/* a simple DLL simulation in irsim */
#include <stdio.h>
#include "subckt.h"

uptr flop_func();
uptr flop_init();
uptr dll_init();
uptr dll();

#define	DEBUG	0

#define	printf	if (DEBUG) printf


userSubCircuit subs[] =
{
    { "flop",		flop_func,	flop_init	},
    { "dll",		dll,		dll_init	},
    { NULL,		NULL,		NULL		}
};

typedef struct _flopState {
	int prvClk ;
	int Q ;
} flopState;

uptr flop_init()
{
	flopState *thisFlop = (flopState *)malloc(sizeof(flopState));

	thisFlop->prvClk = HIGH ;
	thisFlop->Q = X ;
	return (uptr) thisFlop;
}


uptr flop_func( ins, outs, delay, data )
char *ins, *outs;
double *delay;
uptr  *data;
{
	flopState *ff = (flopState *)data ;

	if ( ff->prvClk == LOW && ins[1] == HIGH ) {
		printf("flop edge @ %.2fns\n", d2ns( cur_delta ));
		ff->Q = ins[0];
	}
	delay[0] = 100.0 ;
	ff->prvClk = ins[1];
	outs[0] = ff->Q;
}

typedef struct _dll_state {
	double chpmpV; /* the charge pump voltage */
	int    prvClk;
} dll_state ;

#define RAIL 	3.3 /* rail of the charge pump 0 - 3.3 */
#define UDPULSE	2e-9 /* 2ns pulse */
#define CHPMP_I	100e-6 /* 100 uA chpmp current */
#define PMP_CAP	20e-12 /* 10 pf filter cap */
#define CHGPCKT	(CHPMP_I*UDPULSE/PMP_CAP) /* charge packet */

uptr dll_init()
{
	dll_state *t = (dll_state *)malloc(sizeof(dll_state));

	t->chpmpV = 0.0 ;
	t->prvClk = LOW ;
	return (uptr) t;
}


#define	DLY0		2800.0	/* 1.8ns start delay */
#define	DLYSLOPE	1000.0	/* 1.0ns/V dline gain */
#define	DLINE_TF(V) (DLY0+DLYSLOPE*(V))

uptr dll( in, out, delay, data )
char *in, *out;
double *delay;
uptr  *data;
#define	clkOut	(out[0])
{
	dll_state *d = (dll_state *)data ;
	char    updn = in[0], clkIn = in[1], clkOutFb = in[2];


	printf("dll called @ %.2fns voltage %lf \n", d2ns( cur_delta ), 
	 d->chpmpV);
	printf("\t updn=%c clkin=%c clkOutFb=%c prevClk=%c\n", 
	pot2char[updn], pot2char[clkIn], pot2char[clkOutFb],
	pot2char[d->prvClk]);
	delay[0] = DLINE_TF(d->chpmpV);
	clkOut   = clkIn;

	if ( d->prvClk == LOW && clkOutFb == HIGH ) {
		d->chpmpV += (updn == HIGH) ? CHGPCKT : -CHGPCKT ;
		printf("pumping %s @ %.2fns voltage %le\n", 
			(updn == LOW) ? "up" : "dn",
			d2ns( cur_delta ), d->chpmpV);
	}
	d->prvClk = clkOutFb ;
}