dr@ski.UUCP (David Robins) (12/25/87)
In article <> tgm@xroads.UUCP (Sloan Tash) writes: >In article <1564@ttidca.TTI.COM>, paulb@ttidca.TTI.COM (Paul Blumstein) writes: >> Easily done! The open-apple and closed-apple correspond to joystick >> buttons 1 & 2. > >Actually, they're buttons 0 and 1. (You can read them with the PDL(0) or >PDL(1) commands). > >TGM >-- >\ / C r o s s r o a d s C o m m u n i c a t i o n s > \/ (602) 971-2240 > /\ (602) 992-5007 300|1200 Baud 24 hrs/day >/ \ ihnp4!mot!nud!xroads!* WRONG. The Applesoft PDL(n) function reads the paddle inputs, which are analog inputs. This gives a reading of 0-255, depending on the resistance (150K pot is standard) used in the potentiometer voltage divider on the input. To read the switch inputs (buttons 0,1,2 on joysticks, or Open-Apple, Closed Apple, and nothing on the keyboard) you need to use PEEKs from Applesoft. The addresses to peek are: Switch input 0 (open apl) : 49249 Switch input 1 (close apl) : 49250 Switch input 2 : 49251 The are read as PEEK(49249), for example. The switch input affects only bit 7 of the address. To see if sw. 0 is closed do this: A= PEEK (49249) PRINT A If A is less than 128, then the switch is open. If A is 128 or greater, it is closed. (Note than the reading at this address may vary; only its relationship to the number 128 is of any consequence.) You can also use the syntax: IF PEEK (49249) < 128 THEN ... or IF PEEK (49249) >= 128 THEN ... -- -dave ==================================================================== David Robins, M.D. (ophthalmologist / electronics engineer) Smith-Kettlewell Eye Research Foundation (previously known as: Smith-Kettlewell Institute of Visual Sciences) 2232 Webster St; San Francisco CA 94115 415/561-1705 (voice) {ihnp4,qantel,dual}!ptsfa!ski!dr The opinions expressed herein do not reflect the opinion of the Institute!