diff --git a/scripts/src/machine.lua b/scripts/src/machine.lua
index d2191f1c87a..264664d259f 100644
--- a/scripts/src/machine.lua
+++ b/scripts/src/machine.lua
@@ -824,6 +824,18 @@ if (MACHINES["AMIGAFDC"]~=null) then
 	}
 end
 
+---------------------------------------------------
+--
+--@src/devices/machine/applepic.h,MACHINES["APPLEPIC"] = true
+---------------------------------------------------
+
+if (MACHINES["APPLEPIC"]~=null) then
+	files {
+		MAME_DIR .. "src/devices/machine/applepic.cpp",
+		MAME_DIR .. "src/devices/machine/applepic.h",
+	}
+end
+
 ---------------------------------------------------
 --
 --@src/devices/machine/at28c16.h,MACHINES["AT28C16"] = true
diff --git a/scripts/target/mame/arcade.lua b/scripts/target/mame/arcade.lua
index b818768ea76..9cf5b78f06d 100644
--- a/scripts/target/mame/arcade.lua
+++ b/scripts/target/mame/arcade.lua
@@ -457,6 +457,7 @@ MACHINES["AM79C90"] = true
 --MACHINES["AM9513"] = true
 MACHINES["AM9517A"] = true
 MACHINES["AMIGAFDC"] = true
+--MACHINES["APPLEPIC"] = true
 MACHINES["AT_KEYBC"] = true
 MACHINES["AT28C16"] = true
 --MACHINES["AT28C64B"] = true
diff --git a/scripts/target/mame/mess.lua b/scripts/target/mame/mess.lua
index 4ef88975da0..ff4bea4f494 100644
--- a/scripts/target/mame/mess.lua
+++ b/scripts/target/mame/mess.lua
@@ -479,6 +479,7 @@ MACHINES["AM9513"] = true
 MACHINES["AM9517A"] = true
 MACHINES["AM9519"] = true
 MACHINES["AMIGAFDC"] = true
+MACHINES["APPLEPIC"] = true
 MACHINES["ARM_IOMD"] = true
 MACHINES["AT_KEYBC"] = true
 MACHINES["AT28C16"] = true
diff --git a/src/devices/machine/applefdintf.cpp b/src/devices/machine/applefdintf.cpp
old mode 100755
new mode 100644
diff --git a/src/devices/machine/applefdintf.h b/src/devices/machine/applefdintf.h
old mode 100755
new mode 100644
diff --git a/src/mame/drivers/mac.cpp b/src/mame/drivers/mac.cpp
index 6d02f92276b..d038a4007fe 100644
--- a/src/mame/drivers/mac.cpp
+++ b/src/mame/drivers/mac.cpp
@@ -17,6 +17,7 @@
 #include "cpu/m68000/m68000.h"
 #include "cpu/m6805/m6805.h"
 #include "formats/ap_dsk35.h"
+#include "machine/applepic.h"
 #include "machine/iwm.h"
 #include "machine/swim1.h"
 #include "machine/swim2.h"
@@ -394,6 +395,44 @@ void mac_state::biu_w(offs_t offset, uint32_t data, uint32_t mem_mask)
 //  printf("biu_w %x @ %x, mask %08x\n", data, offset, mem_mask);
 }
 
+template <int N> WRITE_LINE_MEMBER(mac_state::oss_interrupt)
+{
+	if (state == ASSERT_LINE)
+		m_oss_regs[N >= 8 ? 0x202 : 0x203] |= 1 << (N & 7);
+	else
+		m_oss_regs[N >= 8 ? 0x202 : 0x203] &= ~(1 << (N & 7));
+
+	int take_interrupt = 0;
+	for (int n = 0; n < 8; n++)
+	{
+		if (BIT(m_oss_regs[0x203], n) && take_interrupt < m_oss_regs[n])
+			take_interrupt = m_oss_regs[n];
+		if (BIT(m_oss_regs[0x202], n) && take_interrupt < m_oss_regs[8 + n])
+			take_interrupt = m_oss_regs[8 + n];
+	}
+
+	if (m_last_taken_interrupt > -1)
+	{
+		m_maincpu->set_input_line(m_last_taken_interrupt, CLEAR_LINE);
+		m_last_taken_interrupt = -1;
+		m_oss_regs[0x200] &= 0x7f;
+	}
+
+	if (take_interrupt > 0)
+	{
+		m_maincpu->set_input_line(take_interrupt, ASSERT_LINE);
+		m_last_taken_interrupt = take_interrupt;
+		m_oss_regs[0x200] |= 0x80;
+	}
+}
+
+TIMER_CALLBACK_MEMBER(mac_state::oss_6015_tick)
+{
+	m_via1->write_ca1(0);
+	m_via1->write_ca1(1);
+	oss_interrupt<10>(ASSERT_LINE);
+}
+
 uint8_t mac_state::oss_r(offs_t offset)
 {
 //  printf("oss_r @ %x\n", offset);
@@ -402,13 +441,19 @@ uint8_t mac_state::oss_r(offs_t offset)
 //      return m_oss_regs[offset]<<4;
 //  }
 
-	return m_oss_regs[offset];
+	if (offset < std::size(m_oss_regs))
+		return m_oss_regs[offset];
+	else
+		return 0;
 }
 
 void mac_state::oss_w(offs_t offset, uint8_t data)
 {
 //  printf("oss_w %x @ %x\n", data, offset);
-	m_oss_regs[offset] = data;
+	if (offset == 0x207)
+		oss_interrupt<10>(CLEAR_LINE);
+	else if (offset < std::size(m_oss_regs))
+		m_oss_regs[offset] = data;
 }
 
 uint32_t mac_state::buserror_r()
@@ -418,28 +463,11 @@ uint32_t mac_state::buserror_r()
 	return 0;
 }
 
-uint8_t mac_state::scciop_r(offs_t offset)
+uint8_t mac_state::maciifx_unknown_r()
 {
-//  printf("scciop_r @ %x (PC=%x)\n", offset, m_maincpu->pc());
 	return 0;
 }
 
-void mac_state::scciop_w(offs_t offset, uint8_t data)
-{
-//  printf("scciop_w %x @ %x (PC=%x)\n", data, offset, m_maincpu->pc());
-}
-
-uint8_t mac_state::swimiop_r(offs_t offset)
-{
-//  printf("swimiop_r @ %x (PC=%x)\n", offset, m_maincpu->pc());
-	return 0;
-}
-
-void mac_state::swimiop_w(offs_t offset, uint8_t data)
-{
-//  printf("swimiop_w %x @ %x (PC=%x)\n", data, offset, m_maincpu->pc());
-}
-
 /***************************************************************************
     ADDRESS MAPS
 ***************************************************************************/
@@ -539,13 +567,16 @@ void mac_state::maciifx_map(address_map &map)
 	map(0x40000000, 0x4007ffff).rom().region("bootrom", 0).mirror(0x0ff80000);
 
 	map(0x50000000, 0x50001fff).rw(FUNC(mac_state::mac_via_r), FUNC(mac_state::mac_via_w)).mirror(0x00f00000);
-	map(0x50004000, 0x50005fff).rw(FUNC(mac_state::scciop_r), FUNC(mac_state::scciop_w)).mirror(0x00f00000);
+	map(0x50004000, 0x50005fff).rw("sccpic", FUNC(applepic_device::host_r), FUNC(applepic_device::host_w)).mirror(0x00f00000).umask32(0xff00ff00);
+	map(0x50004000, 0x50005fff).rw("sccpic", FUNC(applepic_device::host_r), FUNC(applepic_device::host_w)).mirror(0x00f00000).umask32(0x00ff00ff);
+	map(0x50008040, 0x50008040).r(FUNC(mac_state::maciifx_unknown_r)).mirror(0x00f00000);
 	map(0x5000a000, 0x5000bfff).rw(FUNC(mac_state::macplus_scsi_r), FUNC(mac_state::macii_scsi_w)).mirror(0x00f00000);
 	map(0x5000c060, 0x5000c063).r(FUNC(mac_state::macii_scsi_drq_r)).mirror(0x00f00000);
 	map(0x5000d000, 0x5000d003).w(FUNC(mac_state::macii_scsi_drq_w)).mirror(0x00f00000);
 	map(0x5000d060, 0x5000d063).r(FUNC(mac_state::macii_scsi_drq_r)).mirror(0x00f00000);
 	map(0x50010000, 0x50011fff).rw(m_asc, FUNC(asc_device::read), FUNC(asc_device::write)).mirror(0x00f00000);
-	map(0x50012000, 0x50013fff).rw(FUNC(mac_state::swimiop_r), FUNC(mac_state::swimiop_w)).mirror(0x00f00000);
+	map(0x50012000, 0x50013fff).rw("swimpic", FUNC(applepic_device::host_r), FUNC(applepic_device::host_w)).mirror(0x00f00000).umask32(0xff00ff00);
+	map(0x50012000, 0x50013fff).rw("swimpic", FUNC(applepic_device::host_r), FUNC(applepic_device::host_w)).mirror(0x00f00000).umask32(0x00ff00ff);
 	map(0x50018000, 0x50019fff).rw(FUNC(mac_state::biu_r), FUNC(mac_state::biu_w)).mirror(0x00f00000);
 	map(0x5001a000, 0x5001bfff).rw(FUNC(mac_state::oss_r), FUNC(mac_state::oss_w)).mirror(0x00f00000);
 	map(0x50024000, 0x50027fff).r(FUNC(mac_state::buserror_r)).mirror(0x00f00000);   // must bus error on access here so ROM can determine we're an FMC
@@ -824,13 +855,32 @@ void mac_state::maciifx(machine_config &config)
 	add_base_devices(config, true, 1);
 	add_scsi(config);
 
+	m_asc->irqf_callback().set(FUNC(mac_state::oss_interrupt<8>));
+	subdevice<nscsi_connector>("scsi:7")->set_option_machine_config("ncr5380", [this](device_t *device) {
+		ncr53c80_device &adapter = downcast<ncr53c80_device &>(*device);
+		adapter.irq_handler().set(*this, FUNC(mac_state::oss_interrupt<9>));
+		adapter.drq_handler().set(m_scsihelp, FUNC(mac_scsi_helper_device::drq_w));
+	});
+
 	R65NC22(config, m_via1, C7M/10);
 	m_via1->readpa_handler().set(FUNC(mac_state::mac_via_in_a));
 	m_via1->readpb_handler().set(FUNC(mac_state::mac_via_in_b_ii));
 	m_via1->writepa_handler().set(FUNC(mac_state::mac_via_out_a));
 	m_via1->writepb_handler().set(FUNC(mac_state::mac_via_out_b));
 	m_via1->cb2_handler().set(FUNC(mac_state::mac_adb_via_out_cb2));
-	m_via1->irq_handler().set(FUNC(mac_state::mac_via_irq));
+	m_via1->irq_handler().set(FUNC(mac_state::oss_interrupt<11>));
+
+	applepic_device &sccpic(APPLEPIC(config, "sccpic", C15M));
+	sccpic.prd_callback().set(m_scc, FUNC(scc8530_legacy_device::reg_r));
+	sccpic.pwr_callback().set(m_scc, FUNC(scc8530_legacy_device::reg_w));
+	sccpic.hint_callback().set(FUNC(mac_state::oss_interrupt<7>));
+
+	m_scc->intrq_callback().set("sccpic", FUNC(applepic_device::pint_w));
+
+	applepic_device &swimpic(APPLEPIC(config, "swimpic", C15M));
+	swimpic.prd_callback().set(m_fdc, FUNC(applefdintf_device::read));
+	swimpic.pwr_callback().set(m_fdc, FUNC(applefdintf_device::write));
+	swimpic.hint_callback().set(FUNC(mac_state::oss_interrupt<6>));
 
 	RAM(config, m_ram);
 	m_ram->set_default_size("4M");
@@ -839,6 +889,13 @@ void mac_state::maciifx(machine_config &config)
 	SOFTWARE_LIST(config, "flop35_list").set_original("mac_flop");
 
 	add_nubus(config);
+	nubus_device &nubus(*subdevice<nubus_device>("nubus"));
+	nubus.out_irq9_callback().set(FUNC(mac_state::oss_interrupt<0>));
+	nubus.out_irqa_callback().set(FUNC(mac_state::oss_interrupt<1>));
+	nubus.out_irqb_callback().set(FUNC(mac_state::oss_interrupt<2>));
+	nubus.out_irqc_callback().set(FUNC(mac_state::oss_interrupt<3>));
+	nubus.out_irqd_callback().set(FUNC(mac_state::oss_interrupt<4>));
+	nubus.out_irqe_callback().set(FUNC(mac_state::oss_interrupt<5>));
 }
 
 void mac_state::maclc(machine_config &config, bool cpu, bool egret, asc_device::asc_type asc_type, int woz_version)
diff --git a/src/mame/includes/mac.h b/src/mame/includes/mac.h
index ecd34dd8921..debf268d3db 100644
--- a/src/mame/includes/mac.h
+++ b/src/mame/includes/mac.h
@@ -306,13 +306,12 @@ private:
 
 	uint32_t biu_r(offs_t offset, uint32_t mem_mask = ~0);
 	void biu_w(offs_t offset, uint32_t data, uint32_t mem_mask = ~0);
+	template <int N> DECLARE_WRITE_LINE_MEMBER(oss_interrupt);
+	TIMER_CALLBACK_MEMBER(oss_6015_tick);
 	uint8_t oss_r(offs_t offset);
 	void oss_w(offs_t offset, uint8_t data);
 	uint32_t buserror_r();
-	uint8_t swimiop_r(offs_t offset);
-	void swimiop_w(offs_t offset, uint8_t data);
-	uint8_t scciop_r(offs_t offset);
-	void scciop_w(offs_t offset, uint8_t data);
+	uint8_t maciifx_unknown_r();
 
 	DECLARE_WRITE_LINE_MEMBER(nubus_irq_9_w);
 	DECLARE_WRITE_LINE_MEMBER(nubus_irq_a_w);
diff --git a/src/mame/machine/mac.cpp b/src/mame/machine/mac.cpp
index 1070ecaaa5d..6e0421e293f 100644
--- a/src/mame/machine/mac.cpp
+++ b/src/mame/machine/mac.cpp
@@ -1029,7 +1029,10 @@ void mac_state::machine_start()
 		m_adbupdate_timer->adjust(attotime::from_hz(70));
 	}
 
-	m_6015_timer = machine().scheduler().timer_alloc(timer_expired_delegate(FUNC(mac_state::mac_6015_tick),this));
+	if (m_model != MODEL_MAC_IIFX)
+		m_6015_timer = machine().scheduler().timer_alloc(timer_expired_delegate(FUNC(mac_state::mac_6015_tick),this));
+	else
+		m_6015_timer = machine().scheduler().timer_alloc(timer_expired_delegate(FUNC(mac_state::oss_6015_tick),this));
 	m_6015_timer->adjust(attotime::never);
 }
 
@@ -1046,7 +1049,7 @@ void mac_state::machine_reset()
 	m_rbv_vbltime = 0;
 
 	// start 60.15 Hz timer for most systems
-	if (((m_model >= MODEL_MAC_IICI) && (m_model <= MODEL_MAC_IIVI)) || (m_model >= MODEL_MAC_LC))
+	if (((m_model >= MODEL_MAC_IICI) && (m_model <= MODEL_MAC_IIFX)) || (m_model >= MODEL_MAC_LC))
 	{
 		m_6015_timer->adjust(attotime::from_hz(60.15), 0, attotime::from_hz(60.15));
 	}