diff options
Diffstat (limited to 'src/mame/machine/lkage.c')
-rw-r--r-- | src/mame/machine/lkage.c | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/src/mame/machine/lkage.c b/src/mame/machine/lkage.c new file mode 100644 index 00000000000..da03af1a1f4 --- /dev/null +++ b/src/mame/machine/lkage.c @@ -0,0 +1,139 @@ +/*************************************************************************** + + 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; +} |