Buzz #07 06 июня 1997

Pentagon     Доработки     Железо

Iron - Connection Kempston-way controller to the Pentagon 128.

                       *** IRON ***



          PENTAGON-128. CONNECTING KEMPSTON-NAVIGATION.

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   If you download a computer game programs, then perhaps
noticed that almost all the games can be controlled not only 
from the keyboard, but with a joystick. Moreover, as the right 
to choose offers several types of joysticks - KEMPSTON, 
SINCLAIR, CURSOR, etc.


   KEMPSTON-interface is a parallel input port
information from the joystick on the data bus kompyutera.Etot 
port has an address of 31, but is commonly used cruder decoding 
the address when the port is chosen zero-state address bus or 
A5 A6, because is not typically used several external devices.

In addition to addresses in the port selection part signals the 
microprocessor - IORQ, RD, which corresponds to a reading of I 
/ O port. From bytes read media interest under 5 bits D0 ... 
D4, which reflect the state of the joystick contact: 

         D0 - "RIGHT" D1 - "LEFT"

         D2 - "DOWN" D3 - "UP"

         D4 - "FIRE"

   At various conditions of the joystick with his numbers read:



     STATE NAVIGATION D0 D1 D2 D3 D4 NUM

 BASELINE 0 0 0 0 0 0
 RIGHT 1 0 0 0 0 1
 LEFT 0 1 0 0 0 2
 DOWN 0 0 1 0 0 4
 UP 0 0 0 1 0 8
 RIGHT, DOWN 1 0 1 0 0 5
 LEFT, DOWN 0 1 1 0 0 6
 RIGHT, UP 1 0 0 1 0 9
 LEFT, UP 0 1 0 1 0 10
 FIRE 0 0 0 0 January 1916
 RIGHT, FIRE 1 0 0 0 January 1917
 LEFT, FIRE 0 1 0 0 January 1918
 DOWN, FIRE 0 0 1 0 January 1920
 UP, FIRE 0 0 0 1 January 1924
 RIGHT, DOWN, FIRE 1 0 1 0 21 January
 LEFT, DOWN, FIRE 0 1 1 0 January 1922
 RIGHT, UP, FIRE 1 0 0 1 January 1925
 LEFT, DOWN, FIRE 0 1 0 1 January 1926



   Note that after power up or pressing the RESET all
580BB55A ports are configured in input mode of informatsii.Krome
Addressing the port "A" is chosen such that makes it possible 
to use it as a joystick interface, which can be connected

as shown in Figure 1. The joystick will be chosen at zero on
Tire A5, RD, IORQ, which corresponds to addressing 
KEMPSTON-INTERFACE. 


            4 / RIGHT K
580VV55A RA0 / E

             3 / LEFT M

         RA1 / P

             2 / S DOWN

         PA2 / T

             1 / UP O

         Pa3 / N

             40 / FIRE

         RA4 / A

             39 M

         RA5 R1-R5 About

             38 10 ohms Fig.1 TH

         PA6 C

             37 t

         RA7 +5 V and

                                                          K



   After the interface was collected, make sure it
performance. It's enough to run a simple program:


    10 LET A = IN 1931

    20 CLS: PRINT AT 10,10; A

    30 PAUSE 15: GO TO 10


   In the neutral position of the joystick handle and properly
collected by an interface circuit in the center of the screen 
should display "0". When the slopes of the arm will receive 
adequate numbers, as recorded in the table above.