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+// license:BSD-3-Clause
+// copyright-holders:Angelo Salese, Olivier Galibert
+/**************************************************************************************************
+
+ NEC PC-80S31(K) Mini Disk Unit
+
+ Z80 + μPD765 + PPI that connects in cross with an host PPI
+
+ "Mini" as compared to the PC-8881 8-inch floppy I/F
+
+ Design is decidedly derived from Epson TF-20 and friends,
+ cfr. devices/bus/epson_sio/tf20.cpp
+
+ TODO:
+ - What's PC-80S32? Is it the 88VA version or a different beast?
+ - PC=0x7dd reads from FDC bit 3 in ST3 (twosid_r fn),
+ expecting a bit 3 high for all the PC8001 games otherwise keeps looping and eventually dies.
+ Are those incorrectly identified as 2DD? Hacked to work for now;
+ - set_input_line_vector fn doesn't work properly when issued from a device_reset,
+ we currently just implement the irq_callback instead;
+ - Bus option;
+ - Cascade mode, i.e. the CN2 connector used to accept a second disk unit for drive 2 & 3;
+ - pc80s31k: verify that irq vector write (I/O port $f0) belongs here or just
+ whatever PC88VA uses.
+ - printer interface (used for debugging? 4-bit serial?)
+ - Pinpoint what host I/O ports $f6, $f7 truly are
+ (direct FDC access from this device or a different beast? cfr. play6lim with pc8001mk2)
+ - filemst tries to access undocumented I/O port $09 at PC=5000:
+ \- If that's 0 then it tries to read a vector at [0x8000];
+ \- It then tries to read at memory [0xc0ff], set the value read in [0xf012];
+ \- Expects that ROM [0x0000] is not equal to 0xc3;
+ Bottom line: Is it trying to access some custom HW?
+
+===================================================================================================
+
+PCB (PC-80S31K)
+
+===================================================================================================
+
+ |--------------------------------------|
+ | P1 P2 P3 X1 |
+ | |
+ | CN2 |
+ | B6102C022 |
+ | FD1 FD2 (**) |
+ | | | |
+ | CN1 ------- D765AC D2364EC (*)|
+ | (*)|
+ | D8255AC-2 B6101C017 D780C-1 |
+ | |
+ |--------------------------------------|
+
+ PCB is marked PC-80S31KFDC NEC-14T
+ P1, P2, P3 are power supplies (+5V, +12V, -5V for P1, lacks -5V for the other two)
+ μPD2364EC is at position IC13, it's a 8192 size ROM. (***)
+ (*) are μPD41416C
+ (**) marked as JP, unpopulated x 3;
+ μPB6101/2 are bipolar TTL gate arrays, presumably
+ Cannot read marking of X1 (8 MHz?)
+
+ (***) Given this, we guess that PC80S31 is the 2D version while the 'K
+ variant is the 2D/2DD/2HD version.
+
+===================================================================================================
+
+Command Protocol
+
+===================================================================================================
+
+Command & parameters are normally communicated from Host via port B
+(read on port A on FDC side)
+An RPi implementation can be seen at https://github.com/MinatsuT/RPi_PC-80S31
+
+[0x00] Initialize
+[0x01] Write to disk
+ %1 number of sectors
+ %2 drive number
+ %3 track number
+ %4 sector number +1
+[0x02] Read from disk
+ %1 number of sectors
+ %2 drive number
+ %3 track number
+ %4 sector number +1
+[0x03] Send data to host
+[0x04] Copy data in-place
+ %1 number of sectors
+ %2 source drive
+ %3 source track
+ %4 source sector number +1
+ %5 destination drive
+ %6 destination track
+ %7 destination sector number +1
+[0x05] Format
+ %1 drive number
+[0x06] Send result status to Host
+ x--- ---- I/O complete
+ -x-- ---- has unread buffer
+ ---- ---x error occurred
+[0x07] Drive status
+[0x0b] Send memory data
+%1-%2 address start
+%3-%4 length
+[0x11] Fast write to disk
+ %1 number of sectors
+ %2 drive number
+ %3 track number
+ %4 sector number +1
+[0x12] Fast send data
+ (picks up number of sector etc. from previous issued commands?)
+[0x14] Device status
+ x--- ---- ESIG: error
+ -x-- ---- WPDR: write protected
+ --x- ---- RDY: ready
+ ---x ---- TRK0: track 0
+ ---- x--- DSDR: double sided drive
+ ---- -x-- HDDR: head
+ ---- --xx DS1, DS2: drive select
+ (same as 765 ST3?)
+[0x17] Mode change
+ %1 ---- xxxx mode select
+
+FDC normally puts ST0-1-2 to RAM buffers $7f0d-f, CHRN data in $7f10-13
+
+===================================================================================================
+
+Port C
+Used as a communication protocol flags
+
+===================================================================================================
+
+ Host side
+ (swap 4-bit nibbles and r/w direction for FDC side, all bits are active high):
+ x--- ---- (w) ATN AtenTioN:
+ host sends a command to FDC, interrupts current one
+ (looks unconnected the other way around?)
+ -x-- ---- (w) DAC DAta aCcepted:
+ host just picked up data from FDC
+ --x- ---- (w) RFD Ready For Data:
+ host requests data from FDC
+ ---x ---- (w) DAV DAta Valid:
+ host outputs data to port B
+ ---- -x-- (r) DAC DAta aCcepted:
+ FDC has accepted data from port B
+ ---- --x- (r) RFD Ready For Data:
+ FDC requests data from host
+ ---- ---x (r) DAV DAta Valid:
+ FDC has output data to port A
+
+**************************************************************************************************/
+
+#include "emu.h"
+#include "pc80s31k.h"
+
+//#define VERBOSE 1
+#include "logmacro.h"
+
+//**************************************************************************
+// GLOBAL VARIABLES
+//**************************************************************************
+
+
+// device type definition
+DEFINE_DEVICE_TYPE(PC80S31, pc80s31_device, "pc80s31", "NEC PC-80S31 Mini Disk Unit I/F")
+DEFINE_DEVICE_TYPE(PC80S31K, pc80s31k_device, "pc80s31k", "NEC PC-80S31K Mini Disk Unit I/F")
+
+
+//**************************************************************************
+// LIVE DEVICE
+//**************************************************************************
+
+
+//-------------------------------------------------
+// pc80s31_device - constructor
+//-------------------------------------------------
+
+
+pc80s31_device::pc80s31_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock)
+ : device_t(mconfig, type, tag, owner, clock)
+ , m_fdc(*this, "fdc")
+ , m_floppy(*this, "fdc:%u", 0U)
+ , m_fdc_cpu(*this, "fdc_cpu")
+ , m_fdc_rom(*this, "fdc_rom")
+ , m_ppi_host(*this, "ppi_host")
+ , m_ppi_fdc(*this, "ppi_fdc")
+ , m_latch(*this, "latch_%u", 0U)
+{
+}
+
+
+pc80s31_device::pc80s31_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
+ : pc80s31_device(mconfig, PC80S31, tag, owner, clock)
+{
+
+}
+
+ROM_START( pc80s31 )
+ // TODO: exact identification of these
+ ROM_REGION( 0x2000, "fdc_rom", ROMREGION_ERASEFF )
+ ROM_SYSTEM_BIOS( 0, "disk", "disk BIOS" )
+ ROMX_LOAD( "disk.rom", 0x0000, 0x0800, CRC(2158d307) SHA1(bb7103a0818850a039c67ff666a31ce49a8d516f), ROM_BIOS(0) )
+ ROM_SYSTEM_BIOS( 1, "mk2fr", "mkIIFR disk BIOS" )
+ ROMX_LOAD( "mk2fr_disk.rom", 0x0000, 0x0800, CRC(2163b304) SHA1(80da2dee49d4307f00895a129a5cfeff00cf5321), ROM_BIOS(1) )
+
+ ROM_FILL( 0x7df, 1, 0x00 )
+ ROM_FILL( 0x7e0, 1, 0x00 )
+ROM_END
+
+const tiny_rom_entry *pc80s31_device::device_rom_region() const
+{
+ return ROM_NAME( pc80s31 );
+}
+
+//-------------------------------------------------
+// device_add_mconfig - device-specific machine
+// configuration addiitons
+//-------------------------------------------------
+
+void pc80s31_device::host_map(address_map &map)
+{
+ map(0, 3).rw(m_ppi_host, FUNC(i8255_device::read), FUNC(i8255_device::write));
+}
+
+void pc80s31_device::fdc_map(address_map &map)
+{
+ map(0x0000, 0x1fff).rom().region("fdc_rom", 0);
+ map(0x4000, 0x7fff).ram();
+}
+
+void pc80s31_device::fdc_io(address_map &map)
+{
+ map.unmap_value_high();
+ map.global_mask(0xff);
+// map(0x09, 0x09).r accessed by filemst (pc8801), cfr. notes
+
+// map(0xf0, 0xf0).w(FUNC(pc8801_state::fdc_irq_vector_w)); // Interrupt Opcode Port
+// map(0xf4, 0xf4).w(FUNC(pc8801_state::fdc_drive_mode_w)); // Drive mode, 2d, 2dd, 2hd
+// map(0xf6, 0xf6).nopw(); // printer related
+ map(0xf7, 0xf7).nopw(); // printer port output
+ map(0xf8, 0xf8).rw(FUNC(pc80s31_device::terminal_count_r), FUNC(pc80s31_device::motor_control_w));
+ map(0xfa, 0xfb).m(m_fdc, FUNC(upd765a_device::map));
+ map(0xfc, 0xff).rw(m_ppi_fdc, FUNC(i8255_device::read), FUNC(i8255_device::write));
+}
+
+static void pc88_floppies(device_slot_interface &device)
+{
+ // TODO: definitely not correct for base device
+ device.option_add("525hd", FLOPPY_525_HD);
+}
+
+IRQ_CALLBACK_MEMBER(pc80s31_device::irq_cb)
+{
+ return m_irq_vector;
+}
+
+void pc80s31_device::device_add_mconfig(machine_config &config)
+{
+ constexpr XTAL fdc_xtal = XTAL(4'000'000);
+ Z80(config, m_fdc_cpu, fdc_xtal);
+ m_fdc_cpu->set_addrmap(AS_PROGRAM, &pc80s31_device::fdc_map);
+ m_fdc_cpu->set_addrmap(AS_IO, &pc80s31_device::fdc_io);
+ m_fdc_cpu->set_irq_acknowledge_callback(FUNC(pc80s31_device::irq_cb));
+
+ UPD765A(config, m_fdc, XTAL(4'000'000), true, true);
+ m_fdc->intrq_wr_callback().set_inputline(m_fdc_cpu, INPUT_LINE_IRQ0);
+
+ for (auto &floppy : m_floppy)
+ {
+ FLOPPY_CONNECTOR(config, floppy, pc88_floppies, "525hd", floppy_image_device::default_mfm_floppy_formats);
+ floppy->enable_sound(true);
+ }
+
+ for (auto &latch : m_latch)
+ GENERIC_LATCH_8(config, latch);
+
+ I8255A(config, m_ppi_host);
+ m_ppi_host->in_pa_callback().set(FUNC(pc80s31_device::latch_r<0>));
+ m_ppi_host->out_pa_callback().set(FUNC(pc80s31_device::latch_w<1>));
+ m_ppi_host->in_pb_callback().set(FUNC(pc80s31_device::latch_r<2>));
+ m_ppi_host->out_pb_callback().set(FUNC(pc80s31_device::latch_w<3>));
+ m_ppi_host->in_pc_callback().set(FUNC(pc80s31_device::latch_r<4>));
+ m_ppi_host->out_pc_callback().set(FUNC(pc80s31_device::latch_w<5>));
+
+ // 8255AC-2
+ I8255A(config, m_ppi_fdc);
+ m_ppi_fdc->in_pa_callback().set(FUNC(pc80s31_device::latch_r<3>));
+ m_ppi_fdc->out_pa_callback().set(FUNC(pc80s31_device::latch_w<2>));
+ m_ppi_fdc->in_pb_callback().set(FUNC(pc80s31_device::latch_r<1>));
+ m_ppi_fdc->out_pb_callback().set(FUNC(pc80s31_device::latch_w<0>));
+ m_ppi_fdc->in_pc_callback().set(FUNC(pc80s31_device::latch_r<5>));
+ m_ppi_fdc->out_pc_callback().set(FUNC(pc80s31_device::latch_w<4>));
+}
+
+//-------------------------------------------------
+// device_timer - device-specific timers
+//-------------------------------------------------
+
+void pc80s31_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
+{
+ assert(id == 0);
+
+ m_fdc->tc_w(false);
+
+ // several games tries to scan invalid IDs from their structures, if this hits then
+ // it's possibly an attempt to scan a missing sector from the floppy structure.
+ // cfr. acrojet: the third read data command issued tries to access a CHRN of (0, 0, 16, 256)
+ // and checks at PC=500B if any of these status flags are satisfied:
+ // ST0 & 0xdf
+ // ST1 & 0xff
+ // ST2 & 0x73
+ // Data doesn't matter, it also seems to have some activity to the printer port
+ // (debugging left on?)
+ if ((u8)m_fdc_cpu->state_int(Z80_HALT) == 1)
+ {
+ logerror("%s: attempt to trigger TC while in HALT state (read ID copy protection warning)\n", machine().describe_context());
+// throw emu_fatalerror("copy protection hit");
+ }
+}
+
+//-------------------------------------------------
+// device_start - device-specific startup
+//-------------------------------------------------
+
+void pc80s31_device::device_start()
+{
+ m_tc_zero_timer = timer_alloc(0);
+
+ save_item(NAME(m_irq_vector));
+}
+
+//-------------------------------------------------
+// device_reset - device-specific reset
+//-------------------------------------------------
+
+
+void pc80s31_device::device_reset()
+{
+ m_floppy[0]->get_device()->set_rpm(300);
+ m_floppy[1]->get_device()->set_rpm(300);
+ m_fdc->set_rate(250000);
+
+ // TODO: doesn't seem to work for devices?
+ m_fdc_cpu->set_input_line_vector(0, 0);
+ m_irq_vector = 0;
+
+ m_tc_zero_timer->adjust(attotime::never);
+}
+
+
+//**************************************************************************
+// READ/WRITE HANDLERS
+//**************************************************************************
+
+// Comms are simple dual port connected in cross fashion.
+// Even at "perfect" interleave tho we need to mailbox the connections.
+// - barbatus will hang at Artec logo the first time around (works if you soft reset);
+template <unsigned N> u8 pc80s31_device::latch_r()
+{
+ const int port_mask = N & 4 ? 0x0f : 0xff;
+// machine().scheduler().synchronize();
+ return m_latch[N]->read() & port_mask;
+}
+
+template <unsigned N> void pc80s31_device::latch_w(u8 data)
+{
+ const int lower_nibble = N & 4;
+// machine().scheduler().synchronize();
+ if (lower_nibble)
+ {
+ LOG("%s: %s port C write %02x (ATN=%d DAC=%d RFD=%d DAV=%d)\n"
+ , N & 1 ? "host" : "fdc"
+ , machine().describe_context()
+ , data
+ , BIT(data, 7)
+ , BIT(data, 6)
+ , BIT(data, 5)
+ , BIT(data, 4)
+ );
+ }
+ return m_latch[N]->write(data >> lower_nibble);
+}
+
+u8 pc80s31_device::terminal_count_r(address_space &space)
+{
+ if (!machine().side_effects_disabled())
+ {
+ m_fdc->tc_w(true);
+ // TODO: accurate time of this going off
+ m_tc_zero_timer->reset();
+ m_tc_zero_timer->adjust(attotime::from_usec(50));
+ }
+ // value is meaningless (never readback)
+ // TODO: verify this being 0xff or open bus
+ return space.unmap();
+}
+
+void pc80s31_device::motor_control_w(uint8_t data)
+{
+ // FIXME: on pc80s31k device (particularly on later releases) this stays always on
+ // babylon: just spins indefinitely at PC=6d8 (using the internal routines),
+ // waiting for DAV or ATN being on. Never hits the port until a flag is issued.
+ // prajator: on idle times it spins at PC=7060, waiting for ATN and keep issuing a 0xff here.
+ // valis2: calls PC=7009 subroutine for idle, waits for ATN on.
+ // It eventually writes a 0 here, not before an extremely long time
+ // (~10000 frames!)
+ m_floppy[0]->get_device()->mon_w(!(data & 1));
+ m_floppy[1]->get_device()->mon_w(!(data & 2));
+
+ // TODO: according to docs a value of 0x07 enables precompensation to tracks 0-19, 0xf enables it on 20-39
+}
+
+//**************************************************************************
+//
+// PC80S31K device overrides
+//
+//**************************************************************************
+
+pc80s31k_device::pc80s31k_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
+ : pc80s31_device(mconfig, PC80S31K, tag, owner, clock)
+{
+
+}
+
+ROM_START( pc80s31k )
+ // TODO: exact identification of these
+ ROM_REGION( 0x2000, "fdc_rom", ROMREGION_ERASEFF )
+ ROM_SYSTEM_BIOS( 0, "ma", "MA disk BIOS")
+ ROMX_LOAD( "ma_disk.rom", 0x0000, 0x2000, CRC(a222ecf0) SHA1(79e9c0786a14142f7a83690bf41fb4f60c5c1004), ROM_BIOS(0) )
+ ROM_SYSTEM_BIOS( 1, "mk2mr", "mkIIMR disk BIOS" )
+ ROMX_LOAD( "m2mr_disk.rom", 0x0000, 0x2000, CRC(2447516b) SHA1(1492116f15c426f9796dc2bb6fcccf2656c0ca75), ROM_BIOS(1) )
+ ROM_SYSTEM_BIOS( 2, "mh", "MH disk BIOS" )
+ ROMX_LOAD( "mh_disk.rom", 0x0000, 0x2000, CRC(a222ecf0) SHA1(79e9c0786a14142f7a83690bf41fb4f60c5c1004), ROM_BIOS(2) )
+ // TODO: this may belong to PC-80S32
+ ROM_SYSTEM_BIOS( 3, "88va", "PC88VA disk BIOS")
+ ROMX_LOAD( "vasubsys.rom", 0x0000, 0x2000, CRC(08962850) SHA1(a9375aa480f85e1422a0e1385acb0ea170c5c2e0), ROM_BIOS(3) )
+ROM_END
+
+const tiny_rom_entry *pc80s31k_device::device_rom_region() const
+{
+ return ROM_NAME( pc80s31k );
+}
+
+void pc80s31k_device::drive_mode_w(uint8_t data)
+{
+ // TODO: fix implementation
+ // anything that isn't a 2D doesn't really set proper parameters in here
+ logerror("FDC drive mode %02x\n", data);
+ m_floppy[0]->get_device()->set_rpm(BIT(data, 0) ? 360 : 300);
+ m_floppy[1]->get_device()->set_rpm(BIT(data, 1) ? 360 : 300);
+
+ m_fdc->set_rate(BIT(data, 5) ? 500000 : 250000);
+}
+
+void pc80s31k_device::fdc_io(address_map &map)
+{
+ pc80s31_device::fdc_io(map);
+
+ map(0xf0, 0xf0).lw8(NAME([this] (u8 data) { m_irq_vector = data; }));
+ map(0xf4, 0xf4).w(FUNC(pc80s31k_device::drive_mode_w));
+}