a bad LCD, I'll loan you my MV with spare Blockbuster cartridge to run your tests with.

 

Yes, I know it could be accidentally destroyed in the process. Once you're comfortable that you won't destroy the hardware, maybe you can lay hands on a fully functional unit for additional testing.

 

PM me if you're interested.

[BigO]

With a recently acquired unit, I was able to put together a working system. The games are generally good, simple and fun.

 

I can see some potential for homebrew. Once "somebody" has the LCD control scheme nailed down, it should be possible to build a cartridge with a processor, maybe two and a cartridge slot, maybe like the original Game Boy size (?). To simplify programming, one processor could run the game from ROM and write to a display buffer that is read by a second CPU (or timeslices from the first CPU if a fast one is used) and handles the interface with the original unit's LCD controller. Or, somethin' like that.

 

If we ever get around to doing the homebrew thing with the Microvision, I vote for the first game to be a version of Kaboom!