The usage of paddles with atari 2600

[belial]

Hi all,

 

im thinking about adding paddle controler support into my homebrew game. But i dont really understand how to use them. I have read into stella manual the following:

 

Only the paddle triggers are read from the PIA. The paddles themselves are read at INP0 thru INPT3 of the TIA. The paddle triggers can be read at SWCHA according to the following table :

 

Data Bit Paddle #

D7 P0

D6 P1

D5/D4 (not used)

D3 P2

D2 P3

D1/D0 (not used)

 

My Questions:

- In this table, there are P0 - P3, so its possible to connect up to 4 paddles to the atari 2600?

- They joystick uses SWCHA for its directions, but the paddle uses SWCHA for its triggers, so its not possible to give the game support for joystick and paddle at the same time, the user has to f.e. select at the beginning of the game into a menu wether he wants to use paddle OR joystick?

- When the paddles themself are read from INP0 to INP3, does INP0 mean paddle of player 1 was turned to the left, INP1 means the paddle of player 1 was moved to the right and so on?

 

As u can see, im a bit confused of how to use the paddles and i can test it out by myself becoz i dont have paddles at home. So i would be happy if someone could say some words about paddles here.

 

Thanx

 

Christian

[supercat]

Only the paddle triggers are read from the PIA. The paddles themselves are read at INP0 thru INPT3 of the TIA. The paddle triggers can be read at SWCHA according to the following table :

902559[/snapback]

 

Those values are only to read the buttons. To read the paddles themselves you have to write a latch to discharge the four paddle caps (I forget which latch that is), then release the latch and time how long it takes the inputs to trip. There are four read addresses, one for each pot. Unfortunately, the time required for the pots to trip is sufficiently long that you can't simply wait for them; you have to watch for the inputs while you're in the process of drawing the screen. Rather a nuisance, actually.

[belial]

This doesnt sound good. And the major problem is i dont have a paddle at the moment. I think i will concentrate on other things and try again the paddle stuff when i have bought one to test my code.