// license:BSD-3-Clause // copyright-holders:Robbbert and unknown others /*************************************************************************** Acorn 6809 2009-05-12 Skeleton driver. 2013-12-16 Fixed video [Robbbert] Acorn System 3 update? http://acorn.chriswhy.co.uk/8bit_Upgrades/Acorn_6809_CPU.html This is a few boards emulated together: - 6809 main board - 80x25 video board - FDC board (to come) The video board has a mc6845, and the characters do not go to a character generator, instead they go to a SAA5050, which has its own CG inbuilt, plus many other features. ToDo: - FDC (address A00) - Centronics Printer (VIA port A) Commands: C - Echo to printer ( C '+' turns it on) D - boot from disk G - Go L - Load tape P - Run from pc reg R - Display regs S - Save tape T - Trace V - Set breakpoint M - Modify memory MV - Modify memory at breakpoint address MG - Modify memory from Go address MP - Modify memory from pc-reg address MR - Modify regs While modifying memory: , show next address - show previous address enter show next address ; exit ****************************************************************************/ #include "emu.h" #include "cpu/m6809/m6809.h" #include "machine/6522via.h" #include "machine/keyboard.h" #include "machine/timer.h" #include "video/saa5050.h" #include "video/mc6845.h" #include "imagedev/cassette.h" #include "sound/wave.h" #include "screen.h" #include "speaker.h" class a6809_state : public driver_device { public: a6809_state(const machine_config &mconfig, device_type type, const char *tag) : driver_device(mconfig, type, tag) , m_p_videoram(*this, "videoram") , m_via(*this, "via") , m_cass(*this, "cassette") , m_maincpu(*this, "maincpu") , m_crtc(*this, "mc6845") { } void a6809(machine_config &config); protected: void kbd_put(u8 data); DECLARE_READ8_MEMBER(videoram_r); DECLARE_WRITE8_MEMBER(a6809_address_w); DECLARE_WRITE8_MEMBER(a6809_register_w); DECLARE_WRITE_LINE_MEMBER(cass_w); DECLARE_MACHINE_RESET(a6809); TIMER_DEVICE_CALLBACK_MEMBER(a6809_c); TIMER_DEVICE_CALLBACK_MEMBER(a6809_p); void a6809_mem(address_map &map); private: required_shared_ptr m_p_videoram; uint16_t m_start_address; uint16_t m_cursor_address; uint8_t m_cass_data[4]; bool m_cass_state; bool m_cassold; uint8_t m_video_index; required_device m_via; required_device m_cass; required_device m_maincpu; required_device m_crtc; }; void a6809_state::a6809_mem(address_map &map) { map.unmap_value_high(); map(0x0000, 0x03ff).ram(); map(0x0400, 0x07ff).ram().share("videoram"); map(0x0800, 0x0800).r(m_crtc, FUNC(mc6845_device::status_r)).w(this, FUNC(a6809_state::a6809_address_w)); map(0x0801, 0x0801).r(m_crtc, FUNC(mc6845_device::register_r)).w(this, FUNC(a6809_state::a6809_register_w)); map(0x0900, 0x090f).mirror(0xf0).rw(m_via, FUNC(via6522_device::read), FUNC(via6522_device::write)); map(0xf000, 0xf7ff); // optional ROM map(0xf800, 0xffff).rom().region("maincpu", 0); } /* Input ports */ static INPUT_PORTS_START( a6809 ) INPUT_PORTS_END MACHINE_RESET_MEMBER( a6809_state, a6809) { m_via->write_pb0(0); m_via->write_pb1(0); m_via->write_pb2(0); m_via->write_pb3(0); m_via->write_pb4(0); m_via->write_pb5(0); m_via->write_pb6(0); m_via->write_pb7(0); } READ8_MEMBER( a6809_state::videoram_r ) { offset += m_start_address; if (m_cursor_address == offset) return 0x7f; // cheap cursor else return m_p_videoram[offset&0x3ff]; } WRITE8_MEMBER( a6809_state::a6809_address_w ) { m_crtc->address_w( space, 0, data ); m_video_index = data & 0x1f; } WRITE8_MEMBER( a6809_state::a6809_register_w ) { uint16_t temp = m_start_address; uint16_t temq = m_cursor_address; m_crtc->register_w( space, 0, data ); // Get start address if (m_video_index == 12) m_start_address = ((data & 7) << 8 ) | (temp & 0xff); else if (m_video_index == 13) m_start_address = data | (temp & 0x3f00); else // Get cursor address if (m_video_index == 14) m_cursor_address = ((data & 7) << 8 ) | (temq & 0xff); else if (m_video_index == 15) m_cursor_address = data | (temq & 0x3f00); } WRITE_LINE_MEMBER( a6809_state::cass_w ) { m_cass_state = state; } TIMER_DEVICE_CALLBACK_MEMBER(a6809_state::a6809_c) { m_cass_data[3]++; if (m_cass_state != m_cassold) { m_cass_data[3] = 0; m_cassold = m_cass_state; } if (m_cass_state) 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 } TIMER_DEVICE_CALLBACK_MEMBER(a6809_state::a6809_p) { /* cassette - turn 1200/2400Hz to a bit */ m_cass_data[1]++; uint8_t cass_ws = (m_cass->input() > +0.03) ? 1 : 0; if (cass_ws != m_cass_data[0]) { m_cass_data[0] = cass_ws; m_via->write_pb7(m_cass_data[1] < 12); m_cass_data[1] = 0; } } void a6809_state::kbd_put(u8 data) { uint8_t d = data & 0x7f; if (d == 8) d = 0x7f; // allow backspace to work m_via->write_pb0(BIT(d, 0)); m_via->write_pb1(BIT(d, 1)); m_via->write_pb2(BIT(d, 2)); m_via->write_pb3(BIT(d, 3)); m_via->write_pb4(BIT(d, 4)); m_via->write_pb5(BIT(d, 5)); m_via->write_pb6(BIT(d, 6)); m_via->write_cb1(1); m_via->write_cb1(0); } MACHINE_CONFIG_START(a6809_state::a6809) /* basic machine hardware */ MCFG_DEVICE_ADD("maincpu", MC6809, XTAL(4'000'000)) MCFG_DEVICE_PROGRAM_MAP(a6809_mem) MCFG_MACHINE_RESET_OVERRIDE(a6809_state, a6809) /* video hardware */ MCFG_SCREEN_ADD("screen", RASTER) MCFG_SCREEN_REFRESH_RATE(50) MCFG_SCREEN_VBLANK_TIME(ATTOSECONDS_IN_USEC(2500)) MCFG_SCREEN_SIZE(40 * 12, 25 * 20) MCFG_SCREEN_VISIBLE_AREA(0, 40 * 12 - 1, 0, 25 * 20 - 1) MCFG_SCREEN_UPDATE_DEVICE("saa5050", saa5050_device, screen_update) MCFG_PALETTE_ADD("palette", 8) /* sound hardware */ SPEAKER(config, "mono").front_center(); WAVE(config, "wave", "cassette").add_route(ALL_OUTPUTS, "mono", 0.25); /* Devices */ MCFG_DEVICE_ADD("via", VIA6522, XTAL(4'000'000) / 4) MCFG_VIA6522_CB2_HANDLER(WRITELINE(*this, a6809_state, cass_w)) MCFG_VIA6522_IRQ_HANDLER(INPUTLINE("maincpu", M6809_IRQ_LINE)) MCFG_MC6845_ADD("mc6845", HD6845, "screen", XTAL(4'000'000) / 2) MCFG_MC6845_SHOW_BORDER_AREA(false) MCFG_MC6845_CHAR_WIDTH(12) MCFG_DEVICE_ADD("saa5050", SAA5050, 6000000) MCFG_SAA5050_D_CALLBACK(READ8(*this, a6809_state, videoram_r)) MCFG_SAA5050_SCREEN_SIZE(40, 25, 40) MCFG_DEVICE_ADD("keyboard", GENERIC_KEYBOARD, 0) MCFG_GENERIC_KEYBOARD_CB(PUT(a6809_state, kbd_put)) MCFG_CASSETTE_ADD( "cassette" ) MCFG_TIMER_DRIVER_ADD_PERIODIC("a6809_c", a6809_state, a6809_c, attotime::from_hz(4800)) MCFG_TIMER_DRIVER_ADD_PERIODIC("a6809_p", a6809_state, a6809_p, attotime::from_hz(40000)) MACHINE_CONFIG_END /* ROM definition */ ROM_START( a6809 ) ROM_REGION( 0x800, "maincpu", 0 ) ROM_LOAD( "acorn6809.bin", 0x000, 0x800, CRC(5fa5b632) SHA1(b14a884bf82a7a8c23bc03c2e112728dd1a74896) ) ROM_REGION( 0x100, "proms", 0 ) ROM_LOAD( "acorn6809.ic11", 0x0000, 0x0100, CRC(7908317d) SHA1(e0f1e5bd3a8598d3b62bc432dd1f3892ed7e66d8) ) // address decoder ROM_END /* Driver */ /* YEAR NAME PARENT COMPAT MACHINE INPUT CLASS INIT COMPANY FULLNAME FLAGS */ COMP( 1980, a6809, 0, 0, a6809, a6809, a6809_state, empty_init, "Acorn", "System 3 (6809 CPU)", 0 )