void acia6850_device::device_reset()
{
int cts = devcb_call_read_line(&m_in_cts_func);
int dcd = devcb_call_read_line(&m_in_dcd_func);
m_status = (cts << 3) | (dcd << 2) | ACIA6850_STATUS_TDRE;
m_tdr = 0;
m_rdr = 0;
m_tx_shift = 0;
m_rx_shift = 0;
m_tx_counter = 0;
m_rx_counter = 0;
TXD(1);
m_overrun = 0;
m_status_read = 0;
m_brk = 0;
m_rx_state = START;
m_tx_state = START;
m_irq = 0;
devcb_call_write_line(&m_out_irq_func, 1);
if (m_first_reset)
{
m_first_reset = 0;
RTS(1);
}
else
{
RTS(m_rts);
}
}
READ8_DEVICE_HANDLER_TRAMPOLINE(acia6850, acia6850_data_r)
{
m_status &= ~(ACIA6850_STATUS_RDRF | ACIA6850_STATUS_IRQ | ACIA6850_STATUS_PE);
if (m_status_read)
{
int dcd = devcb_call_read_line(&m_in_dcd_func);
m_status_read = 0;
m_status &= ~(ACIA6850_STATUS_OVRN | ACIA6850_STATUS_DCD);
if (dcd)
{
m_status |= ACIA6850_STATUS_DCD;
}
}
if (m_overrun == 1)
{
m_status |= ACIA6850_STATUS_OVRN;
m_overrun = 0;
}
check_interrupts();
return m_rdr;
}
static UINT8 control_b_r(const device_config *device)
{
pia6821_state *p = get_token(device);
UINT8 ret;
/* update CB1 & CB2 if callback exists, these in turn may update IRQ's */
if (p->in_cb1_func.read != NULL)
pia6821_cb1_w(device, 0, devcb_call_read_line(&p->in_cb1_func));
else if (!p->logged_cb1_not_connected && !p->in_cb1_pushed)
{
logerror("PIA #%s: Error! no CB1 read handler. Three-state pin is undefined\n", device->tag);
p->logged_cb1_not_connected = TRUE;
}
if (p->in_cb2_func.read != NULL)
pia6821_cb2_w(device, 0, devcb_call_read_line(&p->in_cb2_func));
else if (!p->logged_cb2_not_connected && C2_INPUT(p->ctl_b) && !p->in_cb2_pushed)
{
logerror("PIA #%s: Error! No CB2 read handler. Three-state pin is undefined\n", device->tag);
p->logged_cb2_not_connected = TRUE;
}
/* read control register */
ret = p->ctl_b;
/* set the IRQ flags if we have pending IRQs */
if (p->irq_b1)
ret |= PIA_IRQ1;
if (p->irq_b2 && C2_INPUT(p->ctl_b))
ret |= PIA_IRQ2;
LOG(("PIA #%s: control B read = %02X\n", device->tag, ret));
return ret;
}
static UINT8 control_a_r(const device_config *device)
{
pia6821_state *p = get_token(device);
UINT8 ret;
/* update CA1 & CA2 if callback exists, these in turn may update IRQ's */
if (p->in_ca1_func.read != NULL)
pia6821_ca1_w(device, 0, devcb_call_read_line(&p->in_ca1_func));
else if (!p->logged_ca1_not_connected && (!p->in_ca1_pushed))
{
logerror("PIA #%s: Warning! No CA1 read handler. Assuming pin not connected\n", device->tag);
p->logged_ca1_not_connected = TRUE;
}
if (p->in_ca2_func.read != NULL)
pia6821_ca2_w(device, 0, devcb_call_read_line(&p->in_ca2_func));
else if ( !p->logged_ca2_not_connected && C2_INPUT(p->ctl_a) && !p->in_ca2_pushed)
{
logerror("PIA #%s: Warning! No CA2 read handler. Assuming pin not connected\n", device->tag);
p->logged_ca2_not_connected = TRUE;
}
/* read control register */
ret = p->ctl_a;
/* set the IRQ flags if we have pending IRQs */
if (p->irq_a1)
ret |= PIA_IRQ1;
if (p->irq_a2 && C2_INPUT(p->ctl_a))
ret |= PIA_IRQ2;
LOG(("PIA #%s: control A read = %02X\n", device->tag, ret));
return ret;
}
void acia6850_device::rx_clock_in()
{
int dcd = devcb_call_read_line(&m_in_dcd_func);
if (dcd)
{
m_status |= ACIA6850_STATUS_DCD;
check_interrupts();
}
else if ((m_status & (ACIA6850_STATUS_DCD|ACIA6850_STATUS_IRQ)) == ACIA6850_STATUS_DCD)
{
m_status &= ~ACIA6850_STATUS_DCD;
}
m_rx_counter ++;
if ( m_rx_counter > m_divide - 1)
{
rx_tick();
m_rx_counter = 0;
}
}
void acia6850_device::tx_clock_in()
{
int _cts = devcb_call_read_line(&m_in_cts_func);
if (_cts)
{
m_status |= ACIA6850_STATUS_CTS;
}
else
{
m_status &= ~ACIA6850_STATUS_CTS;
}
m_tx_counter ++;
if ( m_tx_counter > m_divide - 1)
{
tx_tick();
m_tx_counter = 0;
}
}
void acia6850_device::rx_tick()
{
int dcd = devcb_call_read_line(&m_in_dcd_func);
if (dcd)
{
m_status |= ACIA6850_STATUS_DCD;
check_interrupts();
}
else if ((m_status & (ACIA6850_STATUS_DCD | ACIA6850_STATUS_IRQ)) == ACIA6850_STATUS_DCD)
{
m_status &= ~ACIA6850_STATUS_DCD;
}
if (m_status & ACIA6850_STATUS_DCD)
{
m_rx_state = START;
}
else
{
int rxd = devcb_call_read_line(&m_in_rx_func);
switch (m_rx_state)
{
case START:
{
if (rxd == 0)
{
if (LOG) logerror("MC6850 '%s': RX START BIT\n", tag());
m_rx_shift = 0;
m_rx_parity = 0;
m_rx_bits = m_bits;
m_rx_state = DATA;
}
break;
}
case DATA:
{
if (LOG) logerror("MC6850 '%s': RX DATA BIT %x\n", tag(), rxd);
m_rx_shift |= rxd ? 0x80 : 0;
m_rx_parity ^= rxd;
if (--m_rx_bits == 0)
{
if (m_status & ACIA6850_STATUS_RDRF)
{
m_overrun = 1;
check_interrupts();
}
m_rx_state = m_parity == NONE ? STOP : PARITY;
}
else
{
m_rx_shift >>= 1;
}
break;
}
case PARITY:
{
if (LOG) logerror("MC6850 '%s': RX PARITY BIT %x\n", tag(), rxd);
m_rx_parity ^= rxd;
if (m_parity == EVEN)
{
if (m_rx_parity)
{
m_status |= ACIA6850_STATUS_PE;
}
}
else
{
if (!m_rx_parity)
{
m_status |= ACIA6850_STATUS_PE;
}
}
m_rx_state = STOP;
break;
}
case STOP:
{
if (rxd == 1)
{
if (LOG) logerror("MC6850 '%s': RX STOP BIT\n", tag());
if (m_stopbits == 1)
{
m_status &= ~ACIA6850_STATUS_FE;
if (!(m_status & ACIA6850_STATUS_RDRF))
{
if (LOG) logerror("MC6850 '%s': RX DATA %x\n", tag(), m_rx_shift);
m_rdr = m_rx_shift;
m_status |= ACIA6850_STATUS_RDRF;
check_interrupts();
}
m_rx_state = START;
}
else
{
m_rx_state = STOP2;
}
}
else
{
m_status |= ACIA6850_STATUS_FE;
m_rx_state = START;
}
break;
}
case STOP2:
{
if (rxd == 1)
{
if (LOG) logerror("MC6850 '%s': RX STOP BIT\n", tag());
m_status &= ~ACIA6850_STATUS_FE;
if (!(m_status & ACIA6850_STATUS_RDRF))
{
if (LOG) logerror("MC6850 '%s': RX DATA %x\n", tag(), m_rx_shift);
m_rdr = m_rx_shift;
m_status |= ACIA6850_STATUS_RDRF;
check_interrupts();
}
m_rx_state = START;
}
else
{
m_status |= ACIA6850_STATUS_FE;
m_rx_state = START;
}
break;
}
}
}
}
void acia6850_device::tx_tick()
{
switch (m_tx_state)
{
case START:
{
if (m_brk)
{
// transmit break
TXD(0);
}
else
{
int _cts = devcb_call_read_line(&m_in_cts_func);
if (_cts)
{
m_status |= ACIA6850_STATUS_CTS;
}
else
{
m_status &= ~ACIA6850_STATUS_CTS;
}
check_interrupts();
if (m_status & ACIA6850_STATUS_TDRE)
{
// transmitter idle
TXD(1);
}
else
{
// transmit character
if (LOG) logerror("MC6850 '%s': TX DATA %x\n", tag(), m_tdr);
if (LOG) logerror("MC6850 '%s': TX START BIT\n", tag());
TXD(0);
m_tx_bits = m_bits;
m_tx_shift = m_tdr;
m_tx_parity = 0;
m_tx_state = DATA;
}
}
break;
}
case DATA:
{
int val = m_tx_shift & 1;
if (LOG) logerror("MC6850 '%s': TX DATA BIT %x\n", tag(), val);
TXD(val);
m_tx_parity ^= val;
m_tx_shift >>= 1;
if (--(m_tx_bits) == 0)
{
m_tx_state = (m_parity == NONE) ? STOP : PARITY;
}
break;
}
case PARITY:
{
int parity = 0;
if (m_parity == EVEN)
{
parity = (m_tx_parity & 1) ? 1 : 0;
}
else
{
parity = (m_tx_parity & 1) ? 0 : 1;
}
TXD(parity);
if (LOG) logerror("MC6850 '%s': TX PARITY BIT %x\n", tag(), parity);
m_tx_state = STOP;
break;
}
case STOP:
{
if (LOG) logerror("MC6850 '%s': TX STOP BIT\n", tag());
TXD(1);
if (m_stopbits == 1)
{
m_tx_state = START;
m_status |= ACIA6850_STATUS_TDRE;
}
else
{
m_tx_state = STOP2;
}
break;
}
case STOP2:
{
if (LOG) logerror("MC6850 '%s': TX STOP BIT\n", tag());
TXD(1);
m_tx_state = START;
m_status |= ACIA6850_STATUS_TDRE;
break;
}
}
}