/*************************************************************************** Sega Zaxxon hardware **************************************************************************** Sound interface is provided by an 8255. The 8255 is a parallel peripheral interface, used also in Scramble. It has three 8-bit outputs. All sounds are generated by discrete circuits. Each sound is triggered by an output pin of the 8255. Zaxxon Sound Information: (from the schematics) by Frank Palazzolo There are four registers in the 8255. they are mapped to (111x xxxx 0011 11pp) by Zaxxon. Zaxxon writes to these at FF3C-FF3F. There are three modes of the 8255, but by the schematics I can see that Zaxxon is using "Mode 0", which is very simple. Important Note: These are all Active-Low outputs. A 1 De-activates the sound, while a 0 Activates/Triggers it Port A Output: FF3C bit7 Battleship bit6 Laser bit5 Base Missle bit4 Homing Missle bit3 Player Ship D bit2 Player Ship C bit1 Player Ship B bit0 Player Ship A Port B Output: FF3D bit7 Cannon bit6 N/C bit5 M-Exp bit4 S-Exp bit3 N/C bit2 N/C bit1 N/C bit0 N/C Port C Output: FF3E bit7 N/C bit6 N/C bit5 N/C bit4 N/C bit3 Alarm 3 bit2 Alarm 2 bit1 N/C bit0 Shot Control Byte: FF3F Should be written an 0x80 for Mode 0 (Very Simple) operation of the 8255 ***************************************************************************/ #include "driver.h" #include "sound/samples.h" #include "includes/zaxxon.h" /************************************* * * Local sound states * *************************************/ static UINT8 sound_state[3]; /************************************* * * Zaxxon sound hardware description * *************************************/ static const char *zaxxon_sample_names[] = { "*zaxxon", "03.wav", /* 0 - Homing Missile */ "02.wav", /* 1 - Base Missile */ "01.wav", /* 2 - Laser (force field) */ "00.wav", /* 3 - Battleship (end of level boss) */ "11.wav", /* 4 - S-Exp (enemy explosion) */ "10.wav", /* 5 - M-Exp (ship explosion) */ "08.wav", /* 6 - Cannon (ship fire) */ "23.wav", /* 7 - Shot (enemy fire) */ "21.wav", /* 8 - Alarm 2 (target lock) */ "20.wav", /* 9 - Alarm 3 (low fuel) */ "05.wav", /* 10 - initial background noise */ "04.wav", /* 11 - looped asteroid noise */ 0 }; static struct Samplesinterface zaxxon_samples_interface = { 12, zaxxon_sample_names }; MACHINE_DRIVER_START( zaxxon_samples ) MDRV_SOUND_ADD(SAMPLES, 0) MDRV_SOUND_CONFIG(zaxxon_samples_interface) MDRV_SOUND_ROUTE(ALL_OUTPUTS, "mono", 0.25) MACHINE_DRIVER_END /************************************* * * Zaxxon PPI write handlers * *************************************/ WRITE8_HANDLER( zaxxon_sound_a_w ) { UINT8 diff = data ^ sound_state[0]; sound_state[0] = data; /* PLAYER SHIP A/B: volume */ sample_set_volume(10, 0.5 + 0.157 * (data & 0x03)); sample_set_volume(11, 0.5 + 0.157 * (data & 0x03)); /* PLAYER SHIP C: channel 10 */ if ((diff & 0x04) && !(data & 0x04)) sample_start(10, 10, TRUE); if ((diff & 0x04) && (data & 0x04)) sample_stop(10); /* PLAYER SHIP D: channel 11 */ if ((diff & 0x08) && !(data & 0x08)) sample_start(11, 11, TRUE); if ((diff & 0x08) && (data & 0x08)) sample_stop(11); /* HOMING MISSILE: channel 0 */ if ((diff & 0x10) && !(data & 0x10)) sample_start(0, 0, TRUE); if ((diff & 0x10) && (data & 0x10)) sample_stop(0); /* BASE MISSILE: channel 1 */ if ((diff & 0x20) && !(data & 0x20)) sample_start(1, 1, FALSE); /* LASER: channel 2 */ if ((diff & 0x40) && !(data & 0x40)) sample_start(2, 2, TRUE); if ((diff & 0x40) && (data & 0x40)) sample_stop(2); /* BATTLESHIP: channel 3 */ if ((diff & 0x80) && !(data & 0x80)) sample_start(3, 3, TRUE); if ((diff & 0x80) && (data & 0x80)) sample_stop(3); } WRITE8_HANDLER( zaxxon_sound_b_w ) { UINT8 diff = data ^ sound_state[1]; sound_state[1] = data; /* S-EXP: channel 4 */ if ((diff & 0x10) && !(data & 0x10)) sample_start(4, 4, FALSE); /* M-EXP: channel 5 */ if ((diff & 0x20) && !(data & 0x20) && !sample_playing(5)) sample_start(5, 5, FALSE); /* CANNON: channel 6 */ if ((diff & 0x80) && !(data & 0x80)) sample_start(6, 6, FALSE); } WRITE8_HANDLER( zaxxon_sound_c_w ) { UINT8 diff = data ^ sound_state[2]; sound_state[2] = data; /* SHOT: channel 7 */ if ((diff & 0x01) && !(data & 0x01)) sample_start(7, 7, FALSE); /* ALARM2: channel 8 */ if ((diff & 0x04) && !(data & 0x04)) sample_start(8, 8, FALSE); /* ALARM3: channel 9 */ if ((diff & 0x08) && !(data & 0x08) && !sample_playing(9)) sample_start(9, 9, FALSE); } /************************************* * * Congo sound hardware description * *************************************/ static const char *congo_sample_names[] = { "*congo", "gorilla.wav", /* 0 */ "bass.wav", /* 1 */ "congal.wav", /* 2 */ "congah.wav", /* 3 */ "rim.wav", /* 4 */ 0 }; static struct Samplesinterface congo_samples_interface = { 5, /* 5 channels */ congo_sample_names }; MACHINE_DRIVER_START( congo_samples ) MDRV_SOUND_ADD(SAMPLES, 0) MDRV_SOUND_CONFIG(congo_samples_interface) MDRV_SOUND_ROUTE(ALL_OUTPUTS, "mono", 0.25) MACHINE_DRIVER_END /************************************* * * Congo PPI write handlers * *************************************/ WRITE8_HANDLER( congo_sound_b_w ) { UINT8 diff = data ^ sound_state[1]; sound_state[1] = data; /* bit 7 = mute */ /* GORILLA: channel 0 */ if ((diff & 0x02) && !(data & 0x02) && !sample_playing(0)) sample_start(0, 0, FALSE); } WRITE8_HANDLER( congo_sound_c_w ) { UINT8 diff = data ^ sound_state[2]; sound_state[2] = data; /* BASS DRUM: channel 1 */ if ((diff & 0x01) && !(data & 0x01)) sample_start(1, 1, FALSE); if ((diff & 0x01) && (data & 0x01)) sample_stop(1); /* CONGA (LOW): channel 2 */ if ((diff & 0x02) && !(data & 0x02)) sample_start(2, 2, FALSE); if ((diff & 0x02) && (data & 0x02)) sample_stop(2); /* CONGA (HIGH): channel 3 */ if ((diff & 0x04) && !(data & 0x04)) sample_start(3, 3, FALSE); if ((diff & 0x04) && (data & 0x04)) sample_stop(3); /* RIM: channel 4 */ if ((diff & 0x08) && !(data & 0x08)) sample_start(4, 4, FALSE); if ((diff & 0x08) && (data & 0x08)) sample_stop(4); }