summaryrefslogtreecommitdiffstatshomepage
path: root/src/mame/drivers/d6800.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/mame/drivers/d6800.c')
-rw-r--r--src/mame/drivers/d6800.c435
1 files changed, 435 insertions, 0 deletions
diff --git a/src/mame/drivers/d6800.c b/src/mame/drivers/d6800.c
new file mode 100644
index 00000000000..29f9a074051
--- /dev/null
+++ b/src/mame/drivers/d6800.c
@@ -0,0 +1,435 @@
+// license:BSD-3-Clause
+// copyright-holders:Robbbert
+/********************************************************************************
+
+ The Dream 6800 is a CHIP-8 computer roughly modelled on the Cosmac VIP.
+ It was described in Electronics Australia magazine in 4 articles starting
+ in May 1979. It has 1k of ROM and 1k of RAM. The video consists of 64x32
+ pixels. The keyboard is a hexcode 4x4 matrix, plus a Function key.
+
+ Designed by Michael Bauer, of the Division of Computing and Mathematics
+ at Deakin University, Australia.
+
+ NOTE that the display only updates after each 4 digits is entered, and
+ you can't see what you type as you change bytes. This is by design.
+
+ The cassette has no checksum, header or blocks. It is simply a stream
+ of pulses. The successful loading of a tape is therefore a matter of luck.
+
+ Function keys:
+ FN 0 - Modify memory - firstly enter a 4-digit address, then 2-digit data
+ the address will increment by itself, enter the next byte.
+ FN by itself will step to the next address.
+
+ FN 1 - Tape load. You must have entered the start address at 0002, and
+ the end address+1 at 0004 (big-endian).
+
+ FN 2 - Tape save. You must have entered the start address at 0002, and
+ the end address+1 at 0004 (big-endian).
+
+ FN 3 - Run. You must have entered the 4-digit go address first.
+
+ All CHIP-8 programs load at 0x200 (max size 4k), and exec address
+ is C000.
+
+ Information and programs can be found at http://chip8.com/?page=78
+
+
+**********************************************************************************/
+
+
+#include "emu.h"
+#include "cpu/m6800/m6800.h"
+#include "sound/beep.h"
+#include "imagedev/cassette.h"
+#include "imagedev/snapquik.h"
+#include "sound/wave.h"
+#include "machine/6821pia.h"
+
+
+class d6800_state : public driver_device
+{
+public:
+ d6800_state(const machine_config &mconfig, device_type type, const char *tag)
+ : driver_device(mconfig, type, tag),
+ m_maincpu(*this, "maincpu"),
+ m_cass(*this, "cassette"),
+ m_pia(*this, "pia"),
+ m_beeper(*this, "beeper"),
+ m_videoram(*this, "videoram"),
+ m_io_x0(*this, "X0"),
+ m_io_x1(*this, "X1"),
+ m_io_x2(*this, "X2"),
+ m_io_x3(*this, "X3"),
+ m_io_y0(*this, "Y0"),
+ m_io_y1(*this, "Y1"),
+ m_io_y2(*this, "Y2"),
+ m_io_y3(*this, "Y3"),
+ m_io_shift(*this, "SHIFT") { }
+
+ DECLARE_READ8_MEMBER( d6800_cassette_r );
+ DECLARE_WRITE8_MEMBER( d6800_cassette_w );
+ DECLARE_READ8_MEMBER( d6800_keyboard_r );
+ DECLARE_WRITE8_MEMBER( d6800_keyboard_w );
+ DECLARE_WRITE_LINE_MEMBER( d6800_screen_w );
+ UINT32 screen_update_d6800(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect);
+ TIMER_DEVICE_CALLBACK_MEMBER(d6800_c);
+ TIMER_DEVICE_CALLBACK_MEMBER(d6800_p);
+ DECLARE_QUICKLOAD_LOAD_MEMBER( d6800 );
+protected:
+ required_device<cpu_device> m_maincpu;
+ required_device<cassette_image_device> m_cass;
+ required_device<pia6821_device> m_pia;
+ required_device<beep_device> m_beeper;
+ required_shared_ptr<UINT8> m_videoram;
+ required_ioport m_io_x0;
+ required_ioport m_io_x1;
+ required_ioport m_io_x2;
+ required_ioport m_io_x3;
+ required_ioport m_io_y0;
+ required_ioport m_io_y1;
+ required_ioport m_io_y2;
+ required_ioport m_io_y3;
+ required_ioport m_io_shift;
+private:
+ UINT8 m_rtc;
+ bool m_cb2;
+ bool m_cassold;
+ UINT8 m_cass_data[4];
+ UINT8 m_portb;
+ virtual void machine_start();
+ virtual void machine_reset();
+};
+
+
+/* Memory Maps */
+
+static ADDRESS_MAP_START( d6800_map, AS_PROGRAM, 8, d6800_state )
+ AM_RANGE(0x0000, 0x00ff) AM_RAM
+ AM_RANGE(0x0100, 0x01ff) AM_RAM AM_SHARE("videoram")
+ AM_RANGE(0x0200, 0x0fff) AM_RAM
+ AM_RANGE(0x8010, 0x8013) AM_DEVREADWRITE("pia", pia6821_device, read, write)
+ AM_RANGE(0xc000, 0xc7ff) AM_MIRROR(0x3800) AM_ROM
+ADDRESS_MAP_END
+
+/* Input Ports */
+
+static INPUT_PORTS_START( d6800 )
+ PORT_START("X0")
+ PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_0) PORT_CHAR('0')
+ PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_1) PORT_CHAR('1')
+ PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_2) PORT_CHAR('2')
+ PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_3) PORT_CHAR('3')
+ PORT_BIT( 0xf0, IP_ACTIVE_LOW, IPT_UNUSED )
+
+ PORT_START("X1")
+ PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_4) PORT_CHAR('4')
+ PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_5) PORT_CHAR('5')
+ PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_6) PORT_CHAR('6')
+ PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_7) PORT_CHAR('7')
+ PORT_BIT( 0xf0, IP_ACTIVE_LOW, IPT_UNUSED )
+
+ PORT_START("X2")
+ PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_8) PORT_CHAR('8')
+ PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_9) PORT_CHAR('9')
+ PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_A) PORT_CHAR('A')
+ PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_B) PORT_CHAR('B')
+ PORT_BIT( 0xf0, IP_ACTIVE_LOW, IPT_UNUSED )
+
+ PORT_START("X3")
+ PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_C) PORT_CHAR('C')
+ PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_D) PORT_CHAR('D')
+ PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_E) PORT_CHAR('E')
+ PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_F) PORT_CHAR('F')
+ PORT_BIT( 0xf0, IP_ACTIVE_LOW, IPT_UNUSED )
+
+ PORT_START("Y0")
+ PORT_BIT( 0x0f, IP_ACTIVE_LOW, IPT_UNUSED )
+ PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_0) PORT_CHAR('0')
+ PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_4) PORT_CHAR('4')
+ PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_8) PORT_CHAR('8')
+ PORT_BIT( 0x80, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_C) PORT_CHAR('C')
+
+ PORT_START("Y1")
+ PORT_BIT( 0x0f, IP_ACTIVE_LOW, IPT_UNUSED )
+ PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_1) PORT_CHAR('1')
+ PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_5) PORT_CHAR('5')
+ PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_9) PORT_CHAR('9')
+ PORT_BIT( 0x80, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_D) PORT_CHAR('D')
+
+ PORT_START("Y2")
+ PORT_BIT( 0x0f, IP_ACTIVE_LOW, IPT_UNUSED )
+ PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_2) PORT_CHAR('2')
+ PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_6) PORT_CHAR('6')
+ PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_A) PORT_CHAR('A')
+ PORT_BIT( 0x80, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_E) PORT_CHAR('E')
+
+ PORT_START("Y3")
+ PORT_BIT( 0x0f, IP_ACTIVE_LOW, IPT_UNUSED )
+ PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_3) PORT_CHAR('3')
+ PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_7) PORT_CHAR('7')
+ PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_B) PORT_CHAR('B')
+ PORT_BIT( 0x80, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_CODE(KEYCODE_F) PORT_CHAR('F')
+
+ PORT_START("SHIFT")
+ PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_KEYBOARD ) PORT_NAME("FN") PORT_CODE(KEYCODE_LSHIFT)
+
+ PORT_START("VS")
+ /* vblank */
+ PORT_BIT(0x01, IP_ACTIVE_HIGH, IPT_CUSTOM) PORT_VBLANK("screen")
+INPUT_PORTS_END
+
+/* Video */
+
+UINT32 d6800_state::screen_update_d6800(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect)
+{
+ UINT8 x,y,gfx=0;
+
+ for (y = 0; y < 32; y++)
+ {
+ UINT16 *p = &bitmap.pix16(y);
+
+ for (x = 0; x < 8; x++)
+ {
+ if (m_cb2)
+ gfx = m_videoram[ x | (y<<3)];
+
+ *p++ = BIT(gfx, 7);
+ *p++ = BIT(gfx, 6);
+ *p++ = BIT(gfx, 5);
+ *p++ = BIT(gfx, 4);
+ *p++ = BIT(gfx, 3);
+ *p++ = BIT(gfx, 2);
+ *p++ = BIT(gfx, 1);
+ *p++ = BIT(gfx, 0);
+ }
+ }
+ return 0;
+}
+
+/* NE556 */
+
+TIMER_DEVICE_CALLBACK_MEMBER(d6800_state::d6800_c)
+{
+ m_cass_data[3]++;
+
+ if (BIT(m_portb, 0) != m_cassold)
+ {
+ m_cass_data[3] = 0;
+ m_cassold = BIT(m_portb, 0);
+ }
+
+ if (BIT(m_portb, 0))
+ m_cass->output(BIT(m_cass_data[3], 0) ? -1.0 : +1.0); // 2400Hz
+ else
+ m_cass->output(BIT(m_cass_data[3], 1) ? -1.0 : +1.0); // 1200Hz
+}
+
+/* PIA6821 Interface */
+
+TIMER_DEVICE_CALLBACK_MEMBER(d6800_state::d6800_p)
+{
+ m_rtc++;
+ if (m_rtc > 159)
+ m_rtc = 0;
+
+ UINT8 data = m_io_x0->read() & m_io_x1->read() & m_io_x2->read() & m_io_x3->read();
+ int ca1 = (data == 255) ? 0 : 1;
+ int ca2 = m_io_shift->read();
+ int cb1 = (m_rtc) ? 1 : 0;
+
+ m_pia->ca1_w(ca1);
+ m_pia->ca2_w(ca2);
+ m_pia->cb1_w(cb1);
+
+ /* cassette - turn 1200/2400Hz to a bit */
+ m_cass_data[1]++;
+ UINT8 cass_ws = (m_cass->input() > +0.03) ? 1 : 0;
+
+ if (cass_ws != m_cass_data[0])
+ {
+ m_cass_data[0] = cass_ws;
+ m_cass_data[2] = ((m_cass_data[1] < 12) ? 128 : 0);
+ m_cass_data[1] = 0;
+ }
+}
+
+
+WRITE_LINE_MEMBER( d6800_state::d6800_screen_w )
+{
+ m_cb2 = state;
+}
+
+READ8_MEMBER( d6800_state::d6800_cassette_r )
+{
+ /*
+ Cassette circuit consists of a 741 op-amp, a 74121 oneshot, and a 74LS74.
+ When a pulse arrives, the oneshot is set. After a preset time, it triggers
+ and the 74LS74 compares this pulse to the output of the 741. Therefore it
+ knows if the tone is 1200 or 2400 Hz. Input to PIA is bit 7.
+ */
+
+ return m_cass_data[2] | m_portb;
+}
+
+WRITE8_MEMBER( d6800_state::d6800_cassette_w )
+{
+ /*
+ A NE556 runs at either 1200 or 2400 Hz, depending on the state of bit 0.
+ This output drives the speaker and the output signal to the cassette player.
+ Bit 6 enables the speaker. Also the speaker is silenced when cassette operations
+ are in progress (DMA/CB2 line low).
+ */
+
+ m_beeper->set_frequency(BIT(data, 0) ? 2400 : 1200);
+ m_beeper->set_state(BIT(data, 6) & m_cb2);
+
+ m_portb = data & 0x7f;
+}
+
+READ8_MEMBER( d6800_state::d6800_keyboard_r )
+{
+ /*
+ This system reads the key matrix one way, then swaps the input and output
+ lines around and reads it another way. This isolates the key that was pressed.
+ */
+
+ UINT8 data = m_io_x0->read() & m_io_x1->read() & m_io_x2->read() & m_io_x3->read()
+ & m_io_y0->read() & m_io_y1->read() & m_io_y2->read() & m_io_y3->read();
+
+ return data;
+}
+
+WRITE8_MEMBER( d6800_state::d6800_keyboard_w )
+{
+ /*
+
+ bit description
+
+ PA0 keyboard column 0
+ PA1 keyboard column 1
+ PA2 keyboard column 2
+ PA3 keyboard column 3
+ PA4 keyboard row 0
+ PA5 keyboard row 1
+ PA6 keyboard row 2
+ PA7 keyboard row 3
+
+ */
+
+}
+
+/* Machine Initialization */
+
+void d6800_state::machine_start()
+{
+}
+
+void d6800_state::machine_reset()
+{
+ m_beeper->set_state(0);
+ m_rtc = 0;
+ m_cass_data[0] = 0;
+ m_cass_data[1] = 0;
+ m_cass_data[2] = 128;
+ m_cass_data[3] = 0;
+}
+
+/* Machine Drivers */
+
+QUICKLOAD_LOAD_MEMBER( d6800_state, d6800 )
+{
+ address_space &space = m_maincpu->space(AS_PROGRAM);
+ int i;
+ int quick_addr = 0x200;
+ int exec_addr = 0xc000;
+ int quick_length;
+ dynamic_buffer quick_data;
+ int read_;
+ int result = IMAGE_INIT_FAIL;
+
+ quick_length = image.length();
+ quick_data.resize(quick_length);
+ read_ = image.fread( &quick_data[0], quick_length);
+ if (read_ != quick_length)
+ {
+ image.seterror(IMAGE_ERROR_INVALIDIMAGE, "Cannot read the file");
+ image.message(" Cannot read the file");
+ }
+ else
+ {
+ for (i = 0; i < quick_length; i++)
+ if ((quick_addr + i) < 0x1000)
+ space.write_byte(i + quick_addr, quick_data[i]);
+
+ /* display a message about the loaded quickload */
+ image.message(" Quickload: size=%04X : start=%04X : end=%04X : exec=%04X",quick_length,quick_addr,quick_addr+quick_length,exec_addr);
+
+ // Start the quickload
+ if (strcmp(image.filetype(), "bin") == 0)
+ m_maincpu->set_pc(quick_addr);
+ else
+ m_maincpu->set_pc(exec_addr);
+
+ result = IMAGE_INIT_PASS;
+ }
+
+ return result;
+}
+
+static MACHINE_CONFIG_START( d6800, d6800_state )
+ /* basic machine hardware */
+ MCFG_CPU_ADD("maincpu",M6800, XTAL_4MHz/4)
+ MCFG_CPU_PROGRAM_MAP(d6800_map)
+
+ /* video hardware */
+ MCFG_SCREEN_ADD("screen", RASTER)
+ MCFG_SCREEN_REFRESH_RATE(50)
+ MCFG_SCREEN_SIZE(64, 32)
+ MCFG_SCREEN_VISIBLE_AREA(0, 63, 0, 31)
+ MCFG_SCREEN_UPDATE_DRIVER(d6800_state, screen_update_d6800)
+ MCFG_SCREEN_VBLANK_TIME(ATTOSECONDS_IN_USEC(25))
+ MCFG_SCREEN_PALETTE("palette")
+
+ MCFG_PALETTE_ADD_BLACK_AND_WHITE("palette")
+
+ /* sound hardware */
+ MCFG_SPEAKER_STANDARD_MONO("mono")
+ MCFG_SOUND_WAVE_ADD(WAVE_TAG, "cassette")
+ MCFG_SOUND_ROUTE(ALL_OUTPUTS, "mono", 0.50)
+ MCFG_SOUND_ADD("beeper", BEEP, 0)
+ MCFG_SOUND_ROUTE(ALL_OUTPUTS, "mono", 0.50)
+
+ /* devices */
+ MCFG_DEVICE_ADD("pia", PIA6821, 0)
+ MCFG_PIA_READPA_HANDLER(READ8(d6800_state, d6800_keyboard_r))
+ MCFG_PIA_READPB_HANDLER(READ8(d6800_state, d6800_cassette_r))
+ MCFG_PIA_WRITEPA_HANDLER(WRITE8(d6800_state, d6800_keyboard_w))
+ MCFG_PIA_WRITEPB_HANDLER(WRITE8(d6800_state, d6800_cassette_w))
+ MCFG_PIA_CB2_HANDLER(WRITELINE(d6800_state, d6800_screen_w))
+ MCFG_PIA_IRQA_HANDLER(DEVWRITELINE("maincpu", m6800_cpu_device, irq_line))
+ MCFG_PIA_IRQB_HANDLER(DEVWRITELINE("maincpu", m6800_cpu_device, irq_line))
+
+ MCFG_CASSETTE_ADD("cassette")
+ MCFG_CASSETTE_DEFAULT_STATE(CASSETTE_STOPPED | CASSETTE_MOTOR_ENABLED | CASSETTE_SPEAKER_MUTED)
+
+ MCFG_TIMER_DRIVER_ADD_PERIODIC("d6800_c", d6800_state, d6800_c, attotime::from_hz(4800))
+ MCFG_TIMER_DRIVER_ADD_PERIODIC("d6800_p", d6800_state, d6800_p, attotime::from_hz(40000))
+
+ /* quickload */
+ MCFG_QUICKLOAD_ADD("quickload", d6800_state, d6800, "bin,c8,ch8", 1)
+MACHINE_CONFIG_END
+
+/* ROMs */
+
+ROM_START( d6800 )
+ ROM_REGION( 0x10000, "maincpu", 0 )
+ ROM_SYSTEM_BIOS(0, "0", "Original")
+ ROMX_LOAD( "d6800.bin", 0xc000, 0x0400, CRC(3f97ca2e) SHA1(60f26e57a058262b30befceceab4363a5d65d877), ROM_BIOS(1) )
+ ROMX_LOAD( "d6800.bin", 0xc400, 0x0400, CRC(3f97ca2e) SHA1(60f26e57a058262b30befceceab4363a5d65d877), ROM_BIOS(1) )
+ ROM_SYSTEM_BIOS(1, "1", "Dreamsoft")
+ ROMX_LOAD( "d6800d.bin", 0xc000, 0x0800, CRC(ded5712f) SHA1(f594f313a74d7135c9fdd0bcb0093fc5771a9b7d), ROM_BIOS(2) )
+ROM_END
+
+/* YEAR NAME PARENT COMPAT MACHINE INPUT CLASS, INIT COMPANY FULLNAME FLAGS */
+COMP( 1979, d6800, 0, 0, d6800, d6800, driver_device, 0, "Michael Bauer", "Dream 6800", 0 )