// license:BSD-3-Clause // copyright-holders:Nicola Salmoria /*************************************************************************** taitosj.cpp Functions to emulate general aspects of the machine (RAM, ROM, interrupts, I/O ports) ***************************************************************************/ #include "emu.h" #include "cpu/m6805/m6805.h" #include "includes/taitosj.h" #define VERBOSE 1 #define LOG(x) do { if (VERBOSE) logerror x; } while (0) void taitosj_state::machine_start() { m_mainbank->configure_entry(0, memregion("maincpu")->base() + 0x6000); m_mainbank->configure_entry(1, memregion("maincpu")->base() + 0x10000); save_item(NAME(m_spacecr_prot_value)); save_item(NAME(m_protection_value)); } void taitosj_state::machine_reset() { /* set the default ROM bank (many games only have one bank and never write to the bank selector register) */ bankswitch_w(0); m_spacecr_prot_value = 0; } void taitosj_state::bankswitch_w(uint8_t data) { machine().bookkeeping().coin_lockout_global_w(~data & 1); /* this is a bit of a hack, but works. Eventually the mixing of the ay1 outs and amplitude-overdrive-mute stuff done by bit 1 here should be done on a netlist. */ m_ay[0]->set_output_gain(0, (data & 0x2) ? 1.0 : 0.0); // 3 outputs for Ay1 since it doesn't use tied together outs m_ay[0]->set_output_gain(1, (data & 0x2) ? 1.0 : 0.0); m_ay[0]->set_output_gain(2, (data & 0x2) ? 1.0 : 0.0); m_ay[1]->set_output_gain(0, (data & 0x2) ? 1.0 : 0.0); m_ay[2]->set_output_gain(0, (data & 0x2) ? 1.0 : 0.0); m_ay[3]->set_output_gain(0, (data & 0x2) ? 1.0 : 0.0); m_dac->set_output_gain(0, (data & 0x2) ? 1.0 : 0.0); m_mainbank->set_entry(BIT(data, 7)); } /*************************************************************************** PROTECTION HANDLING Some of the games running on this hardware are protected with a 68705 mcu. It can either be on a daughter board containing Z80+68705+one ROM, which replaces the Z80 on an unprotected main board; or it can be built-in on the main board. The two are functionally equivalent. The 68705 can read commands from the Z80, send back result codes, and has direct access to the Z80 memory space. It can also trigger IRQs on the Z80. ***************************************************************************/ uint8_t taitosj_state::fake_data_r() { LOG(("%04x: protection read\n", m_maincpu->pc())); return 0; } void taitosj_state::fake_data_w(uint8_t data) { LOG(("%04x: protection write %02x\n", m_maincpu->pc(), data)); } uint8_t taitosj_state::fake_status_r() { LOG(("%04x: protection status read\n", m_maincpu->pc())); return 0xff; } uint8_t taitosj_state::mcu_mem_r(offs_t offset) { return m_maincpu->space(AS_PROGRAM).read_byte(offset); } void taitosj_state::mcu_mem_w(offs_t offset, uint8_t data) { m_maincpu->space(AS_PROGRAM).write_byte(offset, data); } WRITE_LINE_MEMBER(taitosj_state::mcu_intrq_w) { // FIXME: there's a logic network here that makes this edge sensitive or something and mixes it with other interrupt sources if (CLEAR_LINE != state) LOG(("68705 68INTRQ **NOT SUPPORTED**!\n")); } WRITE_LINE_MEMBER(taitosj_state::mcu_busrq_w) { // this actually goes to the Z80 BUSRQ (aka WAIT) pin, and the MCU waits for the bus to become available // we're pretending this happens immediately to make life easier m_mcu->busak_w(state); } // Space Cruiser protection (otherwise the game resets on the asteroids level) uint8_t taitosj_state::spacecr_prot_r() { int pc = m_maincpu->pc(); if( pc != 0x368A && pc != 0x36A6 ) logerror("Read protection from an unknown location: %04X\n",pc); m_spacecr_prot_value ^= 0xff; return m_spacecr_prot_value; } // Alpine Ski protection crack routines void taitosj_state::alpine_protection_w(uint8_t data) { switch (data) { case 0x05: m_protection_value = 0x18; break; case 0x07: case 0x0c: case 0x0f: m_protection_value = 0x00; // not used as far as I can tell break; case 0x16: m_protection_value = 0x08; break; case 0x1d: m_protection_value = 0x18; break; default: m_protection_value = data; // not used as far as I can tell break; } } void taitosj_state::alpinea_bankswitch_w(uint8_t data) { bankswitch_w(data); m_protection_value = data >> 2; } uint8_t taitosj_state::alpine_port_2_r() { return m_in2->read() | m_protection_value; }