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Interest check - Pac-man Arcade for the 5200


tep392

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Here's a question for those of you who are playing it on hardware. The original Ms. Pac-man code uses a calibration method for the joysticks that differs from what I have implemented.

 

I have defined fixed thresholds for up,down, left and right. If you move off center and past the threshold, Pac will go in that directtion. The potential problem is that if the center of the joystick is off far enough, it might affect controlability. For example, if left/right is off to the right, you might have to move it far right to go right and only slightly left to go left.

 

The Atari Ms. Pac-man code does this differently. It defines min, max and center values for each axis and calibrates them as the game is played. The initial values are less than the true min and max the joystick is capable of. The first time you push the stick all the way right, it will save that value as the new max right value. It will then recalculate the center value as (leftmax+rightmax)/2. This leads to some odd control behavior until you have moved the joystick to it's limits in each axis. After that, everything is fine. This seems like a good method because it will auto calibrate for each joystick. The only negative is the odd control when you first start a game. For instance, you start a game by pushing right, and when you center the stick, Pac moves left because left hasn't been calibrated yet. I hope I'm making sense.

 

So my question for you is, have you noticed this odd control behavior when you first start up Ms. Pacman, and if you have, is it a nusance. I would like to use the Ms. Pacman method because it should work best since center will be true center after the calibration is finished. What do you all think?

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I tried playing around with the controls when the game first starts and as far as I can tell there doesn't seem to be a problem. I'm using a cx52 controller as apposed to an aftermarket one or an redemption type adapter. I was also playing it a bit with a sega controller with the Redemption adapter and I didn't notice any problems. I'll do some more testing later today.

 

There is an article about the recalibration code for the controller you mentioned above on Curt Vendal's site titled

Atari 5200 "Pam" Package Technical Documents Manual

 

 

Allan

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Here's a question for those of you who are playing it on hardware. The original Ms. Pac-man code uses a calibration method for the joysticks that differs from what I have implemented.

 

I have defined fixed thresholds for up,down, left and right. If you move off center and past the threshold, Pac will go in that directtion. The potential problem is that if the center of the joystick is off far enough, it might affect controlability. For example, if left/right is off to the right, you might have to move it far right to go right and only slightly left to go left.

 

The Atari Ms. Pac-man code does this differently. It defines min, max and center values for each axis and calibrates them as the game is played. The initial values are less than the true min and max the joystick is capable of. The first time you push the stick all the way right, it will save that value as the new max right value. It will then recalculate the center value as (leftmax+rightmax)/2. This leads to some odd control behavior until you have moved the joystick to it's limits in each axis. After that, everything is fine. This seems like a good method because it will auto calibrate for each joystick. The only negative is the odd control when you first start a game. For instance, you start a game by pushing right, and when you center the stick, Pac moves left because left hasn't been calibrated yet. I hope I'm making sense.

 

So my question for you is, have you noticed this odd control behavior when you first start up Ms. Pacman, and if you have, is it a nusance. I would like to use the Ms. Pacman method because it should work best since center will be true center after the calibration is finished. What do you all think?

 

Well don't do it like Ms.Pacman. It causes trouble when using digital converters (like the masterplay interface).

You have to start a game move the stick around in all directions for a few seconds before it starts to work right.

Then reset and start a new game cause a ghost normally gets you during this. :)

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Here's a question for those of you who are playing it on hardware. The original Ms. Pac-man code uses a calibration method for the joysticks that differs from what I have implemented.

 

I have defined fixed thresholds for up,down, left and right. If you move off center and past the threshold, Pac will go in that directtion. The potential problem is that if the center of the joystick is off far enough, it might affect controlability. For example, if left/right is off to the right, you might have to move it far right to go right and only slightly left to go left.

 

The Atari Ms. Pac-man code does this differently. It defines min, max and center values for each axis and calibrates them as the game is played. The initial values are less than the true min and max the joystick is capable of. The first time you push the stick all the way right, it will save that value as the new max right value. It will then recalculate the center value as (leftmax+rightmax)/2. This leads to some odd control behavior until you have moved the joystick to it's limits in each axis. After that, everything is fine. This seems like a good method because it will auto calibrate for each joystick. The only negative is the odd control when you first start a game. For instance, you start a game by pushing right, and when you center the stick, Pac moves left because left hasn't been calibrated yet. I hope I'm making sense.

 

So my question for you is, have you noticed this odd control behavior when you first start up Ms. Pacman, and if you have, is it a nusance. I would like to use the Ms. Pacman method because it should work best since center will be true center after the calibration is finished. What do you all think?

 

Well don't do it like Ms.Pacman. It causes trouble when using digital converters (like the masterplay interface).

You have to start a game move the stick around in all directions for a few seconds before it starts to work right.

Then reset and start a new game cause a ghost normally gets you during this. :)

 

Yes, this is what I was noticing when running in emulation. I started with the Ms. Pac-man code but changed to what I have now because of that issue. The problem with what I have now is that I have to make the center deadband fairly wide so Pac won't change directions with the stick "centered", which could make the control feel loose.

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Personally, I don't think there is any reason to have analog stick calibration code in a game like Pac-man. Just do it like many other games:

 

vertmove

lda SPOT1

lsr			 ;divide by 2 to prevent overflow
cmp #$1A ; stick pulled up
bmi mvup
cmp #$50 ; stick pulled down
bpl mvdown

rts

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So exactly how is this different from regular 5200 Pac Man? If there are some good improvements, I will buy.

 

You know how 2600 Ms. Pacman was hacked into Pacman? Well this is kind of the same, but it's 5200 Ms. Pac hacked into Pacman. :)

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Personally, I don't think there is any reason to have analog stick calibration code in a game like Pac-man. Just do it like many other games:

 

vertmove

lda SPOT1

lsr			 ;divide by 2 to prevent overflow
cmp #$1A ; stick pulled up
bmi mvup
cmp #$50 ; stick pulled down
bpl mvdown

rts

 

This is what I'm currently doing. Saw it in some adventure type game. :)

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I've been noting everyone who's asked here or PM'd me. I have enough parts to make 20 carts and that will cover everyone who's asked. Assuming I can continue to get parts, I'll keep making batches periodically, so don't worry if you miss out on the first batch.

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I've been noting everyone who's asked here or PM'd me. I have enough parts to make 20 carts and that will cover everyone who's asked. Assuming I can continue to get parts, I'll keep making batches periodically, so don't worry if you miss out on the first batch.

 

Just had a chance to try the demo. Works great with both analog controls and digital using a masterplay interface.

Very very good game. As usual, I enjoyed it much more on the 5200 than the a8.

I hope you release a full version BIN for multicarts. I would even be willing to spend a few bucks on the BIN file....

If you consider doing it that way....

 

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I've been noting everyone who's asked here or PM'd me. I have enough parts to make 20 carts and that will cover everyone who's asked. Assuming I can continue to get parts, I'll keep making batches periodically, so don't worry if you miss out on the first batch.

Good, I'll like to get one too. I've just bought a new Jag game.

Edited by walter_J64bit
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I bought it with non-functioning controllers, hoping the fix would be simple. Turns out they just needed the contacts cleaned off. One has copper traces which were heavily tarnished and the other has aluminum (I think) that were also oxidized. They aluminum cleaned up with a pencil eraser and the copper required some fine metal polish. Both work great now.

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