void nsc810_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
{
switch(id)
{
case TIMER0_CLOCK:
m_timer0_counter--;
if((m_timer0_mode & 0x07) == 0x01 || (m_timer0_mode & 0x07) == 0x02)
{
if(m_timer0_counter == 0)
{
m_timer0_out(ASSERT_LINE);
m_timer0_counter = m_timer0_base;
if(LOG) logerror("NSC810 '%s': Timer 0 output set\n",tag());
}
}
break;
case TIMER1_CLOCK:
m_timer1_counter--;
if((m_timer1_mode & 0x07) == 0x01 || (m_timer1_mode & 0x07) == 0x02)
{
if(m_timer1_counter == 0)
{
m_timer1_out(ASSERT_LINE);
m_timer1_counter = m_timer1_base;
if(LOG) logerror("NSC810 '%s': Timer 1 output set\n",tag());
}
}
break;
}
}
void nsc810_device::device_start()
{
m_portA_r.resolve_safe(0);
m_portB_r.resolve_safe(0);
m_portC_r.resolve_safe(0);
m_portA_w.resolve_safe();
m_portB_w.resolve_safe();
m_portC_w.resolve_safe();
m_timer0_out.resolve_safe();
m_timer1_out.resolve_safe();
m_portA_w(0);
m_portB_w(0);
m_portC_w(0);
m_timer0_out(0);
m_timer1_out(0);
m_timer0 = timer_alloc(TIMER0_CLOCK);
m_timer1 = timer_alloc(TIMER1_CLOCK);
}
uint8_t nsc810_device::read(offs_t offset)
{
uint8_t res = 0xff;
if(m_ramselect)
{
// TODO: 128 byte RAM access
}
else
{
// Register access
switch(offset & 0x1f)
{
case REG_PORTA:
res = m_portA_latch &= m_ddrA;
res |= (m_portA_r() & ~m_ddrA);
//LOG("NSC810: Port A data read %02x\n",res);
break;
case REG_PORTB:
res = m_portB_latch &= m_ddrB;
res |= (m_portB_r() & ~m_ddrB);
//LOG("NSC810: Port B data read %02x\n",res);
break;
case REG_PORTC:
res = m_portC_latch &= m_ddrC;
res |= (m_portC_r() & ~m_ddrC);
//LOG("NSC810: Port C data read %02x\n",res);
break;
case REG_MODE_TIMER0:
res = m_timer0_mode;
break;
case REG_MODE_TIMER1:
res = m_timer1_mode;
break;
case REG_TIMER0_LOW:
res = m_timer0_counter & 0xff;
if((m_timer0_mode & 0x07) == 0x01 || (m_timer0_mode & 0x07) == 0x02)
{
m_timer0_out(CLEAR_LINE);
LOG("NSC810: Timer 0 output reset\n");
}
break;
case REG_TIMER0_HIGH:
res = m_timer0_counter >> 8;
if((m_timer0_mode & 0x07) == 0x01 || (m_timer0_mode & 0x07) == 0x02)
{
m_timer0_out(CLEAR_LINE);
LOG("NSC810: Timer 0 output reset\n");
}
break;
case REG_TIMER1_LOW:
res = m_timer1_counter & 0xff;
if((m_timer1_mode & 0x07) == 0x01 || (m_timer1_mode & 0x07) == 0x02)
{
m_timer1_out(0);
LOG("NSC810: Timer 1 output reset\n");
}
break;
case REG_TIMER1_HIGH:
res = m_timer1_counter >> 8;
if((m_timer1_mode & 0x07) == 0x01 || (m_timer1_mode & 0x07) == 0x02)
{
m_timer1_out(0);
LOG("NSC810: Timer 1 output reset\n");
}
break;
default:
LOG("NSC810: unused port %02x read\n",offset);
}
}
return res;
}
