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Topic: Classic 70's TV game reproduced on the Arduino/AMTEGA328 (Read 8 times) previous topic - next topic

zx80nut

Hi.
I've modified the code and schematic to check for the value on pin 6 (PD4) of the ATMEGA328 (ie. ARDUINO DIGITAL PIN 4) at startup.
If it is low then the chip now displays using NTSC timing. Leave disconnected for PAL.

Currently, it uses information that I took from the datasheets. I am waiting for an AY-3-8500-1 NTSC version of the original chip to arrive. When I get it, I will tweak values if necessary.

Latest code and schematics online.
http://searle.hostei.com/grant/AVRPong/index.html



Any probs or queries, please feel free to contact me.

Grant
http://searle.hostei.com/grant/

DirtBiker

Sorry it's taken me so long to get back to you Grant.  Life got busy.

I tried your new code and it works great!

I was talking to a friend of mind that owns a small business making stuff for Arduinos.  He thought he might like to make a shield that accommodates this game.  Would you have an issue with this?

My next step in this is to build mine into a glass-top table and re-arrange the graphics slightly to make a '70s era bar video game.  Should be a great way to quaff a few pints of Guinness.  I know I spent a lot of time, money and my liver playing those bar games circa 1974 when I bought my Yamaha RD350.

Those were the days... bikes, bars and broa..err, ladies!.

Dirt Biker

zx80nut

#22
Sep 01, 2013, 12:49 am Last Edit: Sep 01, 2013, 01:19 am by zx80nut Reason: 1
Hi DirtBiker.

Glad it's working for you.
Yeah, your friend is free to make a shield or whatever - glad it's of use. Obviously, no charging for my code, and a link to my original page please :)

I received the NTSC (AY-3-8500-1) version of the chip yesterday. I've been so busy at the moment that I haven't tried it yet, so hopefully in a few days power it up and I'll super-impose the original and my versions to see if any values need tweaking. I'll update when ready.

On free web hosting, so unfortunately sometimes the server is unavailable. If there is a problem loading any of my pages then please try again in a while/next day.

All the best.

Grant

DirtBiker

Dirt Biker

zx80nut

Hi.
The original NTSC version of the chip (AY-3-8500-1) arrived safely from the US. I connected it up and it works, so I was able to to an accurate side-by-side comparison between my implementation and the oritinal NTSC chip. I have now updated the code so that it accurately implements the NTSC version as well as the PAL versions.

Differences between the NTSC and PAL versions...
1. The scores on the NTSC version occupy 20 scanlines (4 lines per block) but the PAL version occupies 30 scanlines (6 lines per block) - as on the datasheets. The NTSC numbers are noticeably shorter.
2. The vertical net/centre line on the NTSC version is SOLID but the PAL version is DOTTED (as can be seen on the pictures below).
3. The NTSC picture has fewer scanlines, so a lower vertical resolution. This results in the ball appearing to travel at slightly steeper angles on the NTSC version because each step therefore has a larger Y displacement. Additionally, this lower resolution makes the bats appear longer.

Here are actual screenshots of the PAL (left) and NTSC (right) versions as created with my code (these match the actual original chips)...


Updated code and descriptions on my web page here...
http://searle.hostei.com/grant/AVRPong/index.html

Any queries, as always, feel free to ask.

Regards.

Grant
http://searle.hostei.com/grant/index.html


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