5 replies to this topic

[JAC!]

Hi,

I think I remember something. But maybe it also was a dream I once had. It was about a 13 bit counter and NTSC which was cheap/easy to implement and resulted in 8192/60 Hz = 2:16 minutes. Enough time for the gamer to think it was worth to spend the coin and short enough for the owner of the tavern to have many gamers.

Was it a dream? I have spent many years with 6502 coding, so I wouldn't even wonder about my dreams being so accurate in terms of bits and frames

Peter/JAC!

[SEgamer]

According to some MAME documentation, a "Timer Mode 0" was used to assign the timer to a 13 bit counter for the 8051 microprocessor, which I guess was used or maybe a similar one was used in a lot of arcade machines.

[Chris++]

You might be thinking of Combat and several other early VCS games that involve scoring as high as possible before each game just ends abruptly. These were each 2:16 in duration.

[JAC!]

Hi Chris,

Yeah, that's where it originates from! I check the code of early Atari and Activision games. They all use a 6 bit counter which counts "almost seconds" (64/60Hz) and a 7 bit counter for the overall game time. This way two "INC", an "AND" and two branches can to the whole job. Once again a nice example of sacrificing game elements/logic ('Why the hell "2:16" and not "2:00"?') for ROM space.

Thanks, Peter.

[JAC!]

Thanks to d-wilson for pointing me to the original location where I read it 2 years ago.
It was the answer given by Joe Decuir, the creator of Combat, himself in this thread!

The question has two parts:
- why have a time limit?
- why this number?

Having a time limit at all applies to some games but not others. E.g. Video Olympics will end on score = 21.
Some games end when the player uses up too many resources, or achieves some goal.
Some games (like Combat) could go on indefinitely, or until a certain amount of damage was taken.

This is a port of common Arcade (coin-op) logic.
These machines generated 60 frames/second. 8192 (2^13) frames is just over 136 seconds, or 2:16.
Some arcade game probably used a binary 13 bit counter, and the practice followed.
(The early arcade games were made with hardwired logic, not microprocessors.)

2:16 is long enough to have fun without being exhausting.
Sometimes there would be others waiting their turn to play.
Plus, the Arcade operator would want more quarters...
In the case of a home machine, it doesn't overtax a parent's patience.
'Mom, wait until I finish this game.'

Yours,

Joe Decuir
Atari 1975-1979
Amiga 1982-1984

...

Hi,
The value was developed by the coin-op designers.
They in turn listened to their customers.
The value is 2^13 TV frames (60 Hz).
In the original arcade machines, it was a hardware timer, not microprocessor firmware.

If the value is too short, it will annoy the end-customers (and miss their quarters).
If the value is too long, the operators (who want more quarters), the next people in line (who want to play) or the girlfriends (who are bored and want attention) will complain.

We just recycled their experience in the home systems.
We didn't realize (in the first generation) that we needed levels.
As Nolan told us: "the best games are easy to learn and difficult to master".

Joe Decuir

[M.A.M.E Offender]

Fascinating analogy.