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mt420: Add VRAM and preliminary character drawing

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This commit is contained in:
AJR 2021-07-03 08:01:09 -04:00
parent 4727870a8c
commit b8fb155b08
1 changed files with 64 additions and 15 deletions
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79
src/mame/drivers/mt420.cpp
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@ -23,41 +23,80 @@ public:
mt420_state(const machine_config &mconfig, device_type type, const char *tag)
: driver_device(mconfig, type, tag)
, m_maincpu(*this, "maincpu")
, m_mainnmi(*this, "mainnmi")
, m_screen(*this, "screen")
, m_chargen(*this, "chargen")
, m_attrram(*this, "attrram")
, m_cgram(*this, "cgram")
, m_vram_view(*this, "vram")
, m_avdc_intr(false)
{
}
void mt420(machine_config &config);
private:
u8 c000_r();
SCN2674_DRAW_CHARACTER_MEMBER(draw_character);
DECLARE_WRITE_LINE_MEMBER(avdc_intr_w);
void control_w(u8 data);
u8 attr_r(offs_t offset);
void mem_map(address_map &map);
void io_map(address_map &map);
void vram_map(address_map &map);
void chars_map(address_map &map);
void attrs_map(address_map &map);
required_device<cpu_device> m_maincpu;
required_device<input_merger_device> m_mainnmi;
required_device<screen_device> m_screen;
required_region_ptr<u8> m_chargen;
required_shared_ptr<u8> m_attrram;
required_shared_ptr<u8> m_cgram;
memory_view m_vram_view;
bool m_avdc_intr;
};
WRITE_LINE_MEMBER(mt420_state::avdc_intr_w)
{
m_avdc_intr = state;
}
SCN2674_DRAW_CHARACTER_MEMBER(mt420_state::draw_character)
{
u16 dots = BIT(charcode, 7) ? m_cgram[u8(charcode & 0x7f) << 4 | linecount] : m_chargen[linecount << 7 | charcode];
dots |= dots << 1;
for (int i = 0; i < 12; i++)
{
bitmap.pix(y, x++) = BIT(dots, 8) ? rgb_t::white() : rgb_t::black();
if (i < 8)
dots <<= 1;
}
}
u8 mt420_state::c000_r()
void mt420_state::control_w(u8 data)
{
return machine().rand() & 0x80;
m_vram_view.select(BIT(data, 1));
m_mainnmi->in_w<1>(!BIT(data, 4));
}
u8 mt420_state::attr_r(offs_t offset)
{
// TBD: Bit 7 is special, but what is its source?
return (m_attrram[offset] & 0x7f) | (m_screen->vblank() || m_screen->hblank() || m_avdc_intr ? 0x80 : 0);
}
void mt420_state::mem_map(address_map &map)
{
map(0x0000, 0x7fff).rom().region("maincpu", 0);
map(0x9000, 0x9000).nopw();
map(0xc000, 0xc000).r(FUNC(mt420_state::c000_r)).nopw();
map(0xe000, 0xefff).ram();
map(0xeff8, 0xefff).rw("avdc", FUNC(scn2674_device::read), FUNC(scn2674_device::write));
map(0x8000, 0x87ff).ram().share("cgram");
map(0x9000, 0x9000).w(FUNC(mt420_state::control_w));
map(0xc000, 0xcfff).writeonly().share("attrram").r(FUNC(mt420_state::attr_r));
map(0xe000, 0xefff).view(m_vram_view);
m_vram_view[0](0xeff8, 0xefff).rw("avdc", FUNC(scn2674_device::read), FUNC(scn2674_device::write));
m_vram_view[1](0xe000, 0xefff).ram().share("charram");
map(0xf000, 0xf7ff).ram();
}
@ -68,9 +107,15 @@ void mt420_state::io_map(address_map &map)
map(0xf0, 0xf3).rw("aci", FUNC(scn2641_device::read), FUNC(scn2641_device::write));
}
void mt420_state::vram_map(address_map &map)
void mt420_state::chars_map(address_map &map)
{
map(0x0000, 0x3fff).noprw();
map(0x0000, 0x0fff).ram().share("charram");
map(0x2000, 0x27ff).ram().share("cgram");
}
void mt420_state::attrs_map(address_map &map)
{
map(0x0000, 0x0fff).ram().share("attrram");
}
static INPUT_PORTS_START(mt420)
@ -83,6 +128,7 @@ void mt420_state::mt420(machine_config &config)
m_maincpu->set_addrmap(AS_IO, &mt420_state::io_map);
INPUT_MERGER_ANY_HIGH(config, "mainint").output_handler().set_inputline(m_maincpu, 0);
INPUT_MERGER_ALL_HIGH(config, m_mainnmi).output_handler().set_inputline(m_maincpu, INPUT_LINE_NMI);
scn2681_device &duart(SCN2681(config, "duart", 3.6864_MHz_XTAL)); // MC2681
duart.irq_cb().set("mainint", FUNC(input_merger_device::in_w<0>));
@ -96,15 +142,18 @@ void mt420_state::mt420(machine_config &config)
EEPROM_93C46_16BIT(config, "eeprom").do_callback().set("duart", FUNC(scn2681_device::ip6_w));
screen_device &screen(SCREEN(config, "screen", SCREEN_TYPE_RASTER));
screen.set_raw(9.87768_MHz_XTAL, 612, 0, 480, 269, 0, 250);
//screen.set_raw(15.30072_MHz_XTAL, 948, 0, 792, 269, 0, 250);
screen.set_raw(9.87768_MHz_XTAL * 2, 612 * 2, 0, 480 * 2, 269, 0, 250);
//screen.set_raw(15.30072_MHz_XTAL * 2, 948 * 2, 0, 792 * 2, 269, 0, 250);
screen.set_screen_update("avdc", FUNC(scn2674_device::screen_update));
scn2674_device &avdc(SCN2674(config, "avdc", 9.87768_MHz_XTAL / 6));
//avdc.set_clock(15.30072_MHz_XTAL / 6);
avdc.set_character_width(6);
avdc.set_character_width(12);
avdc.intr_callback().set(m_mainnmi, FUNC(input_merger_device::in_w<0>));
avdc.intr_callback().append(FUNC(mt420_state::avdc_intr_w));
avdc.set_display_callback(FUNC(mt420_state::draw_character));
avdc.set_addrmap(0, &mt420_state::vram_map);
avdc.set_addrmap(0, &mt420_state::chars_map);
avdc.set_addrmap(1, &mt420_state::attrs_map);
avdc.set_screen("screen");
}