#define WR 2
#define P_BUSREQ PORTD
#define BUSREQ 7
+#define PIN_BUSREQ PIND
#define DDR_BUSREQ DDRD
#define P_BUSACK PORTD
#define PIN_BUSACK PIND
#define Z80_O_RD SBIT(P_RD, 3)
#define Z80_O_WR SBIT(P_WR, 2)
#define Z80_O_BUSREQ SBIT(P_BUSREQ, 7)
+#define Z80_I_BUSREQ SBIT(PIN_BUSREQ, 7)
//#define Z80_O_NMI SBIT(P_NMI, )
#define Z80_O_RST SBIT(P_RST, 5)
#define Z80_I_RST SBIT(PIN_RST, 5)
static zstate_t zstate;
static volatile uint8_t timer; /* used for bus timeout */
+
+static volatile uint16_t busack_cycles_ovl;
+
+static uint32_t busack_cycles;
+
+ISR(TIMER4_COMPB_vect)
+{
+ busack_cycles_ovl++;
+}
+
/*---------------------------------------------------------*/
/* 10Hz timer interrupt generated by OC5A */
/*---------------------------------------------------------*/
}
+uint32_t z80_get_busreq_cycles(void)
+{
+ return busack_cycles;
+}
+
zstate_t z80_bus_state(void)
{
return zstate;
}
+void z80_toggle_reset(void)
+{
+ Z80_I_RST = 1;
+}
+
+void z80_toggle_busreq(void)
+{
+ Z80_I_BUSREQ = 1;
+}
+
static void z80_busreq_hpulse(void)
{
z80_dbus_set_in();
z80_addrbus_set_in();
z80_reset_active();
+ _delay_us(10);
Z80_O_BUSREQ = 1;
timer = BUS_TO;
while (Z80_I_BUSACK == 0 && timer)
switch (zstate) {
case RESET:
Z80_O_BUSREQ = 0;
- z80_reset_inactive();
- timer = BUS_TO;
+ timer = 255; //BUS_TO;
+
+ uint16_t tcnt;
+ uint16_t ovl_cnt;
+ uint8_t ifr;
+ busack_cycles = 0;
+ busack_cycles_ovl = 0;
+ ATOMIC_BLOCK(ATOMIC_FORCEON) {
+ //z80_reset_inactive();
+ Z80_I_RST = 1; /* Toggle RESET --> inactive */
+ OCR4B = TCNT4;
+ TIFR4 = _BV(OCF4B); /* Clear compare match flag */
+ }
+ TIMSK4 |= _BV(OCIE4B); /* Enable compare match interrupt */
+
while (Z80_I_BUSACK == 1 && timer)
;
+
+ ATOMIC_BLOCK(ATOMIC_FORCEON) {
+ tcnt = TCNT4 - OCR4B;
+ ovl_cnt = busack_cycles_ovl;
+ ifr = TIFR4;
+ TIMSK4 &= ~_BV(OCIE4B); /* Disable compare match interrupt */
+ }
if (Z80_I_BUSACK == 0) {
+ if ((ifr & _BV(OCF4B)) && !(tcnt & (1<<15)))
+ ovl_cnt++;
+ busack_cycles = tcnt + ((uint32_t) ovl_cnt << 16);
z80_addrbus_set_out();
zstate = RESET_AQRD;
+// debug("### ovl: %u, ifr: %u, beg: %u, end: %u\n", ovl_cnt,
+// (ifr & _BV(OCF4B)) != 0, OCR4B, tcnt);
} else {
z80_reset_active();
Z80_O_BUSREQ = 1;
z80_dbus_set_in();
z80_addrbus_set_in();
z80_reset_active();
+ _delay_us(10);
Z80_O_BUSREQ = 1;
timer = BUS_TO;
while (Z80_I_BUSACK == 0 && timer)