Posted by planetjay on January 12, 2002 at 14:45:01:
In Reply to: Newbie theoretical...updated posted by Dave on January 11, 2002 at 14:46:02:
There are 2 codes sent. One one key down. One on key up.
I found a really great document that tells you more than you ever wanted to know. Download it in Microsoft Word Format here.
: Yes that summarizes my question exactly... in the original game, the cpu can be told via hardware that buttons a,b,and c are pressed at the same time. With a keyboard hack or encoder, mame sees the presses come in serially. The question then becomes, is the serial entry of the 3 keypresses from an encoder into mame fast enough for the game rom to consider it "simulatanious"? If everyone could just fire up streetfighterII, play
: Zangeif, and try his clothesline spin by pressing the 3 punch buttons at the same time....I get about 50% success rate.
:
: : Note that most normal keyboard encoders are slower than those used in the I-pac, Hagstroms, etc. With the bandwidth limits of the keyboard port, you still will get some polls while the changes are still "in the pipe", but a lot less than with slower encoders.
: >I don't think the original poster was talking >>about ghosting, I think he was saying that on >an original game, the processor could just go >out and read all the inputs at once, whereas in >MAME, or with the keyboard or IPAC etc, the PC >will actually get the individual key presses >over the serial keyboard link, so that if you >press say
: >: : "a, b, and c" at the same time, on the >original arcade game, the processor would see >exactly that. On a keyboard or encoder, the >processor will see a keypress event for a, then >a keypress for b, then a keypress for c. >(although the order may be
: : : random).