//============================================================
# f242 source
// datasheet date: T.I. March 1987, revised Oct 1993.
//74F242: Quad Inverting Transceiver (3-state)
//dm 10-23-97: copied ls242 in LS.TXT
//      changed SUPPLY_MIN_MAX, VIL_VIL_VALUE,
//  iol, ioh, iil, iih, icc, rise, fall
//  and prop delays values.
// jjt 25/5/2000: * changed the output table to match the datasheet
//                * removed warning message code (including 
//                     the variables temp_msg and show_msg).
//                * added a ricc_val calculation to cater for the
//                     latch state and ricc_val calculations for the
//                     other states.
//============================================================
INPUTS VCC, GND, OEA, A3in, A2in, A1in, A0in,
       OEB, B3in, B2in, B1in, B0in;
OUTPUTS VCC_LD, OEA_LD, A3, A2, A1, A0, OEB_LD, B3, B2, B1, B0;
INTEGERS tblIndex, outputs_high ;
REALS tt_val, tplh_val, tphl_val, tpzl_val, tpzh_val, tplz_val, tphz_val,
      ril_val, rih_val, ricc_val, ricch_val, riccl_val, riccz_val;

PWR_GND_PINS(VCC,GND);          //set pwr_param and gnd_param values
SUPPLY_MIN_MAX(4.5,5.5);        //check for min supply=4.5 and max supply=5.5
VOL_VOH_MIN(0.2,-0.4,0.1);      //set min vol_param=gnd_param+0.2, max voh_param=pwr_param-0.4
VIL_VIH_VALUE(1.45,1.55);       //set input threshold values: vil and vih
IO_PAIRS(OEA:OEA_LD, OEB:OEB_LD);

IF (init_sim) THEN
  BEGIN
//MESSAGE("time\tOEA\tOEB\tA3\tA2\tA1\tA0\tB3\tB2\tB1\tB0");

    //NOTE: both ttlh and tthl are the same value
    tt_val= (MIN_TYP_MAX(tt_param: NULL, 2.5n,  NULL));

    tplh_val= (MIN_TYP_MAX(tp_param: 3n, 4.5n, 6.5n));
    tphl_val= (MIN_TYP_MAX(tp_param: 2n, 3n, 4.5n));

        tpzh_val= (MIN_TYP_MAX(tp_param: 3.5n, 6n, 7.5n));
    tpzl_val= (MIN_TYP_MAX(tp_param: 3.5n, 6.5n, 9n));

        tphz_val= (MIN_TYP_MAX(tp_param: 4n, 7n, 9n));
    tplz_val= (MIN_TYP_MAX(tp_param: 3.5n, 6n, 9.5n));

    //F std output drive IOL max=64mA @ vol=0.5V: rol_param=(0.5-vol_param)/64mA
    rol_param= (MIN_TYP_MAX(drv_param: NULL, 4.69,  NULL));

    //F std output drive IOH max=-15mA @ voh=4.5V: roh_param=(voh_param-4.5)/15mA
    roh_param= (MIN_TYP_MAX(drv_param: NULL, 6.67, NULL));

    //F input load IIH=20uA @ 2.7V: ril= (2.7-vol_param)/20uA;
    ril_val= (MIN_TYP_MAX(ld_param: NULL, NULL, 125k));

        //tri-state drive IOZ max=50uA @ vo=2.4V: r3s_param=(2.7/50uA)
        r3s_param= (MIN_TYP_MAX(drv_param: 54k, NULL, NULL));

    //F input load IIL=-1mA @ 0.5V: rih= (voh_param-0.5)/1mA
    rih_val= (MIN_TYP_MAX(ld_param: NULL, NULL, 4.1k));

    //Icch with output high: 227.3= 5V/22mA typical, 157.1= 5.5V/35mA max 
    ricch_val= (MIN_TYP_MAX(i_param: NULL, 227.3, 157.1));

    //Iccl with output low: 125= 5V/40mA typical, 100= 5.5V/55mA max 
    riccl_val= (MIN_TYP_MAX(i_param: NULL, 125, 100));

    //Iccz with output 3-state: 156.3= 5V/32mA typical, 122.2= 5.5V/45mA max 
    riccz_val= (MIN_TYP_MAX(i_param: NULL, 156.3, 122.2));

        //initialize output
        STATE A3 A2 A1 A0 B3 B2 B1 B0 = UNKNOWN;
        EXIT;
  END;

DRIVE A3 A2 A1 A0 B3 B2 B1 B0 =
  (v0=vol_param,v1=voh_param,ttlh=tt_val,tthl=tt_val);
LOAD OEA_LD OEB_LD =
  (v0=vol_param,r0=ril_val,v1=voh_param,r1=rih_val,io=1e9,t=1p);

EXT_TABLE tblIndex
OEA OEB A3    A2    A1    A0    B3    B2    B1    B0
0   0   Z     Z     Z     Z     ~A3in ~A2in ~A1in ~A0in
1   0   Z     Z     Z     Z     Z     Z     Z     Z
0   1   A3in  A2in  A1in  A0in  B3in  B2in  B1in  B0in
1   1   ~B3in ~B2in ~B1in ~B0in Z     Z     Z     Z;



IF (tblIndex = 2) THEN
  BEGIN                         //3-state all pins
    DELAY A3 A2 A1 A0 B3 B2 B1 B0 =
          CASE (TRAN_HZ) : tphz_val
          CASE (TRAN_LZ) : tplz_val
    END;
    ricc_val= (riccz_val);
  ELSE
    IF (tblIndex = 1) THEN
      BEGIN                     //An(data) -> Bn(output)
        DELAY A3 A2 A1 A0 = (tplh_val);
            DELAY B3 B2 B1 B0 =
          CASE (TRAN_LH) : tplh_val
          CASE (TRAN_HL) : tphl_val
              CASE (TRAN_ZH) : tpzh_val
              CASE (TRAN_ZL) : tpzl_val
        END;
        outputs_high= (B3+B2+B1+B0);
        ricc_val= (((outputs_high*ricch_val)+((4-outputs_high)*riccl_val))/4);
      ELSE
        IF (tblIndex = 3) THEN
          BEGIN         //  latch the outputs  
            DELAY A3 A2 A1 A0 B3 B2 B1 B0 = 
                  CASE (TRAN_HL) : tphl_val
                  CASE (TRAN_LH) : tplh_val             
                  CASE (TRAN_ZH) : tpzh_val
                  CASE (TRAN_ZL) : tpzl_val
            END;        
            outputs_high= (B3+B2+B1+B0+A3+A2+A1+A0);
            ricc_val= (((outputs_high*ricch_val)+((8-outputs_high)*riccl_val))/4);
          ELSE          //Bn(data) ->An(output)
                    DELAY B3 B2 B1 B0 = (tplh_val);
            DELAY A3 A2 A1 A0 =
              CASE (TRAN_LH) : tplh_val
              CASE (TRAN_HL) : tphl_val
              CASE (TRAN_ZH) : tpzh_val
              CASE (TRAN_ZL) : tpzl_val
            END;
            outputs_high= (A3+A2+A1+A0);
            ricc_val= (((outputs_high*ricch_val)+((4-outputs_high)*riccl_val))/4);
          END;
      END;
  END;

//MESSAGE("%fs\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d",
//         present_time,OEA,OEB,A3,A2,A1,A0,B3,B2,B1,B0);

LOAD VCC_LD = (v0=gnd_param,r0=ricc_val,t=1p);
EXIT;