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);
}
void nsc810_device::write(offs_t offset, uint8_t data)
{
uint32_t rate;
if(m_ramselect)
{
// TODO: 128 byte RAM access
}
else
{
// Register access
switch(offset & 0x1f)
{
case REG_PORTA:
m_portA_latch = data & ~m_ddrA;
m_portA_w((0xff & ~m_ddrA) | (data & m_ddrA));
LOG("NSC810: Port A data write %02x\n",data);
break;
case REG_PORTB:
m_portB_latch = data & ~m_ddrB;
m_portB_w((0xff & ~m_ddrB) | (data & m_ddrB));
LOG("NSC810: Port B data write %02x\n",data);
break;
case REG_PORTC:
m_portC_latch = data & ~m_ddrC;
m_portC_w((0xff & ~m_ddrC) | (data & m_ddrC));
LOG("NSC810: Port C data write %02x\n",data);
break;
case REG_DDRA:
m_ddrA = data;
LOG("NSC810: Port A direction write %02x\n",data);
break;
case REG_DDRB:
m_ddrB = data;
LOG("NSC810: Port B direction write %02x\n",data);
break;
case REG_DDRC:
m_ddrC = data;
LOG("NSC810: Port C direction write %02x\n",data);
break;
case REG_MODE_DEF:
LOG("NSC810: Mode Definition write %02x\n",data);
break;
case REG_PORTA_BITCLR:
LOG("NSC810: Port A bit-clear write %02x\n",data);
break;
case REG_PORTB_BITCLR:
LOG("NSC810: Port B bit-clear write %02x\n",data);
break;
case REG_PORTC_BITCLR:
LOG("NSC810: Port C bit-clear write %02x\n",data);
break;
case REG_PORTA_BITSET:
LOG("NSC810: Port A bit-set write %02x\n",data);
break;
case REG_PORTB_BITSET:
LOG("NSC810: Port B bit-set write %02x\n",data);
break;
case REG_PORTC_BITSET:
LOG("NSC810: Port C bit-set write %02x\n",data);
break;
case REG_TIMER0_LOW:
m_timer0_base = (m_timer0_base & 0xff00) | data;
m_timer0_counter = (m_timer0_counter & 0xff00) | data;
LOG("NSC810: Timer 0 low-byte write %02x (base=%04x)\n",data,m_timer0_base);
break;
case REG_TIMER0_HIGH:
m_timer0_base = (m_timer0_base & 0x00ff) | (data << 8);
m_timer0_counter = (m_timer0_counter & 0x00ff) | (data << 8);
LOG("NSC810: Timer 0 high-byte write %02x (base=%04x)\n",data,m_timer0_base);
break;
case REG_TIMER1_LOW:
m_timer1_base = (m_timer1_base & 0xff00) | data;
m_timer1_counter = (m_timer1_counter & 0xff00) | data;
LOG("NSC810: Timer 1 low-byte write %02x (base=%04x)\n",data,m_timer1_base);
break;
case REG_TIMER1_HIGH:
m_timer1_base = (m_timer1_base & 0x00ff) | (data << 8);
m_timer1_counter = (m_timer1_counter & 0x00ff) | (data << 8);
LOG("NSC810: Timer 1 high-byte write %02x (base=%04x)\n",data,m_timer1_base);
break;
case REG_TIMER0_STOP:
m_timer0_running = false;
m_timer0->reset();
LOG("NSC810: Timer 0 Stop write %02x\n",tag(),data);
break;
case REG_TIMER0_START:
if((m_timer0_mode & 0x07) != 0x00 && (m_timer0_mode & 0x07) != 0x07)
{
m_timer0_running = true;
if(m_timer0_mode & 0x10)
rate = m_timer0_clock / 64;
else
if(m_timer0_mode & 0x08)
rate = m_timer0_clock / 2;
else
rate = m_timer0_clock;
m_timer0->adjust(attotime::zero,0,attotime::from_hz(rate));
}
LOG("NSC810: Timer 0 Start write %02x\n",data);
break;
case REG_TIMER1_STOP:
m_timer1_running = false;
m_timer1->reset();
LOG("NSC810: Timer 1 Stop write %02x\n",data);
break;
case REG_TIMER1_START:
if((m_timer1_mode & 0x07) != 0x00 && (m_timer1_mode & 0x07) != 0x07)
{
m_timer1_running = true;
// no /64 prescaler on timer 1
if(m_timer0_mode & 0x08)
rate = m_timer0_clock / 2;
else
rate = m_timer0_clock;
m_timer1->adjust(attotime::zero,0,attotime::from_hz(rate));
}
LOG("NSC810: Timer 1 Start write %02x\n",data);
break;
case REG_MODE_TIMER0:
m_timer0_mode = data;
LOG("NSC810: Timer 0 Mode write %02x\n",data);
break;
case REG_MODE_TIMER1:
m_timer1_mode = data;
LOG("NSC810: Timer 1 Mode write %02x\n",data);
break;
default:
logerror("NSC810: Unused register %02x write %02x\n",offset,data);
}
}
}