DanBoris

Arcade manuals were mainly for use of the operators of the games so they contain information on how to setup the game, how to set configuration options, some minimal game play information, and very often detailed technical information and schematics that may be needed to service the machine.

Not sure what schematics you are looking at but the TIAEN signal doesn't goto the TIA CS pins. It goes two places, one to control the joystick mode, and one to disable the TIA video output. You may be misreading CS2 which goes to the signal TIACS which comes from MARIA. Dan

Now that I have drawn out the schematic, this actually makes sense. In this configuration both transistors would be on so when the button is pressed there would be almost a direct connection from +5 to GND which could cause exsesive current to flow through the transistors and possible damage them. In the 7800 sticks there are resistors to prevent this. Dan

Ok, after studying the 7800 joystick circuit for a while I think I understand how this all works. Here is a schematic that shows one of the two 7800 joystick ports and how a 7800 stick and 2600 stick attaches to it: In 7800 2-button mode, TIAEN is low which turns on Q8, RIOT PB2 is low which turns on Q6 which effectively puts a +5 on pin 6 of the connector. As a result TIA-I4 will always read hi, TIA-I1 will read hi when the left button is pressed, and TIA-I0 will read hi when the right button is pressed. In 7800 1-button mode, TIAEN is low which turns on Q8, but RIOT PB2 is high which turns off Q6. Pull-up resistor R40 will keep I4 high until either the left or right button is pressed which will pull TIA-I4 low. I am assuming that in this configuration TIA-I1 and TIA-I0 will always read low. Dan

Despite what the header files says Bits 2 and 4 on RIOT Port B actually have a function, they are used to setup 2 button mode on the joysticks. When these bits are set low you can read both button independently through the INPT0/INPT1 and INPT2/INPT3 inputs. Dan

One of the games I remember from the good old days with my Atari 800 computer is the dungeon crawler Telengard by Avalon Hill. The game was written in Basic so I thought it would be interesting to take a look at the code for the game. One of the most interesting parts is the way the maze if generated. The dungeon in the game is very large, it has 50 level and each level is 200 by 200 rooms. The dungeon is also the same every time you play so you can map it out as you go along. I was really curious how the achieved this. The programmer did it by using a pseudo-random algorithm to generate the map. This results in a map that is complex enough to be interesting, but not so complex that it's unplayable. This is the formula that is used to determine the appearance of each room: XO = 1.6915 YO = 1.4278 ZO = 1.2462 q = x * XO + y * YO + z * ZO + x * YO + y * ZO + z * XO hi = q And &HFF q = x * y * ZO + y * z * XO + z * x * YO If (q And 3) = 0 Then q = (q / 4) And &HF If q > 9 Then q = q - 9 hi = hi + q * 256 End If XO, YO, and ZO are constants z = dungeon level x,y = room position in level This formula is run for each room that is displayed and the result, hi, is interpreted as follows: bits 0,1: Upper wall: 0,1 = nothing, 2 = door, 3 = wall bits 2,3: Left wall: 0,1 = nothing, 2 = door, 3 = wall bits 8-11: If not 0 then there is something special in the room 1 = Inn 2 = Pit 3 = Teleporter 4 = Stairway 5 = Alter 6 = Fountain 7 = Cube 8 = Throne 9 = Box The bottom wall and right wall of a room come from the left and top wall of adjacent rooms. There is also code that knows to cap the right side and bottoms of the rooms at the edge of the maze. You can take a look at the full commented Basic code for Telengard on my web site along with a VB.NET program that allows you to browse the maze. http://www.atarihq.com/danb/Telengard.shtml

Nice find. I used to be the Reference Librarian for my local Atari users group back in the early 80s and I got to see tons of newsletters from groups from all over the country. It's really a shame that more of these haven't found thier way on to the net since they where a really great resource. Dan

MAME always strives to support the most clean an accurate set of ROMS as possible. It's not uncommon for a new version of MAME to be looking for different ROMS then an older version. For example if it's discovered that a specific ROM was not dumped properly, and a correct dump is found, MAME will be updated to look for the checksum of the newer version of the ROM instead of the older one. Also also common that smaller ROMS, like the ones used to generate the color palette in a game were not used in older versions of MAME, but are now used in a newer version. There are a couple ways to see if a ROM has been updated. First MAME can check for you. Start it from the command line like this: mame -verifyroms This will verify any rom sets you have to be sure they are up to date. You can also use a tool like RomCenter to verify your ROMS. Dan

There's a couple I know of. There is the Digital Press store in Clifton NJ, and Next Level Videogames in Blackwood. Dan

My mother tells me that when they were planning on buying it for me, she said to my father, "he'll probably play with it for 2 weeks then loose interest". She was wrong about that one! I spend endless hours with that system, and it started me on the road to my current career as a computer programmer. Dan

My parents got me my first system, an Atari 800, back in the early 80's. I actually kept the packing list from the order, here's what we got with the prices: 800 16K Computer $679.00 810 Disc Drive $449.00 850 Interface $169.00 410 Recorder $76.00 Joystick $20.00 Video Easel $35.00 Star Raiders $60.00 Epson MX80FT Printer $559.00 Printer Cable $30.00 32K Expansion Board $159.00 Touch Typing $20.00 Atari Word Processor $159.00 Breakout with Paddles $43.00 Graphit $17.00 Statistics $20.00 Visicalc $169.00 Atari 800 dust cover $7.99 1 box floppy disks $36.00 My computer today has 1Gig of RAM (around $24.00), back then, that much memory would have cost $5,013,504.00 Today a DVDr can hold round 4.7G for around $0.30. Back then the same capacity in floppies would have cost $197,551.71 Today, Microsoft Excel $229.00, then Visicalc, $169.00.

Amp is the manufacturer of the connector, they were/are one of the biggest connector makers in the electronics business. It being part of the 2600 kiosk makes a lot of sense. Dan

Hard to tell if they are hand printed. The piece the labels are on is probably shrink tubing. It's possible the text was printed on the tubing first, then it was shrunk on. This would lead to the text being a little uneven. Dan

The connector is quite unusual, it looks very industrial from what I can see in the picture, reminds me of the type of connectors used in automobile wiring harnesses. It also looks like there are a bunch of jumper connections that loop back on that connector. If this cable was designed specifically for the device it was connecting to, these wouldn't be necessary since they would just do this on the PCB. This would lead me to believe that this cable connects to something that wasn't originally intended to be hooked to a computer, or at least to an Atari computer. Dan

I played around with the R: handler in Atari800WIn and was able to get it to work somewhat. I loaded up AMIS BBS in the emulator and once it was up and running I could telnet to my local machine and connect to the BBS. I don't know how to setup AMIS so I didn't get anything to productive back, but it was a start. I also tried this with the Carina BBS but it wouldn't accept a connection. Dan

Arguably you could say that the 7800's CPU is more powerful since the version of the 6502 the NES uses does not have the BCD math mode, where there 7800's does, but in most cases this wouldn't have a significant effect on performance. Dan

I think the local label regions are delimited by the non-local lables. Here is a chuck of code from one of the Galaxian source files as an example. DODX: stats a block and it has two locals 1$: and 2$:. DECRX: starts the next block, it has one local 1$. Dan DODX: ;X SHOULD STILL HAVE INDEX TO DYDX TABLE LDA DYDX(X) STA BTEMP ;SAVE FOR BIT TEST AND #7 LDX ANMAT0(Y) CPX #4 ;ARE WE STILL PEELING OFF BCC 1$ ;IF NOT, MAKE SHORT DX SWEEP LDX STRTY0(Y) CPX #0B0 BCS 1$ LDX FLTBND BEQ 1$ ;DONT MOVE SO FAST IF AT END GAME ASL ;MAKE BROADER SWEEP 1$: BIT BTEMP BMI DECRX ;MSB INDICATES VECTOR IN MINUS X DIRECTION CLC ADC HPOS0(Y) CMP #RBOUND ;SEE IF AT THE RIGHT BOUND OF SCREEN BCC 2$ JMP FLANDN 2$: STA HPOS0(Y) BCC DOGRFX ;UNCONDITIONALLY DO GRAPHICS ; DECRX: STA BTEMP ;SAVE SUBTRAHEND SEC LDA HPOS0(Y) SBC BTEMP CMP #LBOUND ;IS LEFT BOUND ABOUT TO BE EXCEEDED? BCS 1$ JMP FLANDN 1$: STA HPOS0(Y);ELSE RECORD IT ; DOGRFX: JSR STUFEX

Here is his web site, you can see a list of the other games he worked on there. http://mysite.verizon.net/scottathome/index.html If you lookup the phone number that's in the readme.doc file, it's still his number! Dan

The artifacts only show up when you plot single pixels horizontally. If you put two or more pixels next to each other a line you won't get artifacting. Dan

There are some great documents on that site. I found the Centipede notes that where just put up pretty interesting. It contains a bunch of documents discussing the results of prototype play testing. It's interesting that a lot of people didn't like the trackball control and Atari even tried a full size trackball to see if people would like that better. Dan

How did you identify the cabaret Pac-man!? I would have had no clue on that one. Dam

Sounds like you are programming for the 5200/8-bits not the 7800. You might want to ask over in the 5200 programming forum. Dan

What exactly does it do when you power it up? Do you get anything on the TV or just snow? Dan

The schematics on this page: http://www.jsobola.republika.pl/schematy.htm refer to this as a test connector. These schematics are not official so we can't be sure why it was labeled that way, but where it connects to in the circuit seems to bear this out. For example there is a pin that connects to the power adapter jack, but no pin that connects to the regulated power. If the connector was intended for an add on it would probably have a connection to the regulated power. Dan

Yeah, the numbers on the chips aren't readable in that pic, but I dug out one of my 7800's: The major chips are Left side CO25349-30 (MARIA) - Handles graphics in 7800 mode, and clock generation and address decoding in both modes. CO14806C-29 (CPU) - Atari's version of the 6502 CPU Middle column 6116L-5 (RAM) - 2K x 8bit static RAM, only used in 7800 mode 6116L-5 (RAM) - 2K x 8bit static RAM, only used in 7800 mode BIOS ROM - Used for boot up CO10444D-01 (TIA) - Graphics in 2600 mode, Sound and fire buttons in both modes 6532 (RIOT) - RAM and Timer in 2600 mode, Joystick direction, difficulty switches, pause, select, and reset switched in both modes. Dan