-;    /* read input latch */
   IOCLK: BU(01FAFFFD)<-;    /* clock for serial I/O */
   STAT:  BU(01FAFFFF)<-;    /* port status */

PROBLEM;
   SPC A1    DATION INOUT ALPHIC CONTROL(ALL);
   SPC POUT  DATION   OUT BASIC;
   SPC RESET DATION IN    BASIC;
   SPC LIN   DATION IN    BASIC;
   SPC LOUT  DATION IN    BASIC;
   SPC PIN   DATION IN    BASIC;
   SPC PINL  DATION IN    BASIC;
   SPC IOCLK DATION IN    BASIC;
   SPC STAT  DATION IN    BASIC;

   DCL ECTRL BIT(16);                /* Eprommer control register */


/******************************************************************/
/*  procedure to read a single byte from an eprom                 */
/******************************************************************/
READBYTE: PROC (ADR BIT(16)) RETURNS (BIT(8));
   DCL DUMMY BIT(8);
   DCL BYTE BIT(16);

   ADR = ADR OR '8000'B4;            /* pin 1 to 5V */
   ECTRL = ECTRL AND 'FFEF'B4;       /* /OE low */
   SEND ECTRL TO POUT;
   TAKE DUMMY FROM IOCLK;
   SEND ADR TO POUT;                 /* set address */
   TAKE DUMMY FROM LOUT;             /* /CE low */
   TAKE BYTE  FROM PINL;             /* read byte, /CE high */
   ECTRL = ECTRL OR '0010'B4;        /* /OE high */
   SEND ECTRL TO POUT;
   TAKE DUMMY FROM IOCLK;
   RETURN(BYTE SHIFT 8);
END;   /* READBYTE:PROC */

/******************************************************************/
/*  task to call the READBYTE procedure for 16 subsequent bytes   */
/******************************************************************/
TEST:TASK;
   DCL DUMMY BIT(8);
   DCL BYTE BIT(8);
   DCL ADR BIT(16);

   ECTRL = '0001'B4;                 /* software reset */
   SEND ECTRL TO POUT;
   TAKE DUMMY FROM IOCLK;

   ECTRL = '8009'B4;                 /* pin 1,28 to 5V */
                                     /* data latch disabled */
   PUT 'Addr: ' TO A1 BY SKIP,A;
   GET ADR FROM A1 BY SKIP,B4(4);
   PUT ADR,':  ' TO A1 BY SKIP,B4(4),A;
   TO 16 REPEAT
      BYTE = READBYTE(ADR);
      PUT BYTE,' ' TO A1 BY B4(2),A;
      ADR = TOBIT(TOFIXED(ADR) + 1);
   END;
   ECTRL = '0001'B4;                 /* pin 1,28 to 0V */
   SEND ECTRL TO POUT;
   TAKE DUMMY FROM IOCLK;
END;   /* TEST: TASK; */

/******************************************************************/
/*  task to reset the userport                                    */
/******************************************************************/
RESET: TASK;
   DCL DUMMY BIT(8);

   ECTRL = '0001'B4;                 /* pin 1,28 to 0V */
   SEND ECTRL TO POUT;
   TAKE DUMMY FROM IOCLK;
END;   /* RESET: TASK; */


MODEND;