// license:BSD-3-Clause // copyright-holders:Phil Stroffolino /*************************************************************************** machine.c Functions to emulate general aspects of the machine (RAM, ROM, interrupts, I/O ports) ***************************************************************************/ #include "emu.h" #include "includes/lkage.h" /*************************************************************************** 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. ***************************************************************************/ READ8_MEMBER(lkage_state::lkage_68705_port_a_r) { //logerror("%04x: 68705 port A read %02x\n", space.device().safe_pc(), m_port_a_in); return (m_port_a_out & m_ddr_a) | (m_port_a_in & ~m_ddr_a); } WRITE8_MEMBER(lkage_state::lkage_68705_port_a_w) { //logerror("%04x: 68705 port A write %02x\n", space.device().safe_pc(), data); m_port_a_out = data; } WRITE8_MEMBER(lkage_state::lkage_68705_ddr_a_w) { m_ddr_a = 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 */ READ8_MEMBER(lkage_state::lkage_68705_port_b_r) { return (m_port_b_out & m_ddr_b) | (m_port_b_in & ~m_ddr_b); } WRITE8_MEMBER(lkage_state::lkage_68705_port_b_w) { //logerror("%04x: 68705 port B write %02x\n", space.device().safe_pc(), data); if ((m_ddr_b & 0x02) && (~data & 0x02) && (m_port_b_out & 0x02)) { m_port_a_in = m_from_main; if (m_main_sent) m_mcu->set_input_line(0, CLEAR_LINE); m_main_sent = 0; logerror("read command %02x from main cpu\n", m_port_a_in); } if ((m_ddr_b & 0x04) && (data & 0x04) && (~m_port_b_out & 0x04)) { logerror("send command %02x to main cpu\n", m_port_a_out); m_from_mcu = m_port_a_out; m_mcu_sent = 1; } m_port_b_out = data; } WRITE8_MEMBER(lkage_state::lkage_68705_ddr_b_w) { m_ddr_b = data; } READ8_MEMBER(lkage_state::lkage_68705_port_c_r) { m_port_c_in = 0; if (m_main_sent) m_port_c_in |= 0x01; if (!m_mcu_sent) m_port_c_in |= 0x02; //logerror("%04x: 68705 port C read %02x\n", space.device().safe_pc(), m_port_c_in); return (m_port_c_out & m_ddr_c) | (m_port_c_in & ~m_ddr_c); } WRITE8_MEMBER(lkage_state::lkage_68705_port_c_w) { logerror("%04x: 68705 port C write %02x\n", space.device().safe_pc(), data); m_port_c_out = data; } WRITE8_MEMBER(lkage_state::lkage_68705_ddr_c_w) { m_ddr_c = data; } WRITE8_MEMBER(lkage_state::lkage_mcu_w) { logerror("%04x: mcu_w %02x\n", space.device().safe_pc(), data); m_from_main = data; m_main_sent = 1; m_mcu->set_input_line(0, ASSERT_LINE); } READ8_MEMBER(lkage_state::lkage_mcu_r) { logerror("%04x: mcu_r %02x\n", space.device().safe_pc(), m_from_mcu); m_mcu_sent = 0; return m_from_mcu; } READ8_MEMBER(lkage_state::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", space.device().safe_pc()); if (!m_main_sent) res |= 0x01; if (m_mcu_sent) res |= 0x02; return res; }