stfight.cpp: Remove YM2203 frequency hack, and set prescaler at machi…

…ne_start (#7992)

src/mame/drivers/stfight.cpp

@@ -245,11 +245,10 @@ conventional RAM. See the memory map for sprite data format.
 TODO:
 - handle transparency in text layer properly (how?)
 - second bank of sf02 is this used? (probably NOT)
-- stfight/empcity YM2203s should be clocked at 1.5MHz but this results in
-  the sound and music being 1/3 of the pitch they should be. The game never
-  writes the YM2203s' divider registers yet other games (e.g. Lock-On)
-  suggest the default values are correct.
-  cshootert however, sounds too high-pitched at 1.5MHz*3.
+- empcity/stfight never writes the YM2203s' divider registers but it expects
+  0x2f, there's a workaround for it in machine_start
+- empcity/stfight has an NMI handler, but it's not hooked up in MAME, missing
+  comms somewhere?
 - Each version of empcity/stfight has a different protection code stored in the
   MCU (at $1D2) so each 68705 will need to be dumped.
   We currently use hacked versions of the empcityu MCU for each different set.
@@ -483,14 +482,13 @@ void stfight_state::stfight_base(machine_config &config)
 	/* sound hardware */
 	SPEAKER(config, "mono").front_center();
 
-	// YM2203_PITCH_HACK - These should be clocked at 1.5Mhz (see TODO list)
-	ym2203_device &ym1(YM2203(config, "ym1", 12_MHz_XTAL / 8 * 3));
+	ym2203_device &ym1(YM2203(config, m_ym1, 12_MHz_XTAL / 8));
 	ym1.add_route(0, "mono", 0.15);
 	ym1.add_route(1, "mono", 0.15);
 	ym1.add_route(2, "mono", 0.15);
 	ym1.add_route(3, "mono", 0.10);
 
-	ym2203_device &ym2(YM2203(config, "ym2", 12_MHz_XTAL / 8 * 3));
+	ym2203_device &ym2(YM2203(config, m_ym2, 12_MHz_XTAL / 8));
 	ym2.add_route(0, "mono", 0.15);
 	ym2.add_route(1, "mono", 0.15);
 	ym2.add_route(2, "mono", 0.15);

src/mame/includes/stfight.h

@@ -6,6 +6,7 @@
 #pragma once
 
 #include "cpu/m6805/m68705.h"
+#include "sound/ym2203.h"
 #include "sound/msm5205.h"
 #include "video/stfight_dev.h"
 #include "video/airraid_dev.h"
@@ -20,6 +21,8 @@ class stfight_state : public driver_device
 		, m_audiocpu(*this, "audiocpu")
 		, m_mcu(*this, "mcu")
 		, m_msm(*this, "msm")
+		, m_ym1(*this, "ym1")
+		, m_ym2(*this, "ym2")
 		, m_main_bank(*this, "mainbank")
 		, m_samples(*this, "adpcm")
 		, m_decrypted_opcodes(*this, "decrypted_opcodes")
@@ -88,6 +91,9 @@ class stfight_state : public driver_device
 	required_device<m68705p5_device> m_mcu;
 	required_device<msm5205_device>  m_msm;
 
+	required_device<ym2203_device>   m_ym1;
+	required_device<ym2203_device>   m_ym2;
+
 	required_memory_bank             m_main_bank;
 
 	required_region_ptr<uint8_t>     m_samples;

src/mame/machine/stfight.cpp

@@ -80,6 +80,10 @@ void stfight_state::machine_start()
 
 	m_int1_timer = timer_alloc(TIMER_STFIGHT_INTERRUPT_1);
 
+	// Set clock prescaler FM:1/2 PSG:1/1
+	m_ym1->write(0, 0x2f); 
+	m_ym2->write(0, 0x2f);
+
 	save_item(NAME(m_coin_state));
 
 	save_item(NAME(m_fm_data));