the Mattel Dungeons & Dragons Pc Labyrinth Sport and the TMS1100
When my dad and mom bought the home and moved to the nice white north, they dropped off a number of containers of my stuff that was nonetheless within the storage. Now that we’re getting issues cleared away in case we have now to make a transfer of our personal within the not-so-distant future, it was time to undergo these containers, and one of many containers was this, my previous Mattel Electronics DUNGEONS & DRAGONS™ Pc Labyrinth Sport.
That is the larger, extra deluxe of the 2 Mattel devoted D&D video games (the Intellivision in fact had its personal set, and we had a Tandyvision ourselves), the opposite being the DUNGEONS & DRAGONS™ Pc Fantasy Sport. That was a handheld unit with a surprisingly compelling implementation of Hunt the Wumpus, and one thing we’d speak about one other time. This one is extra like a board recreation, however with a pc antagonist and audio.
The field says copyright 1980 however I believe we acquired it late 1982 or early 1983. Both means, I used to be most likely too younger for this recreation on the time: it advertises 8 and up, and I might have been round six or so. It requires you to juggle various completely different audio indicators and construct up the maze and the objects in it (you, your competitor, the dragon, the treasure, your lifeless defiled corpses if you attempt to get the treasure, and many others.). My recollection is that we barely performed it in any respect.
Effectively, higher late than by no means. And hey: let’s discover out what makes it tick. (Teaser: it is 4 bits and we have now an annotated die picture. Learn on.)
Apart from the label being a bit dog-eared, which I corrected with a dab from a glue stick, this factor is sort of mint and all of the items have been there. The unit had an MSRP in 1982 of $55, or about $170 in 2023 {dollars}, so it undoubtedly would have needed to exude a premium air to benefit such a premium value (however I believe my people acquired this at one of many Kaybee Toys gross sales). A helpful slide-out drawer shops the sport objects.
About the one factor that wasn’t mint within the field, apart from the field, was the guide. Nonetheless, I believe it acquired that creased up due to all of the flipping by means of it attempting to determine the right way to play.
At its coronary heart total gameplay is, because the title suggests, a turn-based maze crawl in an eight-by-eight dungeon. The raised indentations between board areas are for putting crimson “partitions” as you run into them to construct up the maze visually. The sport tells you what is taking place with twelve distinctive audio cues; since it’s important to know what they imply, the bottommost six keys on the left play them for you on demand (with the SWITCH key, they play the second financial institution of six). Nonetheless, they’re all pretty distinctive and counsel their meanings properly, so I do not recall we had any hassle remembering them. The fundamental concept is to get the treasure and get again to your hideout earlier than the opposite participant will get it or the dragon will get you. A better problem setting provides “doorways” that randomly open and shut, however that is annoying, and I am fairly positive we performed that mode precisely as soon as. You would most likely play an honest recreation in about ten or fifteen minutes.
A fundamental recapitulation of the foundations is inconveniently on the underside of the slide-out drawer, requiring you to both take away the drawer or perilously flip the board the other way up if you happen to lose the e-book.
The sport runs on a single 9V battery, however you can too use an AC adapter (not included). Because the sticker says, if the sport is performing bizarre, change the battery. I ought to strive that with my cat however I do not know the place her battery compartment is, precisely.
Mattel half quantity molded within the plastic (1991-2109-E © MATTEL INC. 1980).
The items are fairly good. They’re diecast steel and have a lovely heft to them, which undoubtedly helped the sport detect their strain on the play areas and the gamers really feel they did not purchase junk. This is the dragon. He is very detailed.
Listed here are the intrepid dragon feeder mice warriors.
And here is the treasure.
The three inexperienced tokens are for marking the participant’s secret rooms (begin and end) and the place the treasure room was in order that the treasure might be returned there if an unlucky participant loses it. The treasure piece is generally for present as a result of the participant that has it’ll take it, leaving the inexperienced token as a substitute. Nevertheless it appears to be like cool.
The largest obstacle to opening the unit up are these rattling Mattel safety screws. In addition they used them for a time on Intellivision cartridges. There are numerous posts round asking what sort of safety bit will open these, and whereas nothing is seemingly an precise match, my TA2.7 screwdriver appeared to suit properly sufficient to show the screws with a minimal of stripping.
Screws out, drawer out, battery door eliminated. However we’re not finished but!
A sequence of very tight plastic snaps holds the case collectively even with the screws out. It took me a great ten minutes with a plastic putty knife and nylon spudger to crack it open (and it did make some cracking noises within the course of). Don’t, don’t, don’t use a steel spudger or flat screwdriver blade: the plastic bends very simply and I even did a little bit injury with the nylon device which happily is simply seen if the place to look. The toughest half is the facet the place the drawer comes out as the purpose the place the 2 halves meet is recessed and you actually must worm your work device into it.
Separated. This machine is generally recreation pad (a membrane keyboard, actually).
The bottom reveals the a number of layers and conductive traces that join a circuit when pressed collectively. The traces go row and column again to the ribbon connector on the small logic board.
In any other case, there are only a few elements. The speaker — on this view out of body to the left — sits on a blob of what was most likely mounting putty however has since dried out right into a chalky, crumbly lump. Apart from some scattered resistors and a pair capacitors, and a single 2N2222-type bipolar junction transistor, the rest of the board is “dominated” by a small 28-pin Texas Devices DIP labeled M34012-N2LL, dated twenty third week 1982 (in line with my recollection on once we first acquired it). The battery compartment connects to the small swap on the best.
The underside of the board is marked MATTEL, INC. © 1980 1991-9229 REV-C. The opening marked FR is definitely empty; you are simply seeing reflections from the ribbon connector by means of it. Primarily based on what I see right here, the AC jack appears to be like like tip-positive, and also needs to be 9V (the guide would not say). Oh properly, alkaline 9V batteries aren’t that costly.
Let’s speak concerning the CPU. Although the chip quantity may allege this to be associated to the Texas Devices TMS34010, this chip is each means too early and means too small. We’d like one thing easy, cheap and simple to mass produce for a child’s toy, and Texas Devices had simply the ticket.
The M34012 is actually an iteration of the Texas Devices TMS1100 microcontroller, itself an evolution of the unique TMS1000 and {that a} descendant of the TMS0100, which in 1971 was the world’s first microcontroller. These chips include RAM, ROM and I/O all on one die, together with help for phase shows and studying keypresses, all with a really low requirement for exterior supporting elements. The TMS0100 was first used (because the TMS1802NC) within the trend-setting Sinclair Executive handheld calculator and was very profitable in that utility. TI reworked the TMS0100 design into the TMS1000 line in 1974, and modestly upgraded the RAM and ROM to yield the TMS1100 sequence in 1975. The M34012 is a PMOS half, permitting it to run just about immediately off a 9 volt battery or different unregulated provide of comparable voltage.
In contrast to our different favorite recreation microcontroller, the MOS Technology 7600, the place nobody has discovered an information sheet or perhaps a product round but, the TMS1000/1100 household was copiously documented — sufficiently so to even facilitate writing MAME drivers for such games. The output programmable logic array (PLA) and even the instruction decoder PLA have been customizeable: present the PLAs and the masks ROM to Texas Devices with a wad of money, and get again an almost-all-in-one drop-in recreation controller in massive portions. TI not solely used it in their very own shopper toys just like the Converse & Spell but in addition the Milton Bradley (now Hasbro) Simon recreation, the Parker Brothers Merlin, and the Milton Bradley Microvision, the primary handheld recreation with interchangeable cartridges (after the Intel 8021’s energy consumption proved too excessive). By 1979, TI reportedly bought round 26 million components within the household yearly and its NMOS and CMOS descendants have been used properly into the late Nineteen Eighties.
This can be a die-level image of the M34012, graciously offered once more by Sean Riddle, who has comparable die footage of various related devices. I annotated the die off the programming guide and an early TI patent with a TMS1000 die image. The largest options on the die are the 512 bits of RAM (organized into 128 nybbles) and two kilobytes of masks ROM, up from 64 nybbles and one kilobyte of ROM within the TMS1000, in addition to the 2 PLAs.
MAME estimates its clock speed at 475kHz based mostly on the values of the resistor and capacitor nearest the chip, although this worth tended to wander. All directions execute in a single clock cycle. The chip gives 4 inputs (Ok-inputs, for the keyboard traces), and nineteen outputs in two teams, one group of eight concurrently set by the output PLA from a five-bit output register (O-outputs) and eleven extra which might be individually controllable (R-outputs). TI envisioned the R-outputs serving as management traces and the O-outputs for LED segments, however on this recreation all of the O-outputs and all however one of many R-outputs service the keypad; the remaining R-output goes to the speaker. Since there are 4 inputs, there are two halves to the keypad consisting of 4 rows every. The sport energizes every of the 9 columns in every half utilizing a unique output line (thus 18). Any buttons pressed are transmitted again on the Ok-inputs.
The TMS1000 household is Harvard structure, so the ROM occupies a unique tackle vary from the RAM. The TMS1000 has 43 directions, 12 operated by fastened logic and the remaining sequenced by the PLA (within the TMS1100, this was elevated to 54 and a few have been barely altered). Like most corporations, Mattel used considered one of TI’s commonplace instruction decoder PLAs and didn’t use a customized one. Nonetheless, nearly each TMS1000-family half together with this one has a personalized output PLA due to the generally sophisticated mapping of 5 bits onto eight. MAME requires the ROM and the contents of each PLAs to play a recreation.
The Nineteen Seventies birthed loads of odd microarchitectures however the TMS1000 household is unquestionably one of many strangest. The TMS1000 has a 4-bit accumulator (A), a 4-bit Y register (Y), a 2-bit (three within the TMS1100) X register (X) because the RAM web page tackle register, a 6-bit program counter (PC), a 6-bit subroutine return register (SR, i.e., the hyperlink register), a one-bit name latch (CL) to stop the SR from being unintentionally overwritten, a 4-bit ROM web page tackle register (PA), a 4-bit ROM web page buffer register (PB, additionally used with the subroutine return register), a 5-bit O-output register (O), a single standing bit (S) that defaults to true, and a bit every for the R-outputs listed by Y (R(Y)). (The Ok-inputs are learn with particular directions.)
Regardless that every instruction is simply a single byte, a six bit program counter means you possibly can solely tackle 64 bytes of ROM, so PA picks considered one of 16 pages. On startup PA is ready to web page 15 and PC is 0. This system counter wraps, which means after byte 63 comes byte 0 once more in the identical web page, and on prime of that, the one department directions you might have solely department if S is true. To make a far leap or name, you’ll want to be sure S is true (executing a dummy instruction or a known-true to make it so if wanted), set PB to the specified web page (LDP x), after which department (BR): the CPU places PB into PA and begins from the brand new PC within the new web page. Calls (CALL) swap PB and PA to protect the return tackle, which means you possibly can’t make a protracted name from inside a subroutine, and till CL is cleared by a RETN instruction, subsequent calls don’t change SR or PB which nonetheless level to the unique return tackle and web page. As soon as a department executes, taken or not, S turns into true once more.
This system circulation state of affairs turns into a bit extra advanced nonetheless within the TMS1100: now you might have double the ROM, so a set of one-bit chapter latches have been added for the brand new second financial institution. Analogous to SR, PA and PB, you might have CS (chapter subroutine), CA (chapter tackle) and CB (chapter buffer), all zero on power-on. The brand new COMC instruction flips CB. On a department, CA is ready to CB on the similar time PA is ready to PB; on a name, CS is ready to CA as properly so returns nonetheless work.
Likewise, as Y is used as an index into RAM, solely 16 of the 64 nybbles within the TMS1000 might be addressed with Y alone; the two-bit X serves because the RAM web page register and selects the “file.” The TMS1100 additionally has double the RAM, however right here the answer was merely to make X three bits as an alternative and alter the corresponding LDX instruction accordingly. Nonetheless, a doable design flaw solely permits Y to index the R-outputs when the third bit is not set, so COMX was altered to flip solely that new bit as an alternative of complementing your entire register. (Y values 11 to fifteen solely set R-outputs on the expanded TMS1200 and TMS1300 chips, which have 16 such outputs as an alternative of 11.)
The 4-bit adder within the die image does double responsibility as a comparator, and adder output can go both to A or Y — or neither (the small band of circuitry below the adder chooses the vacation spot). Carry or borrow, if there may be one, goes to S. All of the ALU does is add and subtract; there are not any bitwise logic directions. However, the SBIT and RBIT directions can put a 0 or 1 at any bit place in any nybble listed by X and Y, and TBIT1 can take a look at it (bit to S), so any logic operation might be (labouriously) carried out by strolling all 4 bits and setting appropriately.
The accumulator is the one register that may write the O-output register, however as a result of it is solely 4 bits, the fifth bit has to return from S. There are some memory-to-memory directions and even a constant-to-memory instruction (TCMIY), however of the registers solely the accumulator can load and retailer from reminiscence, solely the accumulator can add and subtract with values in reminiscence, solely the accumulator can obtain the contents of the Ok-inputs (although you can too take a look at them as a bunch), solely the accumulator might be in contrast towards (to reminiscence or Y, end result to S) and solely the accumulator can add or subtract a price larger than one.
With all that in thoughts, take into account these applications, immediately copied out of the programmer’s guide. This primary one does a left shift of six nybbles in reminiscence, place 0 being the least important digit, akin to you coming into a brand new digit right into a calculator worth.
lshft cla ; clear A
ldata tcy 0 ; switch fixed 0 to y
l1 xma ; alternate reminiscence listed by Y and the accumulator
iyc ; y++, carry to S
ynec 7 ; s = (y!=7)
br l1 ; department if true to l1
retn ; if this have been a name
If entered at ldata, then the accumulator is put into the LSD as an alternative of zero.
And here is an addition routine between two banks of six nybbles. As a result of that is supposed for a calculator, it does it in binary-coded decimal treating every nybble as a digit. X units the vacation spot of the sum, flipping the higher bit; thus, on a TMS1100 with an X of 0, this implies you’d add the digits in file 0 to file 4 and retailer them in file 0, and so forth. The 1100 lacks the ALEC (A lower than fixed) instruction that the TMS1000 had which prevents a direct take a look at to see if our digit is already in vary, requiring some further footwork.
a040 tcy 0
cla
ad1 comx ; flip X bit 3 (notice: on TMS1000 this flips each bits of X)
amaac ; add m(x,y) to accumulator, carry to S, end result to accumulator
comx
amaac
br gt15 ; department if carry set (larger than 15)
a6aac ; add six to digit. 10 turns into 16, which is zero, and many others. (carry to S)
br gt9 ; larger than 10
a10aac ; add ten to digit to repair a digit lower than 9
tamza ; switch accumulator to reminiscence listed by Y and clear accumulator
br incy
gt15 a6aac ; 16 turns into 6, 17 turns into 7, and many others.
gt9 tamza
iac ; increment accumulator, inverse of carry to S
incy iyc
ynec 7
br ad1
retn
(The AnAAC sequence of directions are literally one group of microcoded directions with a number of mnemonics however a non-standard fixed encoding; CLA and IAC are additionally associated.)
And eventually here is a routine that emits six nybbles as segments on the O-outputs, pulling every R-output low from 6 left to 0 proper in order that the show is aware of which digit is being emitted, in a loop till any secret’s sensed on the Ok-inputs, then debounces that key. This assumes a seven-segment digit-to-LED mapping is within the output PLA.
disp tcy 7
dis1 dyn ; y--, inverse of borrow to S
tma
iyc
rstr ; R(Y)=0
dyn
tdo ; O=A
setr ; R(Y)=1
knez ; any Ok bits set?
br exit ; yup
ynec 15 ; s = (y!=15) which might imply it underflowed
br dis1 ; proceed digits
br disp ; begin over from the left
exit tcy 15
tya ; switch Y to A; cannot load non-zero constants to A immediately
delay dan ; decrement A, inverse of borrow to S
br delay; department so long as we do not borrow
dyn
br delay
; whole delay 544 cycles
For those who really wished the worth of Ok, you might fetch it earlier than the delay with TKA and stash the accumulator someplace in reminiscence beforehand.
Further RAM may be managed by the R-outputs. For a 256×4 bit RAM chip, for instance, the microcontroller may put the tackle on R(0) by means of R(7), Chip Choose on R(8) and Learn/Write on R(9), emit knowledge to jot down on the O-output’s low nybble and browse knowledge on the Ok-inputs. A multiplexing system may permit the traces for use for different functions, although we’re attending to the purpose the place a extra succesful processor could be extra acceptable. Fortuitously for Mattel the small quantity of RAM built-in was clearly greater than sufficient to handle this recreation’s state, gamers’ circumstances and one very cheesed off dragon.
When reassembling be sure to get the little hat again on the ability swap and realign the holes within the membrane keyboard layers with these on the case. It took a little bit little bit of kneading to get every thing seated once more.
And hey, let’s play a recreation earlier than we put it again within the field, with a greater appreciation of how a lot it is doing with so little. Eat mace, die-cast 4-bit-computer-controlled dragon.