/********************************************************************** Epyx Fast Load cartridge emulation Copyright MESS Team. Visit http://mamedev.org for licensing and usage restrictions. **********************************************************************/ #include "c64_epyx_fast_load.h" //************************************************************************** // MACROS/CONSTANTS //************************************************************************** // t = R*C = 3.3K * 0.47uF * 40% Vtr = 792.2905424610516 usec // (3.3K pull-up on the EXROM line inside the C64, PLA Vih min = 2.0V = 40% of 5.0V) #define TIMER_PERIOD 792 //************************************************************************** // DEVICE DEFINITIONS //************************************************************************** const device_type C64_EPYX_FAST_LOAD = &device_creator; //************************************************************************** // LIVE DEVICE //************************************************************************** //------------------------------------------------- // c64_epyx_fast_load_cartridge_device - constructor //------------------------------------------------- c64_epyx_fast_load_cartridge_device::c64_epyx_fast_load_cartridge_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) : device_t(mconfig, C64_EPYX_FAST_LOAD, "C64 Epyx Fast Load cartridge", tag, owner, clock, "c64_epyx_fast_load", __FILE__), device_c64_expansion_card_interface(mconfig, *this) { } //------------------------------------------------- // device_start - device-specific startup //------------------------------------------------- void c64_epyx_fast_load_cartridge_device::device_start() { // allocate timer m_exrom_timer = timer_alloc(); } //------------------------------------------------- // device_reset - device-specific reset //------------------------------------------------- void c64_epyx_fast_load_cartridge_device::device_reset() { m_exrom = 0; m_exrom_timer->adjust(attotime::from_usec(TIMER_PERIOD), 0); } //------------------------------------------------- // device_timer - handler timer events //------------------------------------------------- void c64_epyx_fast_load_cartridge_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr) { m_exrom = 1; } //------------------------------------------------- // c64_cd_r - cartridge data read //------------------------------------------------- UINT8 c64_epyx_fast_load_cartridge_device::c64_cd_r(address_space &space, offs_t offset, UINT8 data, int sphi2, int ba, int roml, int romh, int io1, int io2) { if (!roml) { m_exrom = 0; m_exrom_timer->adjust(attotime::from_usec(TIMER_PERIOD), 0); data = m_roml[offset & 0x1fff]; } else if (!io1) { m_exrom = 0; m_exrom_timer->adjust(attotime::from_usec(TIMER_PERIOD), 0); } else if (!io2) { data = m_roml[offset & 0x1fff]; } return data; } //------------------------------------------------- // c64_cd_w - cartridge data write //------------------------------------------------- void c64_epyx_fast_load_cartridge_device::c64_cd_w(address_space &space, offs_t offset, UINT8 data, int sphi2, int ba, int roml, int romh, int io1, int io2) { if (!io1) { m_exrom = 0; m_exrom_timer->adjust(attotime::from_usec(TIMER_PERIOD), 0); } }