mc68000: Add floppy support

scripts/src/bus.lua

@@ -5250,6 +5250,8 @@ if (BUSES["MC68000_SYSBUS"]~=null) then
 		MAME_DIR .. "src/devices/bus/mc68000/sysbus.h",
 		MAME_DIR .. "src/devices/bus/mc68000/cards.cpp",
 		MAME_DIR .. "src/devices/bus/mc68000/cards.h",
+		MAME_DIR .. "src/devices/bus/mc68000/floppy.cpp",
+		MAME_DIR .. "src/devices/bus/mc68000/floppy.h",
 		MAME_DIR .. "src/devices/bus/mc68000/ram.cpp",
 		MAME_DIR .. "src/devices/bus/mc68000/ram.h",
 	}

src/devices/bus/mc68000/cards.cpp

@@ -9,9 +9,11 @@
 #include "emu.h"
 #include "cards.h"
 
+#include "floppy.h"
 #include "ram.h"
 
 void mc68000_sysbus_cards(device_slot_interface &device)
 {
+	device.option_add("floppy", MC68000_FLOPPY);
 	device.option_add("ram", MC68000_RAM);
 }

src/devices/bus/mc68000/floppy.cpp

@@ -0,0 +1,169 @@
+// license: BSD-3-Clause
+// copyright-holders: Dirk Best
+/***************************************************************************
+
+    mc-68000-Computer Floppy Interface Card
+
+    TODO:
+    - Jumpers can change the meaning of some lines
+
+    Notes:
+    - Has two bus interfaces and supports up to 8 drives
+    - Can either use the 1793 or 1797
+
+***************************************************************************/
+
+#include "emu.h"
+#include "floppy.h"
+
+#define VERBOSE 0
+
+DEFINE_DEVICE_TYPE(MC68000_FLOPPY, mc68000_floppy_device, "mc68000_floppy", "mc-68000 Floppy Interface")
+
+mc68000_floppy_device::mc68000_floppy_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
+	device_t(mconfig, MC68000_FLOPPY, tag, owner, clock),
+	device_mc68000_sysbus_card_interface(mconfig, *this),
+	m_fdc(*this, "fdc"),
+	m_floppy(*this, "fdc:%u", 0U),
+	m_latch(0x00)
+{
+}
+
+// very flexible regarding drive support, we just add the most common ones
+static void mc68000_bus1_floppies(device_slot_interface &device)
+{
+	device.option_add("35dd", FLOPPY_35_DD);
+	device.option_add("525qd", FLOPPY_525_QD);
+}
+
+static void mc68000_bus2_floppies(device_slot_interface &device)
+{
+	device.option_add("8dsdd", FLOPPY_8_DSDD);
+}
+
+void mc68000_floppy_device::device_add_mconfig(machine_config &config)
+{
+	FD1793(config, m_fdc, 16_MHz_XTAL / 8);
+	m_fdc->intrq_wr_callback().set(FUNC(mc68000_floppy_device::intrq_w));
+	m_fdc->drq_wr_callback().set(FUNC(mc68000_floppy_device::drq_w));
+
+	// floppy drive bus 1
+	FLOPPY_CONNECTOR(config, m_floppy[0], mc68000_bus1_floppies, "525qd", floppy_image_device::default_mfm_floppy_formats);
+	FLOPPY_CONNECTOR(config, m_floppy[1], mc68000_bus1_floppies, "525qd", floppy_image_device::default_mfm_floppy_formats);
+	FLOPPY_CONNECTOR(config, m_floppy[2], mc68000_bus1_floppies, nullptr, floppy_image_device::default_mfm_floppy_formats);
+	FLOPPY_CONNECTOR(config, m_floppy[3], mc68000_bus1_floppies, nullptr, floppy_image_device::default_mfm_floppy_formats);
+
+	// floppy drive bus 2
+	FLOPPY_CONNECTOR(config, m_floppy[4], mc68000_bus2_floppies, nullptr, floppy_image_device::default_mfm_floppy_formats);
+	FLOPPY_CONNECTOR(config, m_floppy[5], mc68000_bus2_floppies, nullptr, floppy_image_device::default_mfm_floppy_formats);
+	FLOPPY_CONNECTOR(config, m_floppy[6], mc68000_bus2_floppies, nullptr, floppy_image_device::default_mfm_floppy_formats);
+	FLOPPY_CONNECTOR(config, m_floppy[7], mc68000_bus2_floppies, nullptr, floppy_image_device::default_mfm_floppy_formats);
+}
+
+void mc68000_floppy_device::device_start()
+{
+	// register for save states
+	save_item(NAME(m_latch));
+}
+
+void mc68000_floppy_device::device_reset()
+{
+	m_latch = 0x00;
+}
+
+uint16_t mc68000_floppy_device::floppy_r(offs_t offset, uint16_t mem_mask)
+{
+	uint16_t data = 0xffff;
+
+	if (ACCESSING_BITS_8_15)
+	{
+		switch (offset & 0x07)
+		{
+		case 0:
+		case 1:
+		case 2:
+		case 3:
+			data &= (m_fdc->read(offset & 0x03) << 8) | 0xff;
+			break;
+
+		case 4:
+			// 7-------  intrq from fdc
+			// -6------  drq from fdc
+			// --543210  write only
+
+			data &= (m_latch << 8) | 0xff;
+		}
+	}
+
+	return data & mem_mask;
+}
+
+void mc68000_floppy_device::floppy_w(offs_t offset, uint16_t data, uint16_t mem_mask)
+{
+	if (VERBOSE)
+		logerror("floppy_w: %06x = %04x & %04x\n", offset, data, mem_mask);
+
+	if (ACCESSING_BITS_8_15)
+	{
+		data >>= 8;
+
+		switch (offset & 0x07)
+		{
+		case 0:
+		case 1:
+		case 2:
+		case 3:
+			m_fdc->write(offset & 0x03, data);
+			break;
+
+		case 4:
+			// 76------  read only
+			// --5-----  side select
+			// ---4----  force ready
+			// ----3---  density select
+			// -----2--  bus select
+			// ------10  drive select
+
+			floppy_image_device *floppy = nullptr;
+
+			if (BIT(data, 2))
+			{
+				// bus 1, drives 0 to 3 at 1 MHz
+				floppy = m_floppy[0 + (data & 0x03)]->get_device();
+				m_fdc->set_clock_scale(0.5);
+			}
+			else
+			{
+				// bus 2, drives 4 to 7 at 2 MHz
+				floppy = m_floppy[4 + (data & 0x03)]->get_device();
+				m_fdc->set_clock_scale(1.0);
+			}
+
+			m_fdc->set_floppy(floppy);
+
+			if (floppy)
+			{
+				// TODO: motor should only run for a few seconds after each access (for bus 1)
+				floppy->mon_w(0);
+				floppy->ss_w(BIT(data, 5));
+			}
+
+			m_fdc->dden_w(BIT(data, 3));
+			m_fdc->set_force_ready(BIT(data, 4));
+		}
+	}
+}
+
+void mc68000_floppy_device::intrq_w(int state)
+{
+	m_latch &= ~(1 << 7);
+	m_latch |= state << 7;
+}
+
+void mc68000_floppy_device::drq_w(int state)
+{
+	m_latch &= ~(1 << 6);
+	m_latch |= state << 6;
+
+	m_bus->irq6_w(state);
+}

src/devices/bus/mc68000/floppy.h

@@ -0,0 +1,48 @@
+// license: BSD-3-Clause
+// copyright-holders: Dirk Best
+/***************************************************************************
+
+    mc-68000-Computer Floppy Interface Card
+
+***************************************************************************/
+
+#ifndef MAME_BUS_MC68000_FLOPPY_H
+#define MAME_BUS_MC68000_FLOPPY_H
+
+#pragma once
+
+#include "sysbus.h"
+#include "machine/wd_fdc.h"
+#include "imagedev/floppy.h"
+
+
+class mc68000_floppy_device : public device_t, public device_mc68000_sysbus_card_interface
+{
+public:
+	// construction/destruction
+	mc68000_floppy_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
+
+	virtual uint16_t floppy_r(offs_t offset, uint16_t mem_mask = ~0) override;
+	virtual void floppy_w(offs_t offset, uint16_t data, uint16_t mem_mask = ~0) override;
+
+protected:
+	// device_t implementation
+	virtual void device_add_mconfig(machine_config &config) override;
+	virtual void device_start() override;
+	virtual void device_reset() override;
+
+private:
+	required_device<fd1793_device> m_fdc;
+	required_device_array<floppy_connector, 8> m_floppy;
+
+	uint8_t m_latch;
+
+	void intrq_w(int state);
+	void drq_w(int state);
+};
+
+// device type definition
+DECLARE_DEVICE_TYPE(MC68000_FLOPPY, mc68000_floppy_device)
+
+
+#endif // MAME_BUS_MC68000_FLOPPY_H

src/devices/bus/mc68000/sysbus.cpp

@@ -80,6 +80,24 @@ void mc68000_sysbus_device::slot_w(int slot, offs_t offset, uint16_t data, uint1
 		logerror("Write to unused slot %d: %06x = %04x & %04x\n", slot, offset, data, mem_mask);
 }
 
+uint16_t mc68000_sysbus_device::floppy_r(offs_t offset, uint16_t mem_mask)
+{
+	uint16_t data = 0xffff;
+
+	for (int i = 0; i < 8; i++)
+		if (m_device_list[i])
+			data &= m_device_list[i]->floppy_r(offset, mem_mask);
+
+	return data;
+}
+
+void mc68000_sysbus_device::floppy_w(offs_t offset, uint16_t data, uint16_t mem_mask)
+{
+	for (int i = 0; i < 8; i++)
+		if (m_device_list[i])
+			m_device_list[i]->floppy_w(offset, data, mem_mask);
+}
+
 
 //**************************************************************************
 //  SLOT DEVICE

src/devices/bus/mc68000/sysbus.h

@@ -85,6 +85,9 @@ public:
 	uint16_t slot_r(int slot, offs_t offset, uint16_t mem_mask = ~0);
 	void slot_w(int slot, offs_t offset, uint16_t data, uint16_t mem_mask = ~0);
 
+	uint16_t floppy_r(offs_t offset, uint16_t mem_mask = ~0);
+	void floppy_w(offs_t offset, uint16_t data, uint16_t mem_mask = ~0);
+
 protected:
 	// device_t implementation
 	virtual void device_start() override;
@@ -153,6 +156,9 @@ public:
 	virtual uint16_t slot_r(offs_t offset, uint16_t mem_mask = ~0) { return 0xffff; }
 	virtual void slot_w(offs_t offset, uint16_t data, uint16_t mem_mask = ~0) { }
 
+	virtual uint16_t floppy_r(offs_t offset, uint16_t mem_mask = ~0) { return 0xffff; }
+	virtual void floppy_w(offs_t offset, uint16_t data, uint16_t mem_mask = ~0) { }
+
 protected:
 	device_mc68000_sysbus_card_interface(const machine_config &mconfig, device_t &device);
 

src/mame/mc/mc68000.cpp

@@ -14,7 +14,6 @@
 
     TODO:
     - Better keyboard
-    - Floppy
     - Cassette
     - Color/brightness levels
     - Sound
@@ -46,7 +45,7 @@
 #define LOG_IO_READ  (1U << 1)
 #define LOG_IO_WRITE (1U << 2)
 
-#define VERBOSE (LOG_GENERAL | LOG_IO_WRITE)
+//#define VERBOSE (LOG_GENERAL | LOG_IO_WRITE | LOG_IO_READ)
 #include "logmacro.h"
 
 
@@ -167,8 +166,7 @@ uint16_t mc68000_state::memory_r(offs_t offset, uint16_t mem_mask)
 			break;
 
 		case 2:
-			LOGMASKED(LOG_IO_READ, "Unhandled floppy access\n");
-			data = 0xffff;
+			data = m_sysbus->floppy_r(offset >> 1, mem_mask);
 			break;
 
 		case 3:
@@ -259,7 +257,7 @@ void mc68000_state::memory_w(offs_t offset, uint16_t data, uint16_t mem_mask)
 			break;
 
 		case 2:
-			LOGMASKED(LOG_IO_WRITE, "Unhandled floppy access\n");
+			m_sysbus->floppy_w(offset >> 1, data, mem_mask);
 			break;
 
 		case 3: