Right now is a minimal tour back again to the early 1980s when Mattel launched the DUNGEONS & DRAGONS Laptop or computer Labyrinth Recreation. [Cameron Kaiser] was dealing with a few bins of aged things when he came throughout the activity. Fortunately for us, he made the decision to do a complete teardown and a complete overview a lot more than 40 many years soon after it came out.
The game alone is very basic. You and a close friend are figures on the board, navigating an 8-by-eight maze. As you move by means of the labyrinth, a microcontroller emits twelve audio cues telling you what you’ve operate into (partitions, doors, treasure, and so on). The eight buttons on the aspect allow you to listen to the distinctive tones to know what they imply, as we envision even the most nicely-composed handbook could possibly battle to explain that. In addition, the items are diecast metallic, which allows the activity to detect wherever the pieces have been placed.
With sizeable issue, [Cameron] opened the match to reveal a membrane keyboard pad to detect the distinctive parts. The precise PCB is relatively compact, holding only a one 2N2222 transistor, a couple of resistors and capacitors, and a person 28-pin Texas Devices DIP. When the markings on the chip say M34012, it is a tweaked TMS1100, a descendant of the initial microcontroller. It is a PMOS element, making it possible for it to operate instantly off a 9-volt battery with very little to no regulation. Mattel wanted anything low-priced and customizable to mass develop, and TI had just the design. You could hand them a ROM, an instruction decoder PLA, and an output PLA and get back again a cheap little chip you could get a million of. [Cameron] has an annotated die shot based on an early TI patent and a TMS1000 die from [Sean Riddle].
The chip only has four inputs and nineteen outputs. This tends to make the keyboard hard to scan, but the designers labored about it by employing all the inputs and all but a single of the outputs to study the keyboard. The architecture of the TMS1000 is a bit bizarre, with only a 6-little bit software counter. It breaks the ROM into 16 web pages and has a 4-little bit address register. Having said that, the TMS1100 has double the ROM, so it has a 1-bit chapter latch for the second financial institution. This was no powerhouse, coming at just one instruction for each clock at a measly ~475kHz (approximately as it tended to drift). Total, it is amazing how it does so considerably with so small.
It is a wonderful study that requires you again to how they made factors back again then. Despite all our development in excess of the years, we’d like to see more ingenious, tactile game titles making use of microcontrollers. So though it may possibly not be Holo Chess, this microcontroller-powered game still provides some new strategies even following all this time.