tv955kb: Add bell and reset output

src/mame/drivers/tv955.cpp

@@ -104,7 +104,13 @@ void tv955_state::control_latch_w(u8 data)
 
 WRITE_LINE_MEMBER(tv955_state::system_reset_w)
 {
-	// TODO
+	m_maincpu->set_input_line(INPUT_LINE_RESET, state ? CLEAR_LINE : ASSERT_LINE);
+	if (!state)
+	{
+		m_keybuart->reset();
+		m_printuart->reset();
+		m_hostuart->reset();
+	}
 }
 
 void tv955_state::mem_map(address_map &map)
@@ -213,4 +219,4 @@ ROM_START( tv955 )
 	ROM_LOAD( "t180002-26b.u45",     0x0000, 0x1000, CRC(69c9ebc7) SHA1(32282c816ec597a7c45e939acb7a4155d35ea584) )
 ROM_END
 
-COMP( 1985, tv955, 0, 0, tv955, tv955, tv955_state, empty_init, "TeleVideo Systems", "TeleVideo 955", MACHINE_IS_SKELETON )
+COMP( 1985, tv955, 0, 0, tv955, tv955, tv955_state, empty_init, "TeleVideo Systems", "TeleVideo 955", MACHINE_NOT_WORKING | MACHINE_IMPERFECT_GRAPHICS )

src/mame/machine/tv955kb.cpp

@@ -17,6 +17,7 @@ Connector pinout:
 #include "emu.h"
 #include "machine/tv955kb.h"
 #include "machine/input_merger.h"
+#include "speaker.h"
 
 DEFINE_DEVICE_TYPE(TV955_KEYBOARD, tv955kb_device, "tv955kb", "TeleVideo 955 Keyboard")
 
@@ -25,7 +26,9 @@ tv955kb_device::tv955kb_device(const machine_config &mconfig, const char *tag, d
 	, m_txd_cb(*this)
 	, m_reset_cb(*this)
 	, m_mcu(*this, "mcu")
+	, m_bell(*this, "bell")
 	, m_keys(*this, "Y%u", 0U)
+	, m_bell_on(false)
 {
 }
 
@@ -37,6 +40,27 @@ void tv955kb_device::device_resolve_objects()
 
 void tv955kb_device::device_start()
 {
+	m_bell_timer = machine().scheduler().timer_alloc(timer_expired_delegate(FUNC(tv955kb_device::bell_q8), this));
+
+	save_item(NAME(m_bell_on));
+}
+
+void tv955kb_device::device_reset()
+{
+	bell_reset();
+}
+
+TIMER_CALLBACK_MEMBER(tv955kb_device::bell_q8)
+{
+	m_bell_on = !m_bell_on;
+	m_bell->level_w(m_bell_on);
+}
+
+void tv955kb_device::bell_reset()
+{
+	m_bell_on = false;
+	m_bell->level_w(0);
+	m_bell_timer->enable(false);
 }
 
 WRITE_LINE_MEMBER(tv955kb_device::write_rxd)
@@ -59,7 +83,14 @@ u8 tv955kb_device::keys_r()
 
 WRITE_LINE_MEMBER(tv955kb_device::bell_w)
 {
-	// TODO
+	if (state && m_bell_timer->enabled())
+		bell_reset();
+	else if (!state && !m_bell_timer->enabled())
+	{
+		// Speaker driven through 2N4401 from Q8 output of MC14040 clocked by ALE
+		attotime period = m_mcu->cycles_to_attotime(128);
+		m_bell_timer->adjust(period, 0, period);
+	}
 }
 
 WRITE_LINE_MEMBER(tv955kb_device::txd_w)
@@ -69,6 +100,9 @@ WRITE_LINE_MEMBER(tv955kb_device::txd_w)
 
 WRITE_LINE_MEMBER(tv955kb_device::reset_w)
 {
+	m_mcu->set_input_line(INPUT_LINE_RESET, state ? CLEAR_LINE : ASSERT_LINE);
+	if (!state)
+		bell_reset();
 	m_reset_cb(state);
 }
 
@@ -82,9 +116,11 @@ void tv955kb_device::device_add_mconfig(machine_config &config)
 	m_mcu->t1_in_cb().set_ioport("FUNCT").bit(1);
 	m_mcu->bus_in_cb().set(FUNC(tv955kb_device::keys_r));
 
-	INPUT_MERGER_ALL_LOW(config, "resetctl").output_handler().set(FUNC(tv955kb_device::reset_w));
+	input_merger_device &resetctl(INPUT_MERGER_ALL_LOW(config, "resetctl"));
+	resetctl.output_handler().set(FUNC(tv955kb_device::reset_w)).invert();
 
-	// TODO: bell (MC14040 clocked by ALE)
+	SPEAKER(config, "mono").front_center();
+	SPEAKER_SOUND(config, m_bell).add_route(ALL_OUTPUTS, "mono", 0.05);
 }
 
 static INPUT_PORTS_START(tv955kb)

src/mame/machine/tv955kb.h

@@ -7,9 +7,7 @@
 #pragma once
 
 #include "cpu/mcs48/mcs48.h"
-//#include "machine/ripple_counter.h"
-//#include "sound/spkrdev.h"
-//#include "speaker.h"
+#include "sound/spkrdev.h"
 
 
 //**************************************************************************
@@ -29,12 +27,11 @@ public:
 
 	DECLARE_WRITE_LINE_MEMBER(write_rxd);
 
-	static constexpr feature_type unemulated_features() { return feature::SOUND; }
-
 protected:
 	// device-specific overrides
 	virtual void device_resolve_objects() override;
 	virtual void device_start() override;
+	virtual void device_reset() override;
 	virtual void device_add_mconfig(machine_config &config) override;
 	virtual ioport_constructor device_input_ports() const override;
 	virtual const tiny_rom_entry *device_rom_region() const override;
@@ -45,12 +42,19 @@ private:
 	DECLARE_WRITE_LINE_MEMBER(txd_w);
 	DECLARE_WRITE_LINE_MEMBER(reset_w);
 
+	TIMER_CALLBACK_MEMBER(bell_q8);
+	void bell_reset();
+
 	// line output callbacks
 	devcb_write_line m_txd_cb;
 	devcb_write_line m_reset_cb;
 
 	required_device<mcs48_cpu_device> m_mcu;
+	required_device<speaker_sound_device> m_bell;
 	required_ioport_array<16> m_keys;
+
+	emu_timer *m_bell_timer;
+	bool m_bell_on;
 };
 
 // device type definition