PAL16R4                                         PAL DESIGN SPECIFICATION
P7015                                              DAVE SACKETT 02/23/81
STEPPER MOTOR CONTROLLER
DEVOE COMPANY, INDIANAPOLIS, INDIANA
CLK /E1A /E2A SA DA /E1B /E2B SB DB GND
/OC /Q3B /Q1B /Q2B /Q0B /Q2A /Q0A /Q3A /Q1A VCC


Q0A :=  Q0A*/E1A                ;HOLD IF NOT E1
     +  Q0A*/E2A                ;HOLD IF NOT E2
     +  SA * E1A* E2A           ;STEP 1 IF SET
     + /Q2A* E1A* E2A* DA       ;LOAD /Q2A IF COUNTER-CLOCKWISE
     +  Q2A* E1A* E2A*/DA       ;LOAD  Q2A IF CLOCKWISE

IF (VCC) Q1A = /Q0A

Q2A :=  Q2A*/E1A                ;HOLD IF NOT E1
     +  Q2A*/E2A                ;HOLD IF NOT E2
     +  SA * E1A* E2A           ;STEP 1 IF SET
     +  Q0A* E1A* E2A* DA       ;LOAD  Q0A IF COUNTER-CLOCKWISE
     + /Q0A* E1A* E2A*/DA       ;LOAD /Q0A IF CLOCKWISE

IF (VCC) Q3A = /Q2A

Q0B :=  Q0B*/E1B                ;HOLD IF NOT E1
     +  Q0B*/E2B                ;HOLD IF NOT E2
     +  SB * E1B* E2B           ;STEP 1 IF SET
     + /Q2B* E1B* E2B* DB       ;LOAD /Q2B IF COUNTER-CLOCKWISE
     +  Q2B* E1B* E2B*/DB       ;LOAD  Q2B IF CLOCKWISE

IF (VCC) Q1B = /Q0B

Q2B :=  Q2B*/E1B                ;HOLD IF NOT E1
     +  Q2B*/E2B                ;HOLD IF NOT E2
     +  SB * E1B* E2B           ;STEP 1 IF SET
     +  Q0B* E1B* E2B* DB       ;LOAD  Q0B IF COUNTER-CLOCKWISE
     + /Q0B* E1B* E2B*/DB       ;LOAD /Q0B IF CLOCKWISE

IF (VCC) Q3B = /Q2B


FUNCTION TABLE

CLK /OC /E1A /E2A SA DA Q0A Q1A Q2A Q3A /E1B /E2B SB DB Q0B Q1B Q2B Q3B

;CHIP     STEPPER MOTOR A    STEPPER MOTOR B
;C  /      CONTROL  STEP      CONTROL  STEP
;L  O      E E S D  QQQQ      E E S D  QQQQ
;K  C      1 2 A A  0123      1 2 A A  0123      COMMENTS
-----------------------------------------------------------------
 C  L      L L H X  HLHL      L L H X  HLHL      SET TO STEP 1
 C  L      H H X X  HLHL      H H X X  HLHL      HOLD
 C  L      L L L L  HLLH      L L L H  LHHL      STEP A CW, B CCW
 C  L      L L L L  LHLH      L L L H  LHLH      STEP A CW, B CCW
 C  L      L L L L  LHHL      L L L H  HLLH      STEP A CW, B CCW
 C  L      L L L L  HLHL      L L L H  HLHL      STEP A CW, B CCW
 C  L      L L L L  HLLH      L L L H  LHHL      STEP A CW, B CCW
 C  L      L L L L  LHLH      L L L H  LHLH      STEP A CW, B CCW
 C  L      L L L H  HLLH      L L L L  LHHL      STEP A CCW, B CW
 C  L      H L L H  HLLH      H L L L  LHHL      HOLD
 C  L      L H L H  HLLH      L H L L  LHHL      HOLD
 C  L      L H H H  HLLH      L H H L  LHHL      HOLD
-----------------------------------------------------------------


DESCRIPTION

THIS PAL16R4 PROVIDES THE LOGIC LEVELS REQUIRED TO DRIVE TWO STEPPER MOTORS
IN THE FULL STEP MODE.

THE FOLLOWING OPERATIONS MAY BE PERFORMED FOR EACH STEPPER MOTOR CONTROLLER
INDIVIDUALLY:

        CLK   /E1   /E2   S    D    OPERATION
        ----------------------------------------------------------
         X     H     X    X    X    HOLD MOTOR IN CURRENT POSITION
         X     X     H    X    X    HOLD MOTOR IN CURRENT POSITION
         C     L     L    H    X    SET OUTPUTS TO STEP 1 LEVELS
         C     L     L    L    L    STEP MOTOR CLOCKWISE
         C     L     L    L    H    STEP MOTOR COUNTER-CLOCKWISE
        ----------------------------------------------------------

$