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8-bit conversions

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I've not tried it on a real machine but the Bug Hunt cart seems to run on Altirra with just 16K RAM configured, which is promising for 5200 conversion. It's a 64K XEGS cart which means it contains 8 x 8K banks. Banks 0..6 are switchable in $8000..$9FFF and bank 7 permanently resides in $A000..$BFFF. The Atarimax Ultimate SD cart does not support this banking scheme exactly, but it does allow for switchable 16K banks in $4000..$7FFF and a permanent one in $8000..$BFFF. A quick look at the cart image and it appears that all the code is in bank 7 with the other banks containing data (although I've only checked a couple of them). The code looks really neat and tidy.

 

So I think there is a good chance of being able to convert Bug Hunt but it will require an Atarimax Ultimate SD cart, a cable to connect the light gun up to the 5200 and a CRT display for the light gun to work properly.

 

 

threshold only requires a 5200 ;)

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threshold only requires a 5200 ;)

 

But it needs 48K and reads data into RAM from disk... so you'd probably still need an Atarimax Ultimate SD if it was possible to port it.

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I've not tried it on a real machine but the Bug Hunt cart seems to run on Altirra with just 16K RAM configured, which is promising for 5200 conversion.

 

It looks like you may be right (just tried it in Altirra too). I'd never tried it myself before, I was just going off a list someone else had made up. It doesn't surprise me though, as Bug Hunt is a pretty simple game (no use of P/M's at all).

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It is only around 4K of code in total, the rest is all graphics data. It ported ok, turning it into an analogue joystick version. This for real hardware/Atarimax Ultimate SD only, it will not run under emulation (unzip bughuntjoy.zip to bughuntjoy.hyb and copy that to the SD card).

 

bughuntjoy.zip

source.zip

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A 32K cart in a 5200, combined with the in-built 16K RAM, is similar to 48K in an A8 except that only 16K is writeable. So some 48K A8 games can be ported, where they only need 16K of writeable memory. Such ports can be quite a lot of work though, since you need to reorganise the software so that the writeable areas are located in the 5200 RAM and the rest in the cart ROM.

 

I think it might just be the cassette version of Slime which needs 24K, the cart version seems to run ok in 16K. So it should be possible to convert and such A8 carts are generally quite easy to do because they already have the correct RAM/ROM split. I don't have either form of Trak-Ball nowadays though - I remember having an A8 one back in the day but I have no recollection of ever programming anything for it so I don't know what is involved.

 

A few years ago when I first became interested in revisiting the Atari again I did play around with an idea which did not pan out - a sort of scrolling Qix where you had to entrap things. I still want to revisit that (probably next year) and Trak-Ball control may well be what it needs.

 

Dr Venkman tested out a ROM of Slime on his 800XL a few days ago. It was very sluggish but it was due to having to use a Translator Disk because the game is for OS B. He said he later loaded Translator into a bank on his Ultimate 1MB upgrade and then it performed much better. The CX-22 Trak-Ball performed adequately but he did mention it could be due to the Trak-Ball requiring cleaning or perhaps the game mechanics are at fault because it operates differently than say Centipede or Millipede it terms of movement.

 

I'd say don't compress it, just blow it up to 32K, add your name as the converter - although I think you said you don't like that - and an AtariAge logo and bam, that should fill it up. :)

 

Dan Kramer has some notes about the CX-53 that he thinks might benefit home brewers and hackers but I think it mainly consists of hints about Trak-Ball movements. I have it in PDF somewhere. He really would like to see more Trak-Ball games on the 5200 for the CX-53 and so would I. :)

Edited by Lynxpro
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Bug Hunt and Crossbow will both run with as little 32K on the 8-bits. The other lightgun games, Barnyard Blaster and Crime Buster, both need at least 48K.

 

Another XE game that only needs 32K is Thunderfox... but that's not such a popular game on the system anyway.

 

That's crazy that Crossbow requires so little RAM compared to kraptastic Bug Hunt.

 

Question is, would enabling Trak-Ball tax the kernel/CPU more than the light gun?

 

As much as I'd like to see an XEGS Light Gun - or a converted Sega Phaser - hooked up to the 5200 [perhaps with a Y Cable with a DB9?], I'd much rather play Crossbow with a Trak-Ball. Not just because the Trak-Ball is so friggin' cool but also because the game could then be played on an LCD. The XEGS version - unlike the 7800 version - didn't have a joystick mode option to it if I recall correctly.

 

Compared to NES Hogan's Alley, Crime Busters looks pathetic.

 

It's too bad those Commodore 64 light gun games didn't get ported to A8…there'd be potentially more material to work with in getting over to the 5200… :)

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Dr Venkman tested out a ROM of Slime on his 800XL a few days ago. It was very sluggish but it was due to having to use a Translator Disk because the game is for OS B. He said he later loaded Translator into a bank on his Ultimate 1MB upgrade and then it performed much better. The CX-22 Trak-Ball performed adequately but he did mention it could be due to the Trak-Ball requiring cleaning or perhaps the game mechanics are at fault because it operates differently than say Centipede or Millipede it terms of movement.

 

I'd say don't compress it, just blow it up to 32K, add your name as the converter - although I think you said you don't like that - and an AtariAge logo and bam, that should fill it up. :)

 

Dan Kramer has some notes about the CX-53 that he thinks might benefit home brewers and hackers but I think it mainly consists of hints about Trak-Ball movements. I have it in PDF somewhere. He really would like to see more Trak-Ball games on the 5200 for the CX-53 and so would I. :)

 

Ignoring Trak-Ball support, Slime looks like it should be an easy port as it's a 16K cart and runs on a 16K machine. I would opt for a 32K image and use the extra 16K to provide the A8 functionality it requires.

 

From what I've been able to find out, programming the CX-53 is completely different to the CX-22. The A8 Trak-Ball connects to the joystick directional pins and for each axis you get two bits; one indicates the direction, the other toggles as the Trak-Ball moves and you have to monitor very closely so you don't miss anything. The 5200 Trak-Ball connects to the pots and it appears the value indicates both the direction and how fast it is moving. I may be wrong (I have neither) but that sounds like the 5200 Trak-Ball will have a lower cpu overhead.

 

I'm not going to attempt any Trak-Ball programming until I have one. If Best had them I'd order one today, but I'm reluctant to take a punt on eBay until I see one described as working.

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That's crazy that Crossbow requires so little RAM compared to kraptastic Bug Hunt.

 

Question is, would enabling Trak-Ball tax the kernel/CPU more than the light gun?

 

As much as I'd like to see an XEGS Light Gun - or a converted Sega Phaser - hooked up to the 5200 [perhaps with a Y Cable with a DB9?], I'd much rather play Crossbow with a Trak-Ball. Not just because the Trak-Ball is so friggin' cool but also because the game could then be played on an LCD. The XEGS version - unlike the 7800 version - didn't have a joystick mode option to it if I recall correctly.

 

Compared to NES Hogan's Alley, Crime Busters looks pathetic.

 

It's too bad those Commodore 64 light gun games didn't get ported to A8…there'd be potentially more material to work with in getting over to the 5200… :)

 

The main issue with the light gun is that the input is not hooked up on the 5200:

 

http://atariage.com/forums/topic/84254-crossbow-for-the-5200/?p=1025787

 

Bryan suggested reading the gun manually:

 

http://atariage.com/forums/topic/84254-crossbow-for-the-5200/?p=1028207

 

And that works, although you only get a resolution of about 20 positions horizontally as the 6502 is slow at counting compared to the speed of the electron beam. I modified Bug Hunt and disguised the horizontal coarseness a little by adding a small random offset. The result is OK, I didn't feel too frustrated by the inaccuracy but my ratings are consistently down compared to playing on the XEGS. Really the game needs modifying to be a bit more forgiving or, as you suggest, use a Trak-Ball instead.

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Ignoring Trak-Ball support, Slime looks like it should be an easy port as it's a 16K cart and runs on a 16K machine. I would opt for a 32K image and use the extra 16K to provide the A8 functionality it requires.

 

From what I've been able to find out, programming the CX-53 is completely different to the CX-22. The A8 Trak-Ball connects to the joystick directional pins and for each axis you get two bits; one indicates the direction, the other toggles as the Trak-Ball moves and you have to monitor very closely so you don't miss anything. The 5200 Trak-Ball connects to the pots and it appears the value indicates both the direction and how fast it is moving. I may be wrong (I have neither) but that sounds like the 5200 Trak-Ball will have a lower cpu overhead.

 

I'm not going to attempt any Trak-Ball programming until I have one. If Best had them I'd order one today, but I'm reluctant to take a punt on eBay until I see one described as working.

 

Wait… what are you lacking besides a CX-53 at your disposal? A 5200? An Atari 8-Bit computer? A CX-22 or CX-80? :)

 

Interesting that the cartridge version of Slime is 16K yet the Disk/Tape versions are 24K.

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Wait… what are you lacking besides a CX-53 at your disposal? A 5200? An Atari 8-Bit computer? A CX-22 or CX-80? :)

 

I have no balls :-o TRAK-BALLs that is :D

 

I have taken the plunge and ordered a CX-53 off ebay. When I brought the 5200 a couple of years ago, its journey over the Atlantic took 8 weeks and it arrived with two broken screws rattling around inside and required a little repair work. The shipping on the CX-53 is a couple of weeks and it looks a sturdy bit of kit, so hopefully I can play around with it next month.

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I have no balls :-o TRAK-BALLs that is :D

 

I have taken the plunge and ordered a CX-53 off ebay. When I brought the 5200 a couple of years ago, its journey over the Atlantic took 8 weeks and it arrived with two broken screws rattling around inside and required a little repair work. The shipping on the CX-53 is a couple of weeks and it looks a sturdy bit of kit, so hopefully I can play around with it next month.

 

You'll love it! The Trak-Ball makes the system worth owning. It's too bad it didn't get launched in the UK & Europe; Atari Inc probably would've shipped it with fixed controllers by then [just like how they shipped the 7800 with the JoyPads there instead of the ProLines we got here in North America].

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I may be wrong (I have neither) but that sounds like the 5200 Trak-Ball will have a lower cpu overhead.

 

Yes. The 5200 trak-ball is read just like the joystick. It looks like a potentiometer to the POKEY chip which does all the work. That's why it works so well with games that were written for the joystick as a proportional direction/velocity control. One thing it has that the joystick doesn't is a calibration line that can be used to calibrate the stationary readings even if someone is moving the trackball.

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Yes. The 5200 trak-ball is read just like the joystick. It looks like a potentiometer to the POKEY chip which does all the work. That's why it works so well with games that were written for the joystick as a proportional direction/velocity control. One thing it has that the joystick doesn't is a calibration line that can be used to calibrate the stationary readings even if someone is moving the trackball.

 

…yet not all joystick games work well with the 5200 Trak-Ball. The ones that did specifically were noted on the box with the Trak-Ball logo that AT&T ripped off the following year and has been known as the AT&T "Death Star" logo ever since.

Edited by Lynxpro

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You'll love it! The Trak-Ball makes the system worth owning. It's too bad it didn't get launched in the UK & Europe; Atari Inc probably would've shipped it with fixed controllers by then [just like how they shipped the 7800 with the JoyPads there instead of the ProLines we got here in North America].

 

It arrived today. I had high expectations and it doesn't disappoint at all. The trak-ball itself is really nice and the keypads feel solid and positive and work!

 

Also the eBay Global Shipping programme worked well for me. That the import duty is taken care of means I didn't have to pay any "handling fees" and I thought it was quick and cheap, certainly compared to what it cost me recently to send a package abroad via the Post Office/Parcel Force.

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Here is the previous Ultimate SD version of Bug Hunt modified for Trak-Ball control in port 2. You still need the joystick in port 1 to load it from the menu, but once running all control is via the Trak-Ball.

 

In calibration mode I get values of $72 and $75 for the two pots. When I release calibration mode and leave the ball stationary, I get readings of $6F..$70 and $72..$73 respectively. In the code here I take a pot reading, subtract the calibration value and divide by 4 to get the delta. This seems to work OK, it appears responsive and accurate enough when moving, stable when not. When I have some time I will study what the other 5200 trak-ball games do.

bughuntball.zip

source.zip

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Dr Venkman tested out a ROM of Slime on his 800XL a few days ago. It was very sluggish but it was due to having to use a Translator Disk because the game is for OS B. He said he later loaded Translator into a bank on his Ultimate 1MB upgrade and then it performed much better. The CX-22 Trak-Ball performed adequately but he did mention it could be due to the Trak-Ball requiring cleaning or perhaps the game mechanics are at fault because it operates differently than say Centipede or Millipede it terms of movement.

 

I'd say don't compress it, just blow it up to 32K, add your name as the converter - although I think you said you don't like that - and an AtariAge logo and bam, that should fill it up. :)

 

Dan Kramer has some notes about the CX-53 that he thinks might benefit home brewers and hackers but I think it mainly consists of hints about Trak-Ball movements. I have it in PDF somewhere. He really would like to see more Trak-Ball games on the 5200 for the CX-53 and so would I. :)

 

For what it's worth here's a port of Slime which will play with a joystick in port 1 and optionally the trak-ball in port 2.

 

Controls are:

 

start = start

pause = pause

reset = reset

* = select option

# = change value

1 = port 1 joystick control

2 = port 2 trak-ball control

9 = adjust trak-ball sensitivity

 

Note that you can only select the trak-ball if one was present in port 2 when the game started. Also when you do switch between joystick and trak-ball, the keypad switches instantly, e.g. you press 2 on the joystick keypad to select the trak-ball, you then press start on the trak-ball keypad to begin.

 

In this game the cursor is restricted to character sized movements, 4 pixels horizontally and 8 pixels vertically, so trak-ball control is not as fluid as it would be otherwise. I couldn't quite make my mind up about the sensitivity and there are two settings you can switch between by pressing 9. You probably won't notice much difference, I am not sure I do now.

 

Two interesting things from the port. The OS B restriction comes from using an interrupt service routine in the OS B ROM which comprises a single rti instruction. There was also a bug in one of the count down timer routines, which returned with a rti instead of a pla/rts. While the stack is ok the rti doesn't quite return to the same place a rts would, amazing it gets away with this on the A8.

 

That's me all trak-balled out for now but I would like to see Dan Kramer's notes if you can post them.

slime.bin

source.zip

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Here is Dan Kramer's trakball guide.

 

Allan

 

 

Thanks! Looks like I need to average the calibration and do it more often, but my divide by 4 was ok.

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Preppie_II_1983_Adventure_International_

 

 

Is it possible to modify the title screen similar to the first "Preppie!", where OPTION and SELECT were replaced with the corresponding * and # chars? (see attached)...

 

 

post-19655-0-90993900-1440941500_thumb.png

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