Pole Position Free Play w/attract mode

The whole passing eprom data back and forth, waiting for reply, having to understand and clarify what happened...really more effective if someone just lent me a boardset. But for some reason, people are uncomfortable with this idea.

@#$%!

Mark. Please confirm your address and I can send you a P.P. boardset that's been in the box since Dick Milikan repaired and sent it back to me 3 years ago. (Are there any other P.P. parts you need for this)?

Darren Harris
Staten Island, New York.
 
After you get it working on PP1 ..will you be adapting this mod for PP2?
 
I did today :)

Chip 136014.103 and 136014.104 contain instructions and data split across them. To my surprise, GAME OVER was actually stored as raw text across the two chips (meaning there must be a routine that takes raw text and converts it to characters made up of a combination of graphic blocks).

In EPROM 103 at location $0392: 41 45 4F 45 ; A E O E
In EPROM 104 at location $0392: 47 4D 20 56 52 ; G M V R

Simply change these values to spaces (20):

103: $0392: 20 20 20 20 ; four spaces
104: $0392: 20 20 20 20 20 ; five spaces

And viola! No more "GAME OVER" in demo mode. Oh, and of course we need to fix up the checksums:
103: $1FFF: 7A
104: $1FFF: 44

Or people could have fun with the nine characters and put "FREE PLAY" or whatever they like; calculating the checksum would be an exercise for the reader.

I'm not sure if there are any real differences in the Ver1 and Ver2 ROMsets... but I finally got around to doing this on my PP1 (ver2) ROMs and I had to do the checksums differently. The checksums for both of those files was FF and to get them balanced I had to edit one of the NOOPs before that last section of nothings (FF)... as I couldn't get the FF's to balance out with just editing one of them.

The GAME OVER text is stored in the same areas as what is says above.

203: $1FA6: 9A
204: $1FA6: BC
 
Got the boards from Darren the other day. After I pulled out the boards I didn't have much hope that they'd be running, between the corrosion and dirt on the chips, the condition of the edge connector, and the large gouge that was in the box.

However, in spite of all that, I made up a quick Jamma harness to test it out. I fired it up in my Jamma cabinet and received a big "RAM 6" error, so I took the board over to my mini-Jamma test rig where I could more accurately dial in the +5VDC.

Lo and behold, it runs! Temperamental at times (didn't realize how flaky these boardsets are); hopefully it can hold out long enough that I can make some progress on the freeplay hack.

However, looks like this boardset is running Pole Position version 2, and I had only applied my hack to version 1. Should take me a few days next week to apply the hack to version 2 and then I'll burns some EPROMs and see where I get on actual hardware.
 
Lo and behold, it runs! Temperamental at times (didn't realize how flaky these boardsets are); hopefully it can hold out long enough that I can make some progress on the freeplay hack.

They are amazingly flaky... I've dragged my machine all over the room it's in with no problems... but I touched the boards for 5 minutes to swap out those ROMs to remove "GAME OVER" and it took me 45 minutes to get them working again (stopped reading my gas pedal). Beat, hump, burn, maim the cabinet... it'll be fine... but fart on the boards and you just got yourself a RAM error, or input stops working, or you lose the voices... music... engine, tire squeal, etc. lol

That's why I said if you were local I'd have no problem bringing my boards over. ... but shipping them? The last time I saw balls that big the were rolling behind Indiana Jones while he was running out of the cave with that gold idol. Darren, can you even wear standard pants or to you have to get everything custom made?
 
They are amazingly flaky... I've dragged my machine all over the room it's in with no problems... but I touched the boards for 5 minutes to swap out those ROMs to remove "GAME OVER" and it took me 45 minutes to get them working again (stopped reading my gas pedal). Beat, hump, burn, maim the cabinet... it'll be fine... but fart on the boards and you just got yourself a RAM error, or input stops working, or you lose the voices... music... engine, tire squeal, etc. lol

That's why I said if you were local I'd have no problem bringing my boards over. ... but shipping them? The last time I saw balls that big the were rolling behind Indiana Jones while he was running out of the cave with that gold idol. Darren, can you even wear standard pants or to you have to get everything custom made?

That reminds me. I have to get my world records back on Indiana Jones. :D I have higher scores recorded, but there is nothing like doing it live.

Yeah, I knew it was a risk. I think the Post Office X-rays the boxes and then plays football with any that have printed circuit boards on their lunch breaks.

If the game is working I assume it is not a good idea to pull and clean all the chips, correct?

For myself Free Play w/attract mode is not a big deal. I could just rig up a button at the coin door lock.

But if I could flip a switch and make the "Game Over" letters black instead of the white that burns the hell out of the monitor phosphors that would be great. :-D (Something like that for the Star Wars Death Star explosion would be just as great).

Also, a good way to switch between two P.P. boardsets int hes same cabinet, so that when you mess up early you don't have to wait forever for the timer to run out before starting another game. (I know there is a reset switch, but is that a good idea?).

Darren Harris
Staten Island, New York.
 
I forgot to ask.

Can someone explain the differences between Pole Position version 1 and Pole Position version 2?

Also, what is the normal variance from +5VDC on these boardsets and recommended target range?

Thanks.

Darren Harris
Staten Island, New York.
 
I forgot to ask.

Can someone explain the differences between Pole Position version 1 and Pole Position version 2?

Also, what is the normal variance from +5VDC on these boardsets and recommended target range?

Thanks.

Darren Harris
Staten Island, New York.


http://therealbobroberts.net/pp2.html <-Conversion information.

I measure +5 on the boards at any of the chips towards the mid-bottom of the board. I'll adjust that to +5V, then check the other board and make sure that's close as well... if the other board isn't over that +5V that I set on the first board, I'll bump the first board's +5V up to about 5.15V or so. Just so there a little room to play with.

It should be noted, maybe, that I've converted my PP over to a switching power supply for the +5's though, so I don't have to deal with any sense circuit or anything like that. But, I am still feeding the +5 through the edge connector and not directly to the board.

EDIT: I went back and re-read that, and noticed that you said VERSION... sooooo... derp. Anywho, leaving that link up either way. As far as game play goes, I doubt there are any major differences. It's not like Tron where Version 1 is easy mode with annoying block sounds on the MCP levels, and version 2 and 3 are pretty much the same. Probably just some minor code re-writes and cleaning?
 
Last edited:
Pole Position version 2 patched; most of the original patch applied just fine, but version 2 required that I move two of the addresses. Figured it out. Looks and works awesome in MAME. I'll burn the EPROMs this weekend and give it a try. Crossing fingers it works on this hardware (and that this hardware works with the software :))
 
Weekly update:

So, as other testers have reported, it does not work on the actual hardware. Shifting does not start the game. I have made a 'debug' eprom that will print the value of certain memory locations to the screen so I can see the values in real-time and can validate which assumption I have wrong (ie find where the emulator is 'cheating'). Once I figure out where the 'lie' is, I can start working around it (hopefully).
 
Weekly update:

Debug EPROM shows a different value on the screen on real hardware vs MAME, so something is not being emulated correctly. My MAME version is a little outdated, so I'm going to upgrade my MAME build to see if the emulation has improved. Then I'll try some new potential memory locations to output via my debug EPROM and hopefully spot the true input port values.
 
Update:

I'm convinced at this point that MAME does not correctly emulate the 51xx chip, and that the inputs are not actually passed through when the 51xx chip is in "credits" mode. So that throws the freeplay hack out the window. I'm going to try one more thing and see if the gas pedal input does get passed through during credit mode. I've already hacked up a version of the code to start the game with the gas pedal instead and will burn the EPROMs and test out this weekend.

If that fails, I'd be willing to pass on the work to someone else as I've invested too much time on this project and have many others that need attention. Maybe the guys working on the Pole Position replacement might have some insight on how to make it work if this fails.
 
Update:

I was able to successfully get the freeplay hack to work with the accelerator on a test bench.

Now I need a tester to whom I can send the EPROM patch to and have them test on a real machine. The pedal, when emulated, gives out an output of 00 to FF, but that's for a ideal/perfect potentiometer; I suspect on real games the upper and lower boundaries could be quite different. I have the "acknowledge" point currently set at 60, so want to make sure that's a good average setting. If not, I can tweak it slightly.

Prior to this I had "SHIFT TO START" flashing on the screen. Recommendations what the instruction should be now?

ACCEL TO START

or

PRESS ACCELERATOR TO START

or

??

vote now!
 
Back
Top Bottom