void coco_fdc_device_base::update_lines()
{
// clear HALT enable under certain circumstances
if (intrq() && (dskreg() & 0x20))
set_dskreg(dskreg() & ~0x80); // clear halt enable
// set the NMI line
set_line_value(line::NMI, intrq() && (dskreg() & 0x20));
// set the HALT line
set_line_value(line::HALT, !drq() && (dskreg() & 0x80));
}
void dragon_fdc_device_base::update_lines()
{
// set the NMI line
set_line_value(line::NMI, intrq() && (dskreg() & 0x20));
// set the CART line
set_line_value(line::CART, drq());
}
void coco_fdc_device_base::dskreg_w(uint8_t data)
{
uint8_t drive = 0;
uint8_t head;
if (LOG_FDC)
{
logerror("fdc_coco_dskreg_w(): %c%c%c%c%c%c%c%c ($%02x)\n",
data & 0x80 ? 'H' : 'h',
data & 0x40 ? '3' : '.',
data & 0x20 ? 'D' : 'S',
data & 0x10 ? 'P' : 'p',
data & 0x08 ? 'M' : 'm',
data & 0x04 ? '2' : '.',
data & 0x02 ? '1' : '.',
data & 0x01 ? '0' : '.',
data);
}
// An email from John Kowalski informed me that if the DS3 is
// high, and one of the other drive bits is selected (DS0-DS2), then the
// second side of DS0, DS1, or DS2 is selected. If multiple bits are
// selected in other situations, then both drives are selected, and any
// read signals get yucky.
if (data & 0x04)
drive = 2;
else if (data & 0x02)
drive = 1;
else if (data & 0x01)
drive = 0;
else if (data & 0x40)
drive = 3;
// the motor is always turned on or off for all drives
for (int i = 0; i < 4; i++)
{
floppy_image_device *floppy = m_floppies[i]->get_device();
if (floppy)
floppy->mon_w(BIT(data, 3) ? 0 : 1);
}
head = ((data & 0x40) && (drive != 3)) ? 1 : 0;
set_dskreg(data);
update_lines();
floppy_image_device *selected_floppy = m_floppies[drive]->get_device();
m_wd17xx->set_floppy(selected_floppy);
if (selected_floppy)
selected_floppy->ss_w(head);
m_wd17xx->dden_w(!BIT(dskreg(), 5));
}