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Posts posted by playsoft

  1. The i/o pins can't be configured like the 2600/7800/A8 but I don't know if you could make use of the POT common line?


    This is controlled by software and is normally enabled at initialisation and never touched again. As far as I know the only reason for it to be software controllable is for trak-ball detection; if you read the POTs without enabling POT common you get different values from a joystick and a trak-ball.


    You usually read the joystick once per frame. You read the POTn registers and store their values in RAM. You then write to POTGO to start another POKEY POT scan.


    I wonder if disabling POT common for a few cycles then enabling it before writing to POTGO could be used to signal a rumble request? I don't think this would affect a standard joystick as POT common is enabled before the POKEY POT scan is started. With your USB interface, if you can trigger an interrupt on the POT common line, then when you see it go from high to low that is a rumble request.



    • Like 1

  2. 1 hour ago, glurk said:

    Thanks Paul.  I wasn't even going to ask you.  I've never owned a 5200 and don't even especially like them.  :)


    I looked at the conversion reference, and I won't be doing one.  In fact, I've already started work on something new.  But if another programmer actually wants to convert this, I don't think it would be an enormous effort.  So if someone is serious about taking that on, I'll make my source code available to them.


    For now, I'm going to be using the knowledge I've gained from this one to (maybe) work on another new game!

    Well, I did end up giving it a quick go and it did convert easily.


    The only issue I had was a start up race condition. A routine at $AB47 is called which enables the VBI. Then a routine at $A701 is called which sets the vertical position of the plane. Should the VBI get in before the $A701 routine you end up with an extra image of the plane at the top of the screen. I got around this by syncing to the top of the screen before passing control to your code.


    It seems to play correctly, I used * & # for select and option.


    • Like 2
    • Thanks 4

  3. On 11/22/2021 at 11:31 PM, BIGHMW said:

    A would-be 5200 conversion would utilize the * key for the barn clearance, the # key for the amount of geese spawn, and the "0" key to select level, the bottom fire button would be the throttle while the stick moves up or down. Paul Lay (a.k.a. @playsoft) can do the conversion while @glurk would retain full rights. I know I have both an XEGS and a 5200 but Big Sexy enthusiasts would dig this game as much as I do. @glurk would you be OK with a conversion of this???

    @BIGHMW I have moved on from the 5200, so it's not for me. I would appreciate it if you would stop mentioning me whenever you ask for a 5200 port since it puts me in an awkward position.


    @glurk if you are interested in doing a 5200 port there is @ClausB's guide from ANALOG Computing, Transporting Atari Computer Programs to the 5200. Also @phaeron's Altirra Hardware Reference Manual. If it is something you decide to go ahead with and have any questions please feel free to PM me.



    • Like 5

  4. What the Atarimax Ultimate SD provides is:


    (1) An interface to read data from files on the SD card into the ROM area.


    Although I used .hyb/.dat pairs in AtariBlast! and the other demos, there is no reason why you couldn't use a .bin file and read from many different files.


    There is one significant restriction in that you must disable the ROM before you update it. So your code must be running from 5200 RAM as must be any graphics data displayed (alternatively disable the screen).


    (2) An interface to write data from the ROM area to files on the SD card.


    For this to be of use you do need to use the .hyb format, since you need to be able to change what's in the ROM area.


    Being able to read and write files on the SD card gives you the ability to store high score tables, save states and say, load/save pictures with a 5200 paint program, the sort of things you can do on an A8 with a disk drive.


    (3) Although I don't know them, there must be interfaces for reading and traversing the directories on the SD card, since the Atarimax menu program has this functionality.


    (4) The hybrid format which is the Atarimax's own bank switching scheme. Hybrid files must be 512K and have the .hyb file extension.


    The cart area is split so that $4000..$7FFF is banked and $8000..$BFFF is fixed.


    There is one range of bank switch registers which allow you to select 16K banks in the $4000..$7FFF area, standard 16K bank switching functionality.


    There is another range of bank switch registers which allow you to select 8K banks, with $4000..$5FFF providing write access and $6000..$7FFF providing read access to that 8K bank. There are more details here:




    While this effectively provides additional RAM, it's main use is for writing data to the SD card rather than porting A8 games because of the restrictions associated with it. 

  5. 14 hours ago, BIGHMW said:

    Wouldn't it be more feasible if AtariMax offered downloadable firmware upgrades so that 8-bit files, in .xex, .car, or .rom, can also work provided they can be operated on the maximum 16K of RAM??? You would think that they would work.

    I wouldn't! I would think if it were feasible it would have been done by now (and as a PC app rather than embedded firmware on a SD cart).

    14 hours ago, BIGHMW said:

    But also, is it possible, that certain 8-bit titles, that work within the 16K RAM, but, have more than 32K ROM, can be recoded to a .hyb file that we know the AtariMax supports also??? This can open the door for TONS of more 8-bit titles for all of US 5200 owners to enjoy as well so that we won't need to get an XEGS (like I had to last year) just to play THOSE???

    You don't need the .hyb format for that. @Wrathchild has been doing this for years, converting such titles as Dropzone using the bank switching scheme from M.U.L.E. which can be produced as a physical cart or run on the Atarimax Ultimate SD (it supports the M.U.L.E. format in 64K/128K/256K/512K variants). Conversions such as these are the most difficult things to do on the 5200, requiring a lot of time and dedication. It may take many years to do the conversion and get all the bugs sorted out, so I doubt he wants to do TONS of them for you.


    As a non-programmer the only A8 games you can state as definitely possible to convert to the 5200 are those which run on a 16K 400/600XL. Configure Altirra as either of these 16K machines and see if the game works. If not then you need a programmer to analyse the game. Unfortunately such analysis is not simple, having to look at all aspects where the game may need RAM (screen buffers, character sets, P/M graphics, variables,  self modifying code etc.) which is why such questions aren't normally answered with any authority.

    • Like 1

  6. On 10/14/2021 at 7:14 PM, Giles N said:

    But is this a game that couldn’t be put on an individual 5200-cart, even if had inbuilt extra mem., or is it ‘just’ that no-one produces such carts…?

    As Harvey mentioned, one of the A8 versions runs as a 8mbit/1024K cart. Had there been a 1024K cart for the 5200 I would have targeted that. As there wasn't, it was a choice of having less levels in a 512K cart or using the programming API in the Atarimax Ultimate SD to load the data off the SD card for each level individually.


    8 hours ago, Giles N said:

    And its good to see the different ROMs, so lonely, so forgotten and ignored, now reemerge from dark dusty digital shelves of long-unused AtariAge posts dwelling right there on the treshhold of collective retrogaming-amnesia… that very shrouded mist from which only the most hardy of retrogames have ever returned from.

    It had it's day in the sun and was enjoying it's retirement. Nothing wrong with that.

    • Like 1

  7. I'm not sure about the 5200 version of AtariBlast! posted earlier in this thread because it only seems to be a .hyb file, it should be a .hyb and a .dat file.


    The final 5200 version (with the updated music) can be downloaded from:




    More recently there was a thread about where to obtain 5200 homebrews and conversions. I posted a .zip file of everything I'd done which included AtariBlast!:




    What the 5200 needs is for someone to maintain an archive list/rom pack like @Trebor does for the 7800. I also vaguely remember there being plans for an AtariAge homebrew database at some point.

    • Like 1

  8. I've not done anything with the demo since it was originally posted, other than to include the music posted by Jaden and Synthpopalooza. I had planned to investigate what I could do for the expanding formation but ran out of time as I wanted to complete Runner Bear for the 2020 New Year Disk. After that I totally lost interest in 5200/A8 programming, it seemed to become a chore rather than a rewarding pastime. Later, Darryl got me interested in the 7800 after seeing what he had achieved with Popeye. I've enjoyed looking at different hardware and have started a couple of 7800 projects.


    • Like 2

  9. I did nearly everything in parallel by restricting the A8 to only using the first 16K as RAM and not using the O/S. Then it's the same with a few bits of conditional code to handle the controllers/keys differently.


    Scramble was released on the 5200 first because I'd spent a long time play testing/tuning parameters in NTSC to get to a point where I was reasonably happy with it. I'd not done any play testing in PAL, only sanity tests to make sure the graphics were OK and that it didn't crash. However the game felt very different under the slower PAL frame rate and I couldn't face going through all that play testing again so soon. I released the 5200 version (as it's NTSC only) and thought I would take a break and do something else, maybe return to do the PAL play testing at a later date if there was interest in an A8 version but unfortunately it didn't work out that way.


    • Like 5

  10. 3 hours ago, BIGHMW said:

    Yes, believe it when i say that while yes the analog joystick version of the 5200 edition of this XEGS staple works, the trak-ball hack (included below) has pretty much no response at all, both came in my complete set of 5200 ROMs for my Atarimax (and yes I DID pay for them) I picked up a couple of years ago, in which now makes the total of over 360 titles for Big Sexy. If there's anyone that can help correct the problem, I have attached both the joystick version (in which uses the analog technology of the stock controller) and the trak-ball version as well, the one that doesn't work.

    bughuntjoy.hyb 512 kB · 1 download bughuntgun.hyb 512 kB · 1 download bughuntball.hyb 512 kB · 1 download


    The forum search function can be useful when you have problems. Search for Bug Hunt (this forum, all words) and you would have quickly found:




    As @SoundGammon says, the trak-ball should be connected to the second port.


    I don't recall ever publicly releasing the light gun version.

    • Like 1

  11. 17 hours ago, BIGHMW said:

    Thanks @playsoft! So after looking through that and studying it does that mean even I, can port over A8 games to Big Sexy or is my education/skill level not good enough to do so, as I hate to ask others to have to do it for me, I have always wanted to be more self-sufficient. (I have developmental and psychiatric issues) There are plenty of A8 ports that'll work on the 5200, like Bug Attack, to name one, and quite a few others as well.


    I DO own a 65XE, and an XEGS (picked up in November and December respectively last year) as well as the 5200 (since 1983) as well. I also own a Dell Inspiron with Windows 7 Pro that I can (if necessary) transfer .xex, .car, .atr, and .rom files and convert them to .bin, .hyb, or .rom very easily.

    You would have to learn to program first but I think anyone can do that with study and practice. A lot of us here learnt programming when we were kids, writing in Atari BASIC initially, learning 6502 assembler and including some machine language routines in our BASIC programs, then finally writing programs completely in assembler.


    Obviously this took a number of years and as older adults we might not learn as easily as we did when we were young and your issues may not help. But it is a path you could follow, perhaps to start with spend a year or so learning Atari BASIC with the goal of writing a simple game and see how you get on with that, whether it is something you enjoy or not.


  12. Having found the code above I then looked for other updates to the velocity variables, hoping to find something that was applying gravity. I found this:


    8186	B9 27 DE	LDA $DE27,Y
    8189	85 64		STA $64
    818B	B9 36 DE	LDA $DE36,Y
    818E	85 62		STA $62
    8190	B9 3B DE	LDA $DE3B,Y
    8193	85 63		STA $63
    81F8	BD 8B 22	LDA $228B,X ; velocity (low) = velocity (low) + gravity (low)
    81FB	18		CLC
    81FC	65 64		ADC $64
    81FE	9D 8B 22	STA $228B,X
    8201	A9 00		LDA #$00
    8203	7D A4 22	ADC $22A4,X ; velocity (high)
    8206	30 10		BMI L8218
    8208	C5 62		CMP $62     ; compare with max velocity
    820A	F0 17		BEQ L8223
    820C	90 15		BCC L8223
    820E	A9 00		LDA #$00    ; reset velocity (low)
    8210	9D 8B 22	STA $228B,X
    8213	A5 62		LDA $62     ; set max velocity
    8215	4C 23 82	JMP L8223
    8218	C5 63		CMP $63     ; compare with min velocity
    821A	B0 07		BCS L8223
    821C	A9 00		LDA #$00    ; reset velocity (low)
    821E	9D 8B 22	STA $228B,X
    8221	A5 63		LDA $63     ; set min velocity
    8223	9D A4 22	STA $22A4,X ; set velocity (high)
    8226	BD 8B 22	LDA $228B,X
    8229	18		CLC
    822A	7D 40 22	ADC $2240,X
    822D	9D 40 22	STA $2240,X
    8230	BD 6D 01	LDA $016D,X
    8233	7D A4 22	ADC $22A4,X
    8236	9D 6D 01	STA $016D,X
    8239	4C 70 82	JMP L8270

    Which is using the following tables:

    LDE27: .BYTE $0C,$14,$1E,$26,$00 ; gravity (low)
    LDE36: .BYTE $04,$04,$04,$04,$02 ; max velocity (high)
    LDE3B: .BYTE $FC,$FC,$FC,$FC,$FD ; min velocity (high)

    So it should also be possible to hack gravity.

    • Like 1

  13. The second thing I did was to see where the code reads the trigger and follow the path from there. I got to this routine which seems to be applying the flap acceleration to the velocity. I've added comments for what I think is going on:

    BCBD	B5 D0		LDA $D0,X
    BCBF	C9 08		CMP #$08
    BCC1	F0 34		BEQ LBCF7
    BCC3	BC 59 22	LDY $2259,X ; get flap index
    BCC6	38		SEC
    BCC7	BD 8B 22	LDA $228B,X ; velocity (low) = velocity (low) - flap acceleration (low)
    BCCD	9D 8B 22	STA $228B,X
    BCD0	BD A4 22	LDA $22A4,X ; velocity (high) = velocity (high) - flap acceleration (high)
    BCD3	F9 31 DE	SBC LDE31,Y
    BCD6	9D A4 22	STA $22A4,X
    BCD9	BD 72 22	LDA $2272,X
    BCDC	D0 03		BNE LBCE1
    BCDE	DE 6D 01	DEC $016D,X
    BCE1	A9 01		LDA #$01
    BCE3	9D 60 23	STA $2360,X
    BCE6	9D 72 22	STA $2272,X
    BCE9	A9 00		LDA #$00
    BCEB	9D 4A 01	STA $014A,X
    BCEE	E0 02		CPX #$02    ; x < 2 indicates player
    BCF0	B0 05		BCS LBCF7
    BCF2	A9 12		LDA #$12    ; flap sfx
    BCF4	4C 85 D4	JMP LD485
    BCF7	60		RTS

    So it's using 2 tables for the flap acceleration:

    LDE2C: .BYTE $80,$00,$5A,$DC,$00 ; flap acceleration (low)
    LDE31: .BYTE $00,$01,$01,$01,$01 ; flap acceleration (high)

    It seems that the first 3 columns are for the enemies, the fourth is the player but don't know what the last column is used for.


    So it would seem possible to hack the code to adjust the flap power. In the attached I set the first 3 columns to a really small value which stops the enemies from flying. One interesting thing here is that during an egg level, if you just sit on a high platform and don't do much you often end up stuck on that level; everything is cleared but nothing happens other than the occasional pterry attack. This could well be a bug in the original game which doesn't normally manifest itself because things aren't dropping into the lava so much.


    • Like 1

  14. I should start by saying that I am not interested in the bounty since it's best not to mix hobby and money plus the VS mode would be too much work. For that I think you'd pretty much need to understand all of the existing code and I've only done that once from a disassembly with 2600 Miniature Golf, which is a 2K ROM and took me a year.


    The first thing I noticed with the Joust ROM image is that the last 8K at $E000 is identical to the preceding 8K at $C000. It could be a 24K cart with the last 8K mirrored. This might be useful as it would provide free space for any hacks without having to increase the cart size (although that doesn't really matter as it could become a 48K cart).


    It's always good to have an expert player test to make sure nothing is broken. Maybe you can test the attached which is simply the Joust ROM with the last 8K blanked out (other than the 6502 vectors). Hopefully this will play exactly as the original and will mean that the last 8K is available for hacks.



    • Like 2
    • Thanks 1

  15. On 7/13/2021 at 5:17 PM, phuzaxeman said:

    Great info!  Blowsub def feels smoother playing with the cx52. 


    Looks like a lot of work to do conversions with the extra memory challenges.  Is it possible to do future 5200 hardware memory mods? 


    I do have Chop Suey on the 5200 so that's cool.  I actually bought that game in the 80s and I believe it came from the Europe.


    Probably the best way to get another martial arts game on the 5200 would be someone finishing Black Belt.  Graphics look really neat and the concept is great.  Whomever started that game had a great vision.  It's unfortunate that it was incomplete.  Maybe someone will pick it up one day.


    Thanks for sharing 7800 Arkanoid.  I'll check it out.



    Yes, Chop Suey was published by English Software originally. That needs a 48K A8 so whoever ported it will have put some effort into doing it.


    I'm not a h/w guy so can't say how feasible a memory mod is. Probably the most basic would be to have 32K RAM at $4000..BFFF which is swapped out when a cart is present. The cart would need to be able to disable itself, so that you can copy the program from the cart into RAM. It would be nice if the unused address space between the chips could also be mapped to RAM as A8 games often make OS calls that require replacement routines when ported to the 5200.


    With regards to Black Belt I think it depends on what's missing/wrong. If there are bugs that the original programmer couldn't fix they will be difficult for someone else to. When adding new functionality it depends on how much of the code you need to understand. When porting a game to the 5200 you don't really need to understand how it works; you are looking at what is code and what is data, what can go in ROM and what needs to go in RAM. The only occasion I put the effort in to fully understand a disassembly was when porting VCS Miniature Golf to the A8/5200/SNES. It's only a 2K ROM but I spread that out over the course of a year, although I was learning how the VCS worked at the same time.



    • Like 1

  16. 15 hours ago, phuzaxeman said:

    Thanks for the details on Karateka.  Sounds like a big job.  Maybe Ninja or Bruce Lee would be easier?


    One of the reasons I like Blowsub is it has that Air Sea Battle feel but uses the analog sticks.  What makes the 5200 shine is the analog sticks.  And when everything is working right with the analog sticks, the sticks and keypad games give a different gaming experience.  Magical Fairy and Curling along with classics like Galaxian, Pole Position, Baseball, Centipede, Star Raiders all have that analog feel that makes the 5200 a different console than the normal 8bit. 


    Have you every played Arkanoid on the 8bit?  I think someone was working on updating or releasing a new 8bit version.  What kind work does it take to make a game play with analog controls like you did on Blowsub.  I'm not an expert but was wondering.

    Ninja needs a XL so probably not, although if it's just uncompressing itself into the extra memory you might be able to do something with a bank switching cart. Bruce Lee looks more promising but it would still be a lot of work. The only easy ones are those which run on an unexpanded 400 or 600XL.


    The CX52 joystick is really 2 paddle controllers so the code in Blowsub which reads the A8 paddles is also used to read the 5200 joystick. One thing I did in Blowsub for paddle control was to move the ship to the mid-point of the old and new positions first, so that it looked more like the ship was moving between them rather than instantly appearing at the new position.


    Sometimes for digital control with the CX52 I split the controller range into 9 zones, dead zone in the middle and 4 either side to give 4 different speeds depending on how far you move the joystick (try Scramble or Yars' Strike). I'm not sure it plays any better than when using a digital stick, but control with the CX52 seems smoother this way.


    I don't know about a new A8 Arkanoid but there is one in development for the 7800 which looks great: 7800 Arkanoid WIP



    • Like 1

  17. 13 hours ago, phuzaxeman said:

    Hey, I just played BlownSub for the first time and I really liked it. Fun game that has analog controls. Thanks for sharing. 


    Also, I just played Asteroids with the keypad and it's really awesome.  Thanks. 



    Quick question, and I'm not asking for anyone to port. But is it possible for 8bit Karateka to be ported to the 5200? The keypad controls would be pretty cool. Just wondering.  Wish there were more martial arts games.



    Thanks, out of them all Blowsub is my favourite.


    It's hard to say with Karateka. It is using mode E graphics, which is a bitmap mode and it keeps 2 screen buffers so that one is displayed while the other is drawn. This requires 12K RAM so that only leaves 4K on the 5200 for everything else. Even if that was enough RAM the A8 program is a 90K disk/128K cart so it would be quite an undertaking to try and disassemble and modify something of that size - it could well take longer than programming a new martial arts game from scratch.

    • Like 1

  18. 18 hours ago, darryl1970 said:

    I tried these on actual hardware, and it was actually decent. This was never a fun port for me. I didn't realize the asteroids were in slow mode though. I am pretty sure the original unfinished version calibrated the stick after rotating it in all directions. This is much better.


    I also thought the game was just dog-slow. This was actually pretty fun, and it felt like Asteroids. I was able to play well with the stock controller. (I didn't try the keypad version yet.)


    Great job and Thanks!

    It is still slow, taking 5 frames to do everything, so running at 12fps. I did wonder if improving the asteroid drawing routines would help but I think it splits the processing over those 5 frames so I don't think there's any easy way of speeding it up.

    • Like 1
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