// 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 "video/saa5050.h" #include "video/mc6845.h" #include "imagedev/cassette.h" #include "sound/wave.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") { } DECLARE_WRITE8_MEMBER(kbd_put); 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); required_shared_ptr m_p_videoram; UINT16 m_start_address; UINT16 m_cursor_address; private: UINT8 m_cass_data[4]; bool m_cass_state; bool m_cassold; UINT8 m_video_index; required_device m_via; required_device m_cass; required_device m_maincpu; required_device m_crtc; }; static ADDRESS_MAP_START(a6809_mem, AS_PROGRAM, 8, a6809_state) ADDRESS_MAP_UNMAP_HIGH AM_RANGE(0x0000,0x03ff) AM_RAM AM_RANGE(0x0400,0x07ff) AM_RAM AM_SHARE("videoram") AM_RANGE(0x0800,0x0800) AM_DEVREAD("mc6845", mc6845_device, status_r) AM_WRITE(a6809_address_w) AM_RANGE(0x0801,0x0801) AM_DEVREAD("mc6845", mc6845_device, register_r) AM_WRITE(a6809_register_w) AM_RANGE(0x0900,0x090f) AM_MIRROR(0xf0) AM_DEVREADWRITE("via", via6522_device, read, write) AM_RANGE(0xf000,0xf7ff) // optional ROM AM_RANGE(0xf800,0xffff) AM_ROM AM_REGION("maincpu", 0) ADDRESS_MAP_END static ADDRESS_MAP_START( a6809_io, AS_IO, 8, a6809_state) ADDRESS_MAP_UNMAP_HIGH ADDRESS_MAP_END /* 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 temp = m_start_address; UINT16 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 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; } } WRITE8_MEMBER( a6809_state::kbd_put ) { UINT8 d = data & 0x7f; if (d == 8) d = 0x7f; // allow backspace to work m_via->write_pb0((d>>0)&1); m_via->write_pb1((d>>1)&1); m_via->write_pb2((d>>2)&1); m_via->write_pb3((d>>3)&1); m_via->write_pb4((d>>4)&1); m_via->write_pb5((d>>5)&1); m_via->write_pb6((d>>6)&1); m_via->write_cb1(1); m_via->write_cb1(0); } static MACHINE_CONFIG_START( a6809, a6809_state ) /* basic machine hardware */ MCFG_CPU_ADD("maincpu",M6809E, XTAL_4MHz) MCFG_CPU_PROGRAM_MAP(a6809_mem) MCFG_CPU_IO_MAP(a6809_io) 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 */ MCFG_SPEAKER_STANDARD_MONO("mono") MCFG_SOUND_WAVE_ADD(WAVE_TAG, "cassette") MCFG_SOUND_ROUTE(ALL_OUTPUTS, "mono", 0.25) /* Devices */ MCFG_DEVICE_ADD("via", VIA6522, XTAL_4MHz / 4) MCFG_VIA6522_CB2_HANDLER(WRITELINE(a6809_state, cass_w)) MCFG_VIA6522_IRQ_HANDLER(DEVWRITELINE("maincpu", m6809e_device, irq_line)) MCFG_MC6845_ADD("mc6845", HD6845, "screen", XTAL_4MHz / 2) MCFG_MC6845_SHOW_BORDER_AREA(false) MCFG_MC6845_CHAR_WIDTH(12) MCFG_DEVICE_ADD("saa5050", SAA5050, 6000000) MCFG_SAA5050_D_CALLBACK(READ8(a6809_state, videoram_r)) MCFG_SAA5050_SCREEN_SIZE(40, 25, 40) MCFG_DEVICE_ADD("keyboard", GENERIC_KEYBOARD, 0) MCFG_GENERIC_KEYBOARD_CB(WRITE8(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, driver_device, 0, "Acorn", "System 3 (6809 CPU)", 0 )