void beep_set_volume(int num, int volume)
{
struct beep_sound *info = sndti_token(SOUND_BEEP, num);
stream_update(info->stream);
volume = 100 * volume / 7;
sndti_set_output_gain(SOUND_BEEP, num, 0, volume );
}
static WRITE8_HANDLER( ay8910_portA_0_w )
{
float percent;
/*There are three AY8910 chips and four(!) separate amplifiers on the board
* Each of AY channels is hardware mapped in following way:
* amplifier 0 gain x 1.00 <- AY0 CHA
* amplifier 1 gain x 1.00 <- AY0 CHB + AY0 CHC + AY1 CHA + AY1 CHB
* amplifier 2 gain x 4.54 (150K/33K) <- AY1 CHC + AY2 CHA
* amplifier 3 gain x 4.54 (150K/33K) <- AY2 CHB + AY2 CHC
*
* Each of the amps has its own analog cuircit:
* amp0, amp1 and amp2 are different from each other; amp3 is the same as amp2
*
* Outputs of those amps are inputs to post amps, each having own cuircit
* that is partially controlled by AY #0 port A.
* PORT A BIT 0 - control postamp 0 (gain x10.0 | gain x 5.00)
* PORT A BIT 1 - control postamp 1 (gain x4.54 | gain x 2.27)
* PORT A BIT 2 - control postamp 2 (gain x1.00 | gain x 0.50)
* PORT A BIT 3 - control postamp 3 (gain x1.00 | gain x 0.50)
*
* The "control" means assert/clear input pins on chip called 4066 (it is analog switch)
* which results in volume gain (exactly 2 times).
* I use mixer_set_volume() to emulate the effect.
gain summary:
port A control ON OFF
amp0 = *1*10.0=10.0 *1*5.0 = 5.0
amp1 = *1*4.54=4.54 *1*2.27 = 2.27
amp2 = *4.54*1=4.54 *4.54*0.5= 2.27
amp3 = *4.54*1=4.54 *4.54*0.5= 2.27
*/
/*
bit0 - SOUND Chan#0 name=AY-3-8910 #0 Ch A
bit1 - SOUND Chan#1 name=AY-3-8910 #0 Ch B
bit1 - SOUND Chan#2 name=AY-3-8910 #0 Ch C
bit1 - SOUND Chan#3 name=AY-3-8910 #1 Ch A
bit1 - SOUND Chan#4 name=AY-3-8910 #1 Ch B
bit2 - SOUND Chan#5 name=AY-3-8910 #1 Ch C
bit2 - SOUND Chan#6 name=AY-3-8910 #2 Ch A
bit3 - SOUND Chan#7 name=AY-3-8910 #2 Ch B
bit3 - SOUND Chan#8 name=AY-3-8910 #2 Ch C
*/
if (gain_control == (data & 0x0f))
return;
gain_control = data & 0x0f;
/*popmessage("gain_ctrl = %2x",data&0x0f);*/
percent = (gain_control & 1) ? 1.0 : 0.50;
sndti_set_output_gain(SOUND_AY8910, 0, 0, percent);
//fixme: set_RC_filter(0,10000,100000000,0,10000); /* 10K, 10000pF = 0.010uF */
percent = (gain_control & 2) ? 0.45 : 0.23;
sndti_set_output_gain(SOUND_AY8910, 0, 1, percent);
sndti_set_output_gain(SOUND_AY8910, 0, 2, percent);
sndti_set_output_gain(SOUND_AY8910, 1, 0, percent);
sndti_set_output_gain(SOUND_AY8910, 1, 1, percent);
//fixme: set_RC_filter(1,4700,100000000,0,4700); /* 4.7K, 4700pF = 0.0047uF */
//fixme: set_RC_filter(2,4700,100000000,0,4700); /* 4.7K, 4700pF = 0.0047uF */
//fixme: set_RC_filter(3,4700,100000000,0,4700); /* 4.7K, 4700pF = 0.0047uF */
//fixme: set_RC_filter(4,4700,100000000,0,4700); /* 4.7K, 4700pF = 0.0047uF */
percent = (gain_control & 4) ? 0.45 : 0.23;
sndti_set_output_gain(SOUND_AY8910, 1, 2, percent);
sndti_set_output_gain(SOUND_AY8910, 2, 0, percent);
percent = (gain_control & 8) ? 0.45 : 0.23;
sndti_set_output_gain(SOUND_AY8910, 2, 1, percent);
sndti_set_output_gain(SOUND_AY8910, 2, 2, percent);
}
