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Internet Message Format  |  1992-12-16  |  2.4 KB
  1. Path: sparky!uunet!olivea!spool.mu.edu!agate!linus!alliant!mydual!olson
  2. From: olson@mydual.uucp (Kirtland H. Olson)
  3. Newsgroups: comp.sys.ibm.pc.hardware
  4. Subject: Re: Help, Joystick values and 1280x1024
  5. Message-ID: <1992Dec16.153527.7309@mydual.uucp>
  6. Date: 16 Dec 92 15:35:27 GMT
  7. References: <724450360.15021@minster.york.ac.uk>
  8. Reply-To: olson%mydual.uucp@alliant.com
  9. Organization: The Harvard Group, 01451-0667
  10. Lines: 58
  11.  
  12. In article <724450360.15021@minster.york.ac.uk> wgt-a@minster.york.ac.uk writes:
  13. >Help! Does anyone know what value variable-resistors
  14. >are required for the joysick port on an IBM PC?
  15.  
  16. 100K
  17.  
  18. >And, as an aside, can anyone give a good reason why
  19. >they used open ended resistors, necessitating (SP?)
  20. >particular value resistors, when a potentiometer
  21. >setup (as in the good ol' BBC) would have
  22. >been MUCH more sensible?
  23.  
  24. Because it's the timing resistor of a circuit whose pulse width can be
  25. counted.  
  26.  
  27. Here are the details of the joystick connection.
  28.  
  29. You can attach two joysticks to the controller.  Each joystick follows
  30. this wiring diagram:
  31.  
  32.                    +------------------ 1,9 +5VDC
  33.                    |                   
  34.                    +---/\/\/\-- 0-100K
  35.                    |     ^
  36.                    |     |    X-coord
  37.                    |     +------------ 3,11 Timer
  38.                    |                   
  39.                    +---/\/\/\-- 0-100K
  40.                            ^
  41.                            |  Y-coord
  42.                            +---------- 6,13 Timer
  43.  
  44.                    +------------------ 2,10 One-Shots
  45.                  | o  #1 Button
  46.                  | o
  47.                    +------------------ 4,12 GND
  48.  
  49.                    +------------------ 7,14 One-Shots
  50.                  | o  #2 Button
  51.                  | o
  52.                    +------------------ 4,12 GND
  53.  
  54. Pins 1-7 Are for Joystick A, pins 9-14 are for joystick B.  You can also
  55. use paddles, having only one 0-100K pot and one button per controller. 
  56. The data show up in the same place but are named differently.  Here's a
  57. chart of the the byte at 201H:
  58.  
  59. Bit     |  7  |  6  |  5  |  4  |  3  |  2  |  1  |  0  |
  60. Joystick|B-#2 |B-#1 |A-#2 |A-#1 | B-Y | B-X | A-Y | A-X |
  61. Paddle  |  D  |  C  |  B  |  A  |  D  |  C  |  B  |  A  |
  62. Pin     | 14  | 10  |  7  |  2  | 13  | 11  |  6  |  3  |
  63. Device  |<-------Buttons------->|<------Resistors------>|
  64.  
  65.  
  66.  
  67.  
  68. -- 
  69. Kirtland H. Olson                     olson%mydual.uucp@alliant.com
  70.