diff options
Diffstat (limited to 'src/mess/machine/c64/super_explode.c')
-rw-r--r-- | src/mess/machine/c64/super_explode.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/src/mess/machine/c64/super_explode.c b/src/mess/machine/c64/super_explode.c new file mode 100644 index 00000000000..f73585870da --- /dev/null +++ b/src/mess/machine/c64/super_explode.c @@ -0,0 +1,126 @@ +/********************************************************************** + + Super Explode! cartridge emulation + + Copyright MESS Team. + Visit http://mamedev.org for licensing and usage restrictions. + +**********************************************************************/ + +#include "super_explode.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_SUPER_EXPLODE = &device_creator<c64_super_explode_cartridge_device>; + + + +//************************************************************************** +// LIVE DEVICE +//************************************************************************** + +//------------------------------------------------- +// c64_super_explode_cartridge_device - constructor +//------------------------------------------------- + +c64_super_explode_cartridge_device::c64_super_explode_cartridge_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) : + device_t(mconfig, C64_SUPER_EXPLODE, "C64 Super Explode! cartridge", tag, owner, clock, "c64_super_explode", __FILE__), + device_c64_expansion_card_interface(mconfig, *this) +{ +} + + +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void c64_super_explode_cartridge_device::device_start() +{ + // allocate timer + m_exrom_timer = timer_alloc(); + + // state saving + save_item(NAME(m_bank)); +} + + +//------------------------------------------------- +// device_reset - device-specific reset +//------------------------------------------------- + +void c64_super_explode_cartridge_device::device_reset() +{ + m_bank = 0; + + m_exrom = 0; + m_exrom_timer->adjust(attotime::from_usec(TIMER_PERIOD), 0); +} + + +//------------------------------------------------- +// device_timer - handler timer events +//------------------------------------------------- + +void c64_super_explode_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_super_explode_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[(m_bank << 13) | (offset & 0x1fff)]; + } + else if (!io1) + { + m_exrom = 0; + m_exrom_timer->adjust(attotime::from_usec(TIMER_PERIOD), 0); + } + else if (!io2) + { + data = m_roml[(m_bank << 13) | (offset & 0x1fff)]; + } + + return data; +} + + +//------------------------------------------------- +// c64_cd_w - cartridge data write +//------------------------------------------------- + +void c64_super_explode_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); + } + else if (!io2) + { + m_bank = BIT(data, 7); + } +} |