// license:BSD-3-Clause // copyright-holders:Miodrag Milanovic, Robbbert /*************************************************************************** MITS Altair 680b 2009-12-03 Skeleton driver. 2011-06-08 Connected to a terminal Monitor Commands: J L switch to terminal mode M N modify memory in a limited way P this does a rti and causes a momentary crash. Weird. ToDo: ****************************************************************************/ #include "emu.h" #include "cpu/m6800/m6800.h" #include "machine/6850acia.h" #include "bus/rs232/rs232.h" #include "machine/clock.h" class mits680b_state : public driver_device { public: mits680b_state(const machine_config &mconfig, device_type type, const char *tag) : driver_device(mconfig, type, tag) , m_maincpu(*this, "maincpu") { } DECLARE_READ8_MEMBER(status_check_r); void mits680b(machine_config &config); void mem_map(address_map &map); private: required_device m_maincpu; }; READ8_MEMBER( mits680b_state::status_check_r ) { return 0; // crashes at start if bit 7 high } void mits680b_state::mem_map(address_map &map) { map.unmap_value_high(); map(0x0000, 0x03ff).ram(); // 1024 bytes RAM map(0xf000, 0xf001).rw("acia", FUNC(acia6850_device::read), FUNC(acia6850_device::write)); map(0xf002, 0xf002).r(this, FUNC(mits680b_state::status_check_r)); map(0xff00, 0xffff).rom().region("roms", 0); } /* Input ports */ static INPUT_PORTS_START( mits680b ) INPUT_PORTS_END MACHINE_CONFIG_START(mits680b_state::mits680b) /* basic machine hardware */ MCFG_DEVICE_ADD("maincpu", M6800, XTAL(1'000'000) / 2) MCFG_DEVICE_PROGRAM_MAP(mem_map) MCFG_DEVICE_ADD("uart_clock", CLOCK, 153600) MCFG_CLOCK_SIGNAL_HANDLER(WRITELINE("acia", acia6850_device, write_txc)) MCFG_DEVCB_CHAIN_OUTPUT(WRITELINE("acia", acia6850_device, write_rxc)) MCFG_DEVICE_ADD("acia", ACIA6850, 0) MCFG_ACIA6850_TXD_HANDLER(WRITELINE("rs232", rs232_port_device, write_txd)) MCFG_ACIA6850_RTS_HANDLER(WRITELINE("rs232", rs232_port_device, write_rts)) MCFG_DEVICE_ADD("rs232", RS232_PORT, default_rs232_devices, "terminal") MCFG_RS232_RXD_HANDLER(WRITELINE("acia", acia6850_device, write_rxd)) MCFG_RS232_CTS_HANDLER(WRITELINE("acia", acia6850_device, write_cts)) MACHINE_CONFIG_END /* ROM definition */ ROM_START( mits680b ) ROM_REGION( 0x100, "roms", ROMREGION_ERASEFF ) ROM_LOAD( "mits680b.bin", 0x0000, 0x0100, CRC(397e717f) SHA1(257d3eb1343b8611dc05455aeed33615d581f29c)) ROM_END /* Driver */ // YEAR NAME PARENT COMPAT MACHINE INPUT CLASS INIT COMPANY FULLNAME FLAGS COMP( 1976, mits680b, 0, 0, mits680b, mits680b, mits680b_state, empty_init, "MITS", "Altair 680b", MACHINE_NOT_WORKING | MACHINE_NO_SOUND)