static int sfx_sh_irq_callback(int irqline)
{
/* interrupt acknowledge clears the flip-flop --
we need to pulse the CLR line because MAME's core never clears this
line, only asserts it */
TTL7474_clear_w(3, 0);
TTL7474_update(3);
TTL7474_clear_w(3, 1);
TTL7474_update(3);
return 0xff;
}
static void galaxian_7474_9M_2_callback(void)
{
/* Q bar clocks the other flip-flop,
Q is VBLANK (not visible to the CPU) */
TTL7474_clock_w(1, TTL7474_output_comp_r(0));
TTL7474_update(1);
}
static TIMER_CALLBACK( interrupt_timer )
{
/* 128V, 64V and 32V go to D */
TTL7474_d_w(0, (param & 0xe0) != 0xe0);
/* 16V clocks the flip-flop */
TTL7474_clock_w(0, param & 0x10);
param = (param + 0x10) & 0xff;
timer_adjust(int_timer, video_screen_get_time_until_pos(0, param, 0), param, attotime_zero);
TTL7474_update(0);
}
static void interrupt_timer(int param)
{
/* 128V, 64V and 32V go to D */
TTL7474_d_w(0, (param & 0xe0) != 0xe0);
/* 16V clocks the flip-flop */
TTL7474_clock_w(0, param & 0x10);
param = (param + 0x10) & 0xff;
timer_adjust(int_timer, cpu_getscanlinetime(param), param, 0);
TTL7474_update(0);
}
static WRITE8_HANDLER( pia_0_port_a_w )
{
/* bit 0 - Coin counter
bit 1 - Player 4 crash sound
bit 2 - Player 3 crash sound
bit 3 - Clear steering wheel logic
bit 4 - Player 2 crash sound
bit 5 - Score pulse sound
bit 6 - Player 1 crash sound
bit 7 - Ball hit pulse sound */
coin_counter_w(0, data & 0x01);
TTL7474_clear_w(TTL7474_1F_1, data & 0x08);
TTL7474_clear_w(TTL7474_1D_1, data & 0x08);
TTL7474_clear_w(TTL7474_1C_1, data & 0x08);
TTL7474_clear_w(TTL7474_1A_1, data & 0x08);
TTL7474_update(TTL7474_1F_1);
TTL7474_update(TTL7474_1D_1);
TTL7474_update(TTL7474_1C_1);
TTL7474_update(TTL7474_1A_1);
}
static WRITE8_HANDLER( coin4_interrupt_clear_w )
{
TTL7474_clear_w(TTL7474_2U_2, data);
TTL7474_update(TTL7474_2U_2);
}
static WRITE8_HANDLER( coin1_interrupt_clear_w )
{
TTL7474_clear_w(TTL7474_2S_1, data);
TTL7474_update(TTL7474_2S_1);
}