Add device emulation for MM5307 Baud Rate Generator

scripts/src/machine.lua

@@ -1974,6 +1974,18 @@ if (MACHINES["MICROTOUCH"]~=null) then
 	}
 end
 
+---------------------------------------------------
+--
+--@src/devices/machine/mm5307.h,MACHINES["MM5307"] = true
+---------------------------------------------------
+
+if (MACHINES["MM5307"]~=null) then
+	files {
+		MAME_DIR .. "src/devices/machine/mm5307.cpp",
+		MAME_DIR .. "src/devices/machine/mm5307.h",
+	}
+end
+
 ---------------------------------------------------
 --
 --@src/devices/machine/mm58274c.h,MACHINES["MM58274C"] = true

scripts/target/mame/arcade.lua

@@ -520,6 +520,7 @@ MACHINES["MCF5206E"] = true
 MACHINES["METERS"] = true
 MACHINES["MICROTOUCH"] = true
 --MACHINES["MIOT6530"] = true
+--MACHINES["MM5307"] = true
 --MACHINES["MM58167"] = true
 MACHINES["MM58274C"] = true
 MACHINES["MM74C922"] = true

scripts/target/mame/mess.lua

@@ -524,6 +524,7 @@ MACHINES["MCCS1850"] = true
 MACHINES["MCF5206E"] = true
 MACHINES["MICROTOUCH"] = true
 MACHINES["MIOT6530"] = true
+MACHINES["MM5307"] = true
 MACHINES["MM58167"] = true
 MACHINES["MM58274C"] = true
 MACHINES["MM74C922"] = true

src/devices/machine/mm5307.cpp

@@ -0,0 +1,222 @@
+// license:BSD-3-Clause
+// copyright-holders:AJR
+/***************************************************************************
+
+    National Semiconductor MM5307 Baud Rate Generator/Programmable Divider
+
+    The MM5307 divides the frequency of a crystal oscillator or external
+    clock (maximum 1 MHz, ideally 921.6 kHz) to generate a single baud
+    rate output. (The undivided frequency is also output on another pin,
+    not emulated here.)
+
+    The four control inputs (A, B, C, D) select one of 15 mask-programmed
+    divisors or an independent external frequency. When the selected
+    divisor is 2N, the output has a duty cycle of exactly 50%. When the
+    selected divisor is 2N + 1, the high output is always one clock cycle
+    longer than the low output. When the selected divisor is 2N + 0.5,
+    the duty cycle varies slightly from phase to phase.
+
+    The MM5307 resets its output frequency when the reset input is pulsed
+    low or the control inputs change.
+
+***************************************************************************/
+
+#include "emu.h"
+#include "mm5307.h"
+
+#define VERBOSE 0
+#include "logmacro.h"
+
+//**************************************************************************
+//  GLOBAL VARIABLES
+//**************************************************************************
+
+// device type definitions
+DEFINE_DEVICE_TYPE(MM5307AA, mm5307aa_device, "mm5307aa", "MM5307AA Baud Rate Generator")
+DEFINE_DEVICE_TYPE(MM5307AB, mm5307ab_device, "mm5307ab", "MM5307AB Baud Rate Generator")
+
+
+//**************************************************************************
+//  DIVISOR TABLES
+//**************************************************************************
+
+const std::array<u16, 16> mm5307aa_device::s_divisors_x2 = {
+	0,      // external frequency (not divided)
+	2304,   // 50 baud (divide by 1152)
+	1536,   // 75 baud (divide by 768)
+	1048,   // 110 baud (divide by 524)
+	857,    // 134.5 baud (divide by 428.5)
+	768,    // 150 baud (divide by 384)
+	384,    // 300 baud (divide by 192)
+	192,    // 600 baud (divide by 96)
+	128,    // 900 baud (divide by 64)
+	96,     // 1200 baud (divide by 48)
+	64,     // 1800 baud (divide by 32)
+	48,     // 2400 baud (divide by 24)
+	32,     // 3600 baud (divide by 16)
+	24,     // 4800 baud (divide by 12)
+	16,     // 7200 baud (divide by 8)
+	12      // 9600 baud (divide by 6)
+};
+
+
+const std::array<u16, 16> mm5307ab_device::s_divisors_x2 = {
+	0,      // external frequency (not divided)
+	2304,   // 50 baud (divide by 1152)
+	576,    // 200 baud (divide by 288)
+	1048,   // 110 baud (divide by 524)
+	857,    // 134.5 baud (divide by 428.5)
+	768,    // 150 baud (divide by 384)
+	384,    // 300 baud (divide by 192)
+	192,    // 600 baud (divide by 96)
+	128,    // 900 baud (divide by 64)
+	96,     // 1200 baud (divide by 48)
+	64,     // 1800 baud (divide by 32)
+	48,     // 2400 baud (divide by 24)
+	32,     // 3600 baud (divide by 16)
+	24,     // 4800 baud (divide by 12)
+	1536,   // 75 baud (divide by 768)
+	12      // 9600 baud (divide by 6)
+};
+
+
+//**************************************************************************
+//  DEVICE IMPLEMENTATION
+//**************************************************************************
+
+//-------------------------------------------------
+//  mm5307_device - constructor
+//-------------------------------------------------
+
+mm5307_device::mm5307_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock, const std::array<u16, 16> &divisors_x2)
+	: device_t(mconfig, type, tag, owner, clock)
+	, m_divisors_x2(divisors_x2)
+	, m_output_cb(*this)
+	, m_ext_freq(0)
+	, m_freq_control(0)
+	, m_phase(0)
+	, m_periodic_timer(nullptr)
+{
+}
+
+
+//-------------------------------------------------
+//  mm5307aa_device - constructor
+//-------------------------------------------------
+
+mm5307aa_device::mm5307aa_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
+	: mm5307_device(mconfig, MM5307AA, tag, owner, clock, s_divisors_x2)
+{
+}
+
+
+//-------------------------------------------------
+//  mm5307ab_device - constructor
+//-------------------------------------------------
+
+mm5307ab_device::mm5307ab_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
+	: mm5307_device(mconfig, MM5307AB, tag, owner, clock, s_divisors_x2)
+{
+}
+
+
+//-------------------------------------------------
+//  device_resolve_objects - resolve objects that
+//  may be needed for other devices to set
+//  initial conditions at start time
+//-------------------------------------------------
+
+void mm5307_device::device_resolve_objects()
+{
+	// Resolve callback
+	m_output_cb.resolve_safe();
+}
+
+
+//-------------------------------------------------
+//  device_start - device-specific startup
+//-------------------------------------------------
+
+void mm5307_device::device_start()
+{
+	// Create timer
+	m_periodic_timer = machine().scheduler().timer_alloc(timer_expired_delegate(FUNC(mm5307_device::periodic_update), this));
+
+	// Register for saving
+	save_item(NAME(m_freq_control));
+	save_item(NAME(m_phase));
+}
+
+
+//-------------------------------------------------
+//  device_reset - device-specific reset
+//-------------------------------------------------
+
+void mm5307_device::device_reset()
+{
+	// Output delay from reset
+	m_periodic_timer->adjust(attotime::from_usec(500) + clocks_to_attotime(4));
+}
+
+
+//-------------------------------------------------
+//  control_w - set frequency control
+//-------------------------------------------------
+
+void mm5307_device::control_w(u8 data)
+{
+	data &= 15;
+	if (data != m_freq_control)
+	{
+		m_freq_control = data;
+
+		if (m_divisors_x2[data] == 0)
+			LOG("%s: External frequency selected\n", machine().describe_context());
+		else
+			LOG("%s: %.1f baud selected\n", machine().describe_context(), clock() / (8.0 * m_divisors_x2[data]));
+
+		// Emulate access time
+		m_periodic_timer->adjust(attotime::from_usec(2800) + clocks_to_attotime(13));
+	}
+}
+
+
+//-------------------------------------------------
+//  periodic_update - update output state and
+//  reset timer for next period
+//-------------------------------------------------
+
+TIMER_CALLBACK_MEMBER(mm5307_device::periodic_update)
+{
+	// Up to four different phases
+	m_phase = (m_phase + 1) & 3;
+	m_output_cb(BIT(m_phase, 0));
+
+	u16 divisor = m_divisors_x2[m_freq_control];
+	if (divisor == 0)
+	{
+		m_periodic_timer->adjust(m_ext_freq == 0 ? attotime::never : attotime::from_hz(m_ext_freq) / 2);
+	}
+	else switch (m_phase)
+	{
+	// First low output phase
+	case 0:
+		m_periodic_timer->adjust(clocks_to_attotime(divisor & ~2) / 2);
+		break;
+
+	// First high output phase
+	case 1:
+		m_periodic_timer->adjust(clocks_to_attotime(divisor >> 1));
+		break;
+
+	// Second low output phase
+	case 2:
+		m_periodic_timer->adjust(clocks_to_attotime((divisor & ~2) >> 1 | (divisor & 1)));
+		break;
+
+	// Second high output phase
+	case 3:
+		m_periodic_timer->adjust(clocks_to_attotime(divisor - ((divisor & 1) << 1)) / 2);
+		break;
+	}
+}

src/devices/machine/mm5307.h

@@ -0,0 +1,99 @@
+// license:BSD-3-Clause
+// copyright-holders:AJR
+/***************************************************************************
+
+    National Semiconductor MM5307 Baud Rate Generator/Programmable Divider
+
+****************************************************************************
+                                 ___    ___
+              EXTERNAL FREQ   1 |*  \__/   | 14  ϕOUT
+                         NC   2 |          | 13  RESET
+                     OUTPUT   3 |          | 12  Vgg
+                        Vss   4 |  MM5307  | 11  A
+             EXTERNAL CLOCK   5 |          | 10  B
+                    CRYSTAL   6 |          |  9  C
+                    CRYSTAL   7 |__________|  8  D
+
+***************************************************************************/
+
+#ifndef MAME_MACHINE_MM5307_H
+#define MAME_MACHINE_MM5307_H 1
+
+#pragma once
+
+//**************************************************************************
+//  TYPE DEFINITIONS
+//**************************************************************************
+
+// ======================> mm5307_device
+
+class mm5307_device : public device_t
+{
+public:
+	// configuration
+	void set_ext_freq(u32 freq) { m_ext_freq = freq; }
+	void set_ext_freq(const XTAL &freq) { m_ext_freq = freq.value(); }
+	auto output_cb() { return m_output_cb.bind(); }
+
+	// frequency control
+	void control_w(u8 data);
+
+protected:
+	// base class constructor
+	mm5307_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock, const std::array<u16, 16> &divisors_x2);
+
+	// device-specific overrides
+	virtual void device_resolve_objects() override;
+	virtual void device_start() override;
+	virtual void device_reset() override;
+
+private:
+	// timed update callback
+	TIMER_CALLBACK_MEMBER(periodic_update);
+
+	// internal divisors
+	const std::array<u16, 16> &m_divisors_x2;
+
+	// callbacks
+	devcb_write_line m_output_cb;
+
+	// external input frequency
+	u32 m_ext_freq;
+
+	// internal state
+	u8 m_freq_control;
+	u8 m_phase;
+
+	// timer
+	emu_timer *m_periodic_timer;
+};
+
+// ======================> mm5307aa_device
+
+class mm5307aa_device : public mm5307_device
+{
+public:
+	// construction/destruction
+	mm5307aa_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock);
+
+private:
+	static const std::array<u16, 16> s_divisors_x2;
+};
+
+// ======================> mm5307ab_device
+
+class mm5307ab_device : public mm5307_device
+{
+public:
+	// construction/destruction
+	mm5307ab_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock);
+
+private:
+	static const std::array<u16, 16> s_divisors_x2;
+};
+
+// device type declarations
+DECLARE_DEVICE_TYPE(MM5307AA, mm5307aa_device)
+DECLARE_DEVICE_TYPE(MM5307AB, mm5307ab_device)
+
+#endif // MAME_MACHINE_MM5307_H

src/mame/drivers/poly88.cpp

@@ -69,7 +69,7 @@ void poly88_state::poly88_io(address_map &map)
 {
 	map.unmap_value_high();
 	map.global_mask(0xff);
-	map(0x00, 0x01).rw(m_uart, FUNC(i8251_device::read), FUNC(i8251_device::write));
+	map(0x00, 0x01).rw(m_usart, FUNC(i8251_device::read), FUNC(i8251_device::write));
 	map(0x04, 0x04).w(FUNC(poly88_state::poly88_baud_rate_w));
 	map(0x08, 0x08).w(FUNC(poly88_state::poly88_intr_w));
 	map(0xf8, 0xf8).r(FUNC(poly88_state::poly88_keyboard_r));
@@ -201,7 +201,7 @@ GFXDECODE_END
 
 MACHINE_CONFIG_START(poly88_state::poly88)
 	/* basic machine hardware */
-	I8080A(config, m_maincpu, XTAL(16'588'800) / 9); // uses 8224 clock generator
+	I8080A(config, m_maincpu, 16.5888_MHz_XTAL / 9); // uses 8224 clock generator
 	m_maincpu->set_addrmap(AS_PROGRAM, &poly88_state::poly88_mem);
 	m_maincpu->set_addrmap(AS_IO, &poly88_state::poly88_io);
 	m_maincpu->set_vblank_int("screen", FUNC(poly88_state::poly88_interrupt));
@@ -230,9 +230,12 @@ MACHINE_CONFIG_START(poly88_state::poly88)
 	m_cassette->set_default_state(CASSETTE_STOPPED | CASSETTE_SPEAKER_ENABLED);
 
 	/* uart */
-	I8251(config, m_uart, XTAL(16'588'800) / 9);
+	I8251(config, m_usart, 16.5888_MHz_XTAL / 9);
-	m_uart->txd_handler().set(FUNC(poly88_state::write_cas_tx));
+	m_usart->txd_handler().set(FUNC(poly88_state::write_cas_tx));
-	m_uart->rxrdy_handler().set(FUNC(poly88_state::poly88_usart_rxready));
+	m_usart->rxrdy_handler().set(FUNC(poly88_state::poly88_usart_rxready));
+
+	MM5307AA(config, m_brg, 16.5888_MHz_XTAL / 18);
+	m_brg->output_cb().set(FUNC(poly88_state::cassette_txc_rxc_w));
 
 	/* snapshot */
 	MCFG_SNAPSHOT_ADD("snapshot", poly88_state, poly88, "img", attotime::from_seconds(2))

src/mame/includes/poly88.h

@@ -11,6 +11,7 @@
 #pragma once
 
 #include "machine/i8251.h"
+#include "machine/mm5307.h"
 #include "imagedev/cassette.h"
 #include "imagedev/snapquik.h"
 
@@ -20,15 +21,15 @@ public:
 	enum
 	{
 		TIMER_USART,
-		TIMER_KEYBOARD,
+		TIMER_KEYBOARD
-		TIMER_CASSETTE
 	};
 
 	poly88_state(const machine_config &mconfig, device_type type, const char *tag) :
 		driver_device(mconfig, type, tag),
 		m_video_ram(*this, "video_ram"),
 		m_maincpu(*this, "maincpu"),
-		m_uart(*this, "uart"),
+		m_usart(*this, "usart"),
+		m_brg(*this, "brg"),
 		m_cassette(*this, "cassette"),
 		m_linec(*this, "LINEC"),
 		m_line0(*this, "LINE0"),
@@ -51,8 +52,8 @@ private:
 	uint8_t m_intr;
 	uint8_t m_last_code;
 	uint8_t m_int_vector;
-	emu_timer * m_cassette_timer;
 	emu_timer * m_usart_timer;
+	emu_timer * m_keyboard_timer;
 	int m_previous_level;
 	int m_clk_level;
 	int m_clk_level_tape;
@@ -65,7 +66,7 @@ private:
 	INTERRUPT_GEN_MEMBER(poly88_interrupt);
 	TIMER_CALLBACK_MEMBER(poly88_usart_timer_callback);
 	TIMER_CALLBACK_MEMBER(keyboard_callback);
-	TIMER_CALLBACK_MEMBER(poly88_cassette_timer_callback);
+	DECLARE_WRITE_LINE_MEMBER(cassette_txc_rxc_w);
 	DECLARE_WRITE_LINE_MEMBER(write_cas_tx);
 	DECLARE_WRITE_LINE_MEMBER(poly88_usart_rxready);
 	IRQ_CALLBACK_MEMBER(poly88_irq_callback);
@@ -77,7 +78,8 @@ private:
 	void poly88_mem(address_map &map);
 
 	required_device<cpu_device> m_maincpu;
-	required_device<i8251_device> m_uart;
+	required_device<i8251_device> m_usart;
+	required_device<mm5307_device> m_brg;
 	required_device<cassette_image_device> m_cassette;
 	required_ioport m_linec;
 	required_ioport m_line0;

src/mame/machine/poly88.cpp

@@ -24,9 +24,6 @@ void poly88_state::device_timer(emu_timer &timer, device_timer_id id, int param,
 	case TIMER_KEYBOARD:
 		keyboard_callback(ptr, param);
 		break;
-	case TIMER_CASSETTE:
-		poly88_cassette_timer_callback(ptr, param);
-		break;
 	default:
 		assert_always(false, "Unknown id in poly88_state::device_timer");
 	}
@@ -42,9 +39,10 @@ TIMER_CALLBACK_MEMBER(poly88_state::poly88_usart_timer_callback)
 WRITE8_MEMBER(poly88_state::poly88_baud_rate_w)
 {
 	logerror("poly88_baud_rate_w %02x\n",data);
-	m_usart_timer = timer_alloc(TIMER_USART);
+	m_brg->control_w(data & 15);
-	m_usart_timer->adjust(attotime::zero, 0, attotime::from_hz(300));
 
+	// FIXME
+	m_usart_timer->adjust(attotime::zero, 0, attotime::from_hz(300));
 }
 
 uint8_t poly88_state::row_number(uint8_t code) {
@@ -149,8 +147,6 @@ TIMER_CALLBACK_MEMBER(poly88_state::keyboard_callback)
 	} else {
 		m_last_code = key_code;
 	}
-
-	timer_set(attotime::from_hz(24000), TIMER_KEYBOARD);
 }
 
 IRQ_CALLBACK_MEMBER(poly88_state::poly88_irq_callback)
@@ -163,7 +159,7 @@ WRITE_LINE_MEMBER(poly88_state::write_cas_tx)
 	m_cas_tx = state;
 }
 
-TIMER_CALLBACK_MEMBER(poly88_state::poly88_cassette_timer_callback)
+WRITE_LINE_MEMBER(poly88_state::cassette_txc_rxc_w)
 {
 	int data;
 	int current_level;
@@ -186,13 +182,13 @@ TIMER_CALLBACK_MEMBER(poly88_state::poly88_cassette_timer_callback)
 				{
 					data = (!m_previous_level && current_level) ? 1 : 0;
 //data = current_level;
-					m_uart->write_rxd(data);
+					m_usart->write_rxd(data);
 
 					m_clk_level_tape = 1;
 				}
 			}
 
-			m_uart->write_rxc(m_clk_level_tape);
+			m_usart->write_rxc(m_clk_level_tape);
 		}
 
 		/* tape writing */
@@ -203,15 +199,14 @@ TIMER_CALLBACK_MEMBER(poly88_state::poly88_cassette_timer_callback)
 			m_cassette->output(data&0x01 ? 1 : -1);
 
 			m_clk_level_tape = m_clk_level_tape ? 0 : 1;
-			m_uart->write_txc(m_clk_level_tape);
+			m_usart->write_txc(m_clk_level_tape);
 
 			return;
 		}
 
 		m_clk_level_tape = 1;
 
-		m_clk_level = m_clk_level ? 0 : 1;
+		m_usart->write_txc(state);
-		m_uart->write_txc(m_clk_level);
 //  }
 }
 
@@ -219,17 +214,19 @@ TIMER_CALLBACK_MEMBER(poly88_state::poly88_cassette_timer_callback)
 void poly88_state::init_poly88()
 {
 	m_previous_level = 0;
-	m_clk_level = m_clk_level_tape = 1;
+	m_clk_level_tape = 1;
-	m_cassette_timer = timer_alloc(TIMER_CASSETTE);
-	m_cassette_timer->adjust(attotime::zero, 0, attotime::from_hz(600));
 
-	timer_set(attotime::from_hz(24000), TIMER_KEYBOARD);
+	m_usart_timer = timer_alloc(TIMER_USART);
+	m_keyboard_timer = timer_alloc(TIMER_KEYBOARD);
+	m_keyboard_timer->adjust(attotime::from_hz(24000), 0, attotime::from_hz(24000));
 }
 
 void poly88_state::machine_reset()
 {
 	m_intr = 0;
 	m_last_code = 0;
+
+	m_brg->control_w(0);
 }
 
 INTERRUPT_GEN_MEMBER(poly88_state::poly88_interrupt)
@@ -327,6 +324,6 @@ SNAPSHOT_LOAD_MEMBER( poly88_state, poly88 )
 		}
 		pos+=recordLen;
 	}
-	m_uart->reset();
+	m_usart->reset();
 	return image_init_result::PASS;
 }