UINT8 pia6821_device::port_a_r()
{
UINT8 ret = get_in_a_value();
// IRQ flags implicitly cleared by a read
m_irq_a1 = FALSE;
m_irq_a2 = FALSE;
update_interrupts();
// CA2 is configured as output and in read strobe mode
if(C2_OUTPUT(m_ctl_a) && C2_STROBE_MODE(m_ctl_a))
{
// this will cause a transition low
set_out_ca2(FALSE);
// if the CA2 strobe is cleared by the E, reset it right away
if(STROBE_E_RESET(m_ctl_a))
{
set_out_ca2(TRUE);
}
}
LOG(("PIA #%s: port A read = %02X\n", tag(), ret));
return ret;
}
static UINT8 port_a_r(const device_config *device)
{
pia6821_state *p = get_token(device);
UINT8 ret = get_in_a_value(device);
/* IRQ flags implicitly cleared by a read */
p->irq_a1 = FALSE;
p->irq_a2 = FALSE;
update_interrupts(device);
/* CA2 is configured as output and in read strobe mode */
if (C2_OUTPUT(p->ctl_a) && C2_STROBE_MODE(p->ctl_a))
{
/* this will cause a transition low */
set_out_ca2(device, FALSE);
/* if the CA2 strobe is cleared by the E, reset it right away */
if (STROBE_E_RESET(p->ctl_a))
set_out_ca2(device, TRUE);
}
LOG(("PIA #%s: port A read = %02X\n", device->tag, ret));
return ret;
}
void pia6821_device::control_a_w(UINT8 data)
{
// bit 7 and 6 are read only
data &= 0x3f;
LOG(("PIA #%s: control A write = %02X\n", tag(), data));
// update the control register
m_ctl_a = data;
// CA2 is configured as output
if(C2_OUTPUT(m_ctl_a))
{
int temp;
if(C2_SET_MODE(m_ctl_a))
{
// set/reset mode - bit value determines the new output
temp = C2_SET(m_ctl_a);
}
else
{
// strobe mode - output is always high unless strobed
temp = TRUE;
}
set_out_ca2(temp);
}
// update externals
update_interrupts();
}
static void control_a_w(const device_config *device, UINT8 data)
{
pia6821_state *p = get_token(device);
/* bit 7 and 6 are read only */
data &= 0x3f;
LOG(("PIA #%s: control A write = %02X\n", device->tag, data));
/* update the control register */
p->ctl_a = data;
/* CA2 is configured as output */
if (C2_OUTPUT(p->ctl_a))
{
int temp;
if (C2_SET_MODE(p->ctl_a))
/* set/reset mode - bit value determines the new output */
temp = C2_SET(p->ctl_a);
else
/* strobe mode - output is always high unless strobed */
temp = TRUE;
set_out_ca2(device, temp);
}
/* update externals */
update_interrupts(device);
}
