//============================================================
# ls243 source
//74LS243: Quad Transceiver (3-state)
//dm 9-10-97: Added IO_PAIRS.
//  Added io parameter to input LOAD.
//  Reduced ttlh_val/tthl_val to just tt_val.
//  Reduced tplh_val/tphl_val to just tp_val.
//  Removed v1 and r1 parameters from Vcc LOAD.
//  Added riccl, ricch and riccz and 5.25V for ricc max. calculations.
//  Added 3-state prop delays and corrected existing prop delay values
//  Reduced functional EXT_TABLE and fixed 3-state outputs
// Datasheet date: March 1987, revised Oct 1993.
// jjt 25/5/2000: * latch state in output table modified
//                * ricc_val calculation added to latch state logic
//                * ricc_val calculations added for other states 
//                * warning message code removed.
//============================================================
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, tp_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(4.75,5.25);	//check for min supply=4.75 and max supply=5.25
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(0.85,1.65);	//set input threshold values: vil and vih with hysteresis
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, 5n,  NULL));

    //NOTE: both tplh and tphl are the same value
    tp_val= (MIN_TYP_MAX(tp_param: NULL, 12n, 18n));

	tpzh_val= (MIN_TYP_MAX(tp_param: NULL, 15n, 23n));
    tpzl_val= (MIN_TYP_MAX(tp_param: NULL, 20n, 30n));

	tphz_val= (MIN_TYP_MAX(tp_param: NULL, 10n, 18n));
    tplz_val= (MIN_TYP_MAX(tp_param: NULL, 15n, 25n));

	//LS std output drive IOL max=24mA @ vol=0.4V: rol_param=(0.4-vol_param)/24mA
    rol_param= (MIN_TYP_MAX(drv_param: NULL, 8.34,  NULL));

	//tri-state drive IOZ max=20uA @ vo=2.4V: r3s_param=(2.4/20uA)
	r3s_param= (MIN_TYP_MAX(drv_param: 120k, NULL, NULL));

	//LS 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));

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

    //LS input load IIL=-0.2mA @ 0.4V: r1= (voh_param-0.4)/0.2mA
	rih_val= (MIN_TYP_MAX(ld_param: NULL, NULL, 21k));

	//Icch @ 5V with outputs high: 227.3= 5/22mA typical, 138.2= 5.25/38mA max
	ricch_val= (MIN_TYP_MAX(i_param: NULL, 227.3, 138.2));

	//Iccl @ 5V with outputs low: 172.4= 5/29mA typical, 105= 5.25/50mA max
	riccl_val= (MIN_TYP_MAX(i_param: NULL, 172.4, 105));

	//Iccz @ 5V with outputs 3-state: 156.3= 5/32mA typical, 97.2= 5.25/54mA max
	riccz_val= (MIN_TYP_MAX(i_param: NULL, 156.3, 97.2));

	//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 = (tp_val);
	    DELAY B3 B2 B1 B0 =
	      CASE (TRAN_ZH) : tpzh_val
	      CASE (TRAN_ZL) : tpzl_val
              CASE (1) : tp_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 outputs
            DELAY A3 A2 A1 A0 B3 B2 B1 B0 = 
	      CASE (TRAN_ZH) : tpzh_val
	      CASE (TRAN_ZL) : tpzl_val
              CASE (1) : tp_val
            END;
            outputs_high= (A3+A2+A1+A0+B3+B2+B1+B0);
            ricc_val= (((outputs_high*ricch_val)+((8-outputs_high)*riccl_val))/4);
          ELSE		//Bn(data) ->An(output)
		    DELAY B3 B2 B1 B0 = (tp_val);
            DELAY A3 A2 A1 A0 =
	          CASE (TRAN_ZH) : tpzh_val
	          CASE (TRAN_ZL) : tpzl_val
                  CASE (1) : tp_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;