DanBoris' Tech Blog

I wonder if the horizontal ball control evolved somehow during the course of the design? The circuit I described seems simpler and more straightforward than the one Atari actually used, but perhaps it took people awhile to figure out exactly how they wanted the speedups to behave? If they started out with a more complex sequence of speedups and then simplified it, it may be that the complex circuitry had been needed earlier but wasn't in the end.

I wonder if the horizontal ball control evolved somehow during the course of the design? The circuit I described seems simpler and more straightforward than the one Atari actually used, but perhaps it took people awhile to figure out exactly how they wanted the speedups to behave? If they started out with a more complex sequence of speedups and then simplified it, it may be that the complex circuitry had been needed earlier but wasn't in the end.

 

Another thing to consider is that there are no AND nor OR gates in the Pong circuit (but a lot of NANDs and NORs). If they were striving to keep the number of different chips down they would have had to add some inverters which would add at least one more chip. Also the inverted versions of V1, V2 and V4 aren't available so that may require yet another inverter chip to get these.

 

Given what was available in the way of signals and chips, the original circuit was probably the most straight forward even thought it may have saved a chip of two.

 

I would love to see schematics for some other Pong like game by either Atari or other companies to see different approaches to implementing the game.

 

Dan

Another thing to consider is that there are no AND nor OR gates in the Pong circuit (but a lot of NANDs and NORs). If they were striving to keep the number of different chips down they would have had to add some inverters which would add at least one more chip. Also the inverted versions of V1, V2 and V4 aren't available so that may require yet another inverter chip to get these.

 

I did offer an alternative which replaced the ORs with NANDs and didn't need inverted /V2 and /V4, but did require inverting the counter (or else using a different counter which goes down instead of up). Not sure what counters were available.

 

BTW, I wonder how the layout was done? Is Pong a double-sided PCB?

BTW, I wonder how the layout was done? Is Pong a double-sided PCB?

 

Yes, Pong is a double sided PCB. I am going to guess that the lPCB ayout was done manually.

 

Dan