Preliminary emulation of ASC-88 SCSI adapter [AJR, minuszerodegrees.net]

scripts/src/bus.lua

@@ -1359,6 +1359,8 @@ if (BUSES["ISA"]~=null) then
 		MAME_DIR .. "src/devices/bus/isa/ultra24f.h",
 		MAME_DIR .. "src/devices/bus/isa/tekram_dc820.cpp",
 		MAME_DIR .. "src/devices/bus/isa/tekram_dc820.h",
+		MAME_DIR .. "src/devices/bus/isa/asc88.cpp",
+		MAME_DIR .. "src/devices/bus/isa/asc88.h",
 	}
 end
 

src/devices/bus/isa/asc88.cpp

@@ -0,0 +1,184 @@
+// license:BSD-3-Clause
+// copyright-holders:AJR
+/***************************************************************************
+
+    ASC-88 SCSI Adapter
+    © 1985 Advanced Storage Concepts, Inc.
+
+***************************************************************************/
+
+#include "emu.h"
+#include "asc88.h"
+
+#include "machine/nscsi_bus.h"
+#include "machine/nscsi_hd.h"
+
+
+DEFINE_DEVICE_TYPE(ASC88, asc88_device, "asc88", "ASC-88 SCSI Adapter")
+
+
+asc88_device::asc88_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
+	: device_t(mconfig, ASC88, tag, owner, clock)
+	, device_isa8_card_interface(mconfig, *this)
+	, m_scsic(*this, "scsi:7:scsic")
+	, m_eeprom(*this, "eeprom")
+	, m_baseaddr(*this, "BASEADDR")
+	, m_control(0)
+	, m_irq(false)
+	, m_drq(false)
+{
+}
+
+void asc88_device::device_start()
+{
+	set_isa_device();
+
+	m_ram = make_unique_clear<u8[]>(0x800);
+
+	save_item(NAME(m_control));
+	save_item(NAME(m_irq));
+	save_item(NAME(m_drq));
+	save_pointer(NAME(m_ram), 0x800);
+}
+
+void asc88_device::device_reset()
+{
+	const offs_t baseaddr = 0xc0000 | (u32(m_baseaddr->read()) << 14);
+	m_isa->install_rom(this, baseaddr, baseaddr | 0x37ff, "asc88", "bios");
+	m_isa->install_bank(baseaddr | 0x3800, baseaddr | 0x3fef, "ascram", m_ram.get());
+	m_isa->install_memory(baseaddr | 0x3ff0, baseaddr | 0x3ff7,
+		read8sm_delegate(FUNC(ncr5380n_device::read), &*m_scsic),
+		write8sm_delegate(FUNC(ncr5380n_device::write), &*m_scsic));
+	m_isa->install_memory(baseaddr | 0x3ff8, baseaddr | 0x3ff8,
+		read8smo_delegate(FUNC(asc88_device::eeprom_r), this),
+		write8smo_delegate(FUNC(asc88_device::control_w), this));
+
+	control_w(0);
+}
+
+WRITE_LINE_MEMBER(asc88_device::irq_w)
+{
+	if (m_irq != state)
+	{
+		m_irq = state;
+		if (BIT(m_control, 3))
+			m_isa->irq2_w(state);
+		if (BIT(m_control, 4))
+			m_isa->irq3_w(state);
+		if (BIT(m_control, 5))
+			m_isa->irq5_w(state);
+	}
+}
+
+WRITE_LINE_MEMBER(asc88_device::drq_w)
+{
+	if (m_drq != state)
+	{
+		m_drq = state;
+		if (BIT(m_control, 6))
+			m_isa->drq1_w(state);
+		if (BIT(m_control, 7))
+			m_isa->drq3_w(state);
+	}
+}
+
+u8 asc88_device::dack_r(int line)
+{
+	return m_scsic->dma_r();
+}
+
+void asc88_device::dack_w(int line, u8 data)
+{
+	m_scsic->dma_w(data);
+}
+
+void asc88_device::control_w(u8 data)
+{
+	const u8 changing_bits = data ^ m_control;
+	m_control = data;
+
+	m_eeprom->di_write(BIT(data, 0));
+	m_eeprom->clk_write(BIT(data, 1));
+	m_eeprom->cs_write(BIT(data, 2));
+
+	if (m_irq)
+	{
+		if (BIT(m_control, 3))
+			m_isa->irq2_w(BIT(data, 3));
+		if (BIT(m_control, 4))
+			m_isa->irq3_w(BIT(data, 4));
+		if (BIT(m_control, 5))
+			m_isa->irq5_w(BIT(data, 5));
+	}
+
+	if (m_drq)
+	{
+		if (BIT(changing_bits, 6))
+			m_isa->drq1_w(BIT(data, 6));
+		if (BIT(changing_bits, 7))
+			m_isa->drq3_w(BIT(data, 7));
+	}
+}
+
+u8 asc88_device::eeprom_r()
+{
+	return m_eeprom->do_read();
+}
+
+static INPUT_PORTS_START(asc88)
+	PORT_START("BASEADDR")
+	PORT_DIPNAME(0x7, 0x3, "BIOS Segment Address") PORT_DIPLOCATION("A16-A14:!1,!2,!3")
+	// For each jumper, pins 1 & 2 closed = off (0); pins 2 & 3 closed = on (1)
+	PORT_DIPSETTING(0x0, "C000h")
+	PORT_DIPSETTING(0x1, "C400h")
+	PORT_DIPSETTING(0x2, "C800h")
+	PORT_DIPSETTING(0x3, "CC00h")
+	PORT_DIPSETTING(0x4, "D000h")
+	PORT_DIPSETTING(0x5, "D400h")
+	PORT_DIPSETTING(0x6, "D800h")
+	PORT_DIPSETTING(0x7, "DC00h")
+INPUT_PORTS_END
+
+ioport_constructor asc88_device::device_input_ports() const
+{
+	return INPUT_PORTS_NAME(asc88);
+}
+
+static void asc88_scsi_devices(device_slot_interface &device)
+{
+	device.option_add("harddisk", NSCSI_HARDDISK);
+	device.option_add_internal("scsic", NCR5380N);
+}
+
+void asc88_device::scsic_config(device_t *device)
+{
+	device->set_clock(10'000'000); // FIXME: this clock is fake
+	downcast<ncr5380n_device &>(*device).irq_handler().set("^^", FUNC(asc88_device::irq_w));
+	downcast<ncr5380n_device &>(*device).drq_handler().set("^^", FUNC(asc88_device::drq_w));
+}
+
+void asc88_device::device_add_mconfig(machine_config &config)
+{
+	NSCSI_BUS(config, "scsi");
+	NSCSI_CONNECTOR(config, "scsi:0", asc88_scsi_devices, nullptr);
+	NSCSI_CONNECTOR(config, "scsi:1", asc88_scsi_devices, nullptr);
+	NSCSI_CONNECTOR(config, "scsi:2", asc88_scsi_devices, nullptr);
+	NSCSI_CONNECTOR(config, "scsi:3", asc88_scsi_devices, nullptr);
+	NSCSI_CONNECTOR(config, "scsi:4", asc88_scsi_devices, nullptr);
+	NSCSI_CONNECTOR(config, "scsi:5", asc88_scsi_devices, nullptr);
+	NSCSI_CONNECTOR(config, "scsi:6", asc88_scsi_devices, nullptr);
+	NSCSI_CONNECTOR(config, "scsi:7", asc88_scsi_devices, "scsic", true)
+		.set_option_machine_config("scsic", [this] (device_t *device) { scsic_config(device); });
+
+	EEPROM_93C06_16BIT(config, m_eeprom); // NMC9306N
+}
+
+ROM_START(asc88)
+	ROM_REGION(0x3800, "bios", ROMREGION_ERASE00)
+	ROM_LOAD("asc88_rev._4.0n_14-nov-91.u14", 0x0000, 0x2000, CRC(8657d1bf) SHA1(49c44aafbb3f28478e4b5eeaa208b147fdf253b9)) // TMS27C64-IJL
+ROM_END
+
+const tiny_rom_entry *asc88_device::device_rom_region() const
+{
+	return ROM_NAME(asc88);
+}

src/devices/bus/isa/asc88.h

@@ -0,0 +1,56 @@
+// license:BSD-3-Clause
+// copyright-holders:AJR
+/***************************************************************************
+
+    ASC-88 SCSI Adapter
+    © 1985 Advanced Storage Concepts, Inc.
+
+***************************************************************************/
+
+#ifndef MAME_BUS_ISA_ASC88_H
+#define MAME_BUS_ISA_ASC88_H 1
+
+#pragma once
+
+#include "isa.h"
+#include "machine/eepromser.h"
+#include "machine/ncr5380n.h"
+
+class asc88_device : public device_t, public device_isa8_card_interface
+{
+public:
+	asc88_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock);
+
+protected:
+	virtual void device_start() override;
+	virtual void device_reset() override;
+	virtual ioport_constructor device_input_ports() const override;
+	virtual void device_add_mconfig(machine_config &config) override;
+	virtual const tiny_rom_entry *device_rom_region() const override;
+
+	virtual u8 dack_r(int line) override;
+	virtual void dack_w(int line, u8 data) override;
+
+private:
+	DECLARE_WRITE_LINE_MEMBER(irq_w);
+	DECLARE_WRITE_LINE_MEMBER(drq_w);
+
+	void control_w(u8 data);
+	u8 eeprom_r();
+
+	void scsic_config(device_t *device);
+
+	required_device<ncr5380n_device> m_scsic;
+	required_device<eeprom_serial_93cxx_device> m_eeprom;
+	required_ioport m_baseaddr;
+
+	u8 m_control;
+	bool m_irq;
+	bool m_drq;
+	std::unique_ptr<u8[]> m_ram;	
+};
+
+// device type declaration
+DECLARE_DEVICE_TYPE(ASC88, asc88_device)
+
+#endif // MAME_BUS_ISA_ASC88_H

src/devices/bus/isa/isa_cards.cpp

@@ -45,6 +45,7 @@
 #include "ultra14f.h"
 #include "ultra24f.h"
 #include "tekram_dc820.h"
+#include "asc88.h"
 
 // sound
 #include "adlib.h"
@@ -120,6 +121,7 @@ void pc_isa8_cards(device_slot_interface &device)
 	device.option_add("dectalk", ISA8_DECTALK);
 	device.option_add("pds", ISA8_PDS);
 	device.option_add("lba_enhancer", ISA8_LBA_ENHANCER);
+	device.option_add("asc88", ASC88);
 }
 
 void pc_isa16_cards(device_slot_interface &device)