Option to disable VMU sounds. VMU sounds use better waveform.

core/cfg/option.cpp

@@ -60,6 +60,7 @@ Option<bool> AutoLatency("aica.AutoLatency",
 
 OptionString AudioBackend("backend", "auto", "audio");
 AudioVolumeOption AudioVolume;
+Option<bool> VmuSound("VmuSound", false, "audio");
 
 // Rendering
 

core/cfg/option.h

@@ -409,6 +409,7 @@ public:
 	}
 };
 extern AudioVolumeOption AudioVolume;
+extern Option<bool> VmuSound;
 
 // Rendering
 

core/hw/aica/sgc_if.cpp

@@ -169,6 +169,7 @@ const DSP_OUT_VOL_REG *dsp_out_vol = (DSP_OUT_VOL_REG *)&aica_reg[0x2000];
 static int beepOn;
 static int beepPeriod;
 static int beepCounter;
+static SampleType beepValue;
 
 #pragma pack(push, 1)
 //All regs are 16b , aligned to 32b (upper bits 0?)
@@ -786,13 +787,14 @@ struct ChannelEx
 	
 	void RegWrite(u32 offset, int size)
 	{
-		switch(offset)
+		switch (offset)
 		{
 		case 0x00:
 		case 0x01:
 			UpdateStreamStep();
-			UpdateSA();
-			if ((offset == 0x01 || size == 2) && ccd->KYONEX)
+			if (offset == 0 || size == 2)
+				UpdateSA();
+			if ((offset == 1 || size == 2) && ccd->KYONEX)
 			{
 				ccd->KYONEX=0;
 				for (ChannelEx& channel : Chans)
@@ -1322,6 +1324,7 @@ void sgc_Init()
 	beepOn = 0;
 	beepPeriod = 0;
 	beepCounter = 0;
+	beepValue = 0;
 
 	dsp::init();
 }
@@ -1401,8 +1404,8 @@ void vmuBeep(int on, int period)
 	{
 		// The maple doc may be wrong on this. It looks like the raw values of T1LR and T1LC are set.
 		// So the period is (256 - T1LR) / (32768 / 6)
-		// and the duty cycle is (T1LC - T1LR) / (32768 / 6)
-		beepOn = (on - period) * 8;
+		// and the duty cycle is (256 - T1LC) / (32768 / 6)
+		beepOn = (256 - on) * 8;
 		beepPeriod = (256 - period) * 8;
 		beepCounter = 0;
 	}
@@ -1410,16 +1413,24 @@ void vmuBeep(int on, int period)
 
 static SampleType vmuBeepSample()
 {
+	constexpr int Slope = 500;
 	if (beepPeriod == 0)
-		return 0;
-	SampleType s;
-	if (beepCounter <= beepOn)
-		s = 16383;
+	{
+		if (beepValue > 0)
+			beepValue = std::max(0, beepValue - Slope);
+		else if (beepValue < 0)
+			beepValue = std::min(0, beepValue + Slope);
+	}
 	else
-		s = -16384;
-	beepCounter = (beepCounter + 1) % beepPeriod;
+	{
+		if (beepCounter <= beepOn)
+			beepValue = std::min(16383, beepValue + Slope);
+		else
+			beepValue = std::max(-16384, beepValue - Slope);
+		beepCounter = (beepCounter + 1) % beepPeriod;
+	}
 
-	return s;
+	return beepValue;
 }
 
 constexpr int CDDA_SIZE = 2352 / 2;
@@ -1468,9 +1479,12 @@ void AICA_Sample()
 	if (settings.input.fastForwardMode || settings.aica.muteAudio)
 		return;
 
-	SampleType beep = vmuBeepSample();
-	mixl += beep;
-	mixr += beep;
+	if (config::VmuSound)
+	{
+		SampleType beep = vmuBeepSample();
+		mixl += beep;
+		mixr += beep;
+	}
 
 	//Mono !
 	if (CommonData->Mono)

core/hw/maple/maple_devs.cpp

@@ -680,11 +680,11 @@ struct maple_sega_vmu: maple_base
 				{
 				case MFID_3_Clock:
 					{
-						u8 on = r8();
-						u8 period = r8();
+						u8 alw = r8();
+						u8 ald = r8();
 						r16(); // Alarm 2
-						INFO_LOG(MAPLE, "BEEP: %d/%d", on, period);
-						vmuBeep(on, period);
+						INFO_LOG(MAPLE, "BEEP: %d/%d", alw, ald);
+						vmuBeep(alw, ald);
 					}
 					return MDRS_DeviceReply;
 

core/rend/gui.cpp

@@ -2042,6 +2042,8 @@ static void gui_display_settings()
 			ImGui::PushStyleVar(ImGuiStyleVar_FramePadding, normal_padding);
 			OptionCheckbox("Enable DSP", config::DSPEnabled,
 					"Enable the Dreamcast Digital Sound Processor. Only recommended on fast platforms");
+            OptionCheckbox("Enable VMU Sounds", config::VmuSound, "Play VMU beeps when enabled.");
+
 			if (OptionSlider("Volume Level", config::AudioVolume, 0, 100, "Adjust the emulator's audio level"))
 			{
 				config::AudioVolume.calcDbPower();

shell/libretro/libretro_core_options.h

@@ -865,6 +865,19 @@ struct retro_core_option_v2_definition option_defs_us[] = {
       },
       "disabled",
    },
+   {
+      CORE_OPTION_NAME "_vmu_sound",
+      "Visual Memory Units/Systems (VMU) Sounds",
+      "VMU Sounds",
+      "When enabled, VMU beeps are played.",
+      NULL,
+      "vmu",
+      {
+         { "disabled", NULL },
+         { "enabled",   NULL },
+      },
+      "disabled",
+   },
    {
       CORE_OPTION_NAME "_show_vmu_screen_settings",
       "Show Visual Memory Unit/System (VMU) Display Settings",

shell/libretro/option.cpp

@@ -50,6 +50,7 @@ Option<int> AudioBufferSize("", 2822);	// 64 ms
 Option<bool> AutoLatency("");
 
 OptionString AudioBackend("", "auto");
+Option<bool> VmuSound(CORE_OPTION_NAME "_vmu_sound", false);
 
 // Rendering