/*************************************************************************** machine.c Functions to emulate general aspects of the machine (RAM, ROM, interrupts, I/O ports) ***************************************************************************/ #include "driver.h" static UINT8 from_main,from_mcu; static int mcu_sent = 0,main_sent = 0; /*************************************************************************** Legend of Kage 68705 protection interface The following is ENTIRELY GUESSWORK!!! And moreover, the game seems to work anyway regardless of what the mcu returns. ***************************************************************************/ static UINT8 portA_in,portA_out,ddrA; READ8_HANDLER( lkage_68705_portA_r ) { //logerror("%04x: 68705 port A read %02x\n",activecpu_get_pc(),portA_in); return (portA_out & ddrA) | (portA_in & ~ddrA); } WRITE8_HANDLER( lkage_68705_portA_w ) { //logerror("%04x: 68705 port A write %02x\n",activecpu_get_pc(),data); portA_out = data; } WRITE8_HANDLER( lkage_68705_ddrA_w ) { ddrA = data; } /* * Port B connections: * * all bits are logical 1 when read (+5V pullup) * * 1 W when 1->0, enables latch which brings the command from main CPU (read from port A) * 2 W when 0->1, copies port A to the latch for the main CPU */ static UINT8 portB_in,portB_out,ddrB; READ8_HANDLER( lkage_68705_portB_r ) { return (portB_out & ddrB) | (portB_in & ~ddrB); } WRITE8_HANDLER( lkage_68705_portB_w ) { //logerror("%04x: 68705 port B write %02x\n",activecpu_get_pc(),data); if ((ddrB & 0x02) && (~data & 0x02) && (portB_out & 0x02)) { portA_in = from_main; if (main_sent) cpunum_set_input_line(2,0,CLEAR_LINE); main_sent = 0; logerror("read command %02x from main cpu\n",portA_in); } if ((ddrB & 0x04) && (data & 0x04) && (~portB_out & 0x04)) { logerror("send command %02x to main cpu\n",portA_out); from_mcu = portA_out; mcu_sent = 1; } portB_out = data; } WRITE8_HANDLER( lkage_68705_ddrB_w ) { ddrB = data; } static UINT8 portC_in,portC_out,ddrC; READ8_HANDLER( lkage_68705_portC_r ) { portC_in = 0; if (main_sent) portC_in |= 0x01; if (!mcu_sent) portC_in |= 0x02; //logerror("%04x: 68705 port C read %02x\n",activecpu_get_pc(),portC_in); return (portC_out & ddrC) | (portC_in & ~ddrC); } WRITE8_HANDLER( lkage_68705_portC_w ) { logerror("%04x: 68705 port C write %02x\n",activecpu_get_pc(),data); portC_out = data; } WRITE8_HANDLER( lkage_68705_ddrC_w ) { ddrC = data; } WRITE8_HANDLER( lkage_mcu_w ) { logerror("%04x: mcu_w %02x\n",activecpu_get_pc(),data); from_main = data; main_sent = 1; cpunum_set_input_line(2,0,ASSERT_LINE); } READ8_HANDLER( lkage_mcu_r ) { logerror("%04x: mcu_r %02x\n",activecpu_get_pc(),from_mcu); mcu_sent = 0; return from_mcu; } READ8_HANDLER( lkage_mcu_status_r ) { int res = 0; /* bit 0 = when 1, mcu is ready to receive data from main cpu */ /* bit 1 = when 1, mcu has sent data to the main cpu */ //logerror("%04x: mcu_status_r\n",activecpu_get_pc()); if (!main_sent) res |= 0x01; if (mcu_sent) res |= 0x02; return res; }