/********************************************************************* a2scsi.c Implementation of the Apple II SCSI Card Schematic at: http://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Interface%20Cards/SCSI%20Controllers/Apple%20II%20SCSI%20Card/Schematics/Rev.%20C%20SCSI%20Schematic%20-%20Updated%202-23-6.jpg Notes: C0n0-C0n7 = NCR5380 registers in normal order C0n8 = pseudo-DMA read/write and DACK C0n9 = DIP switches C0na = RAM and ROM bank switching C0nb = reset 5380 C0nc = set IIgs block mode C0nd = set pseudo-DMA C0ne = read DRQ status in bit 7 In IIgs block mode, any read from C800-CBFF window fetches the next byte from the 5380's DMA port. This lets you use the 65816 MVN/MVP operations to burst-transfer up to 1K at a time. (Requires a cycle-by-cycle haltable 65816 core; don't install the GS/OS driver right now to avoid this) Pseudo-DMA works similarly to the Mac implementation; use C0n8 to read/write "DMA" bytes in that mode. *********************************************************************/ #include "a2scsi.h" #include "includes/apple2.h" #include "machine/scsibus.h" #include "machine/nscsi_cd.h" #include "machine/nscsi_hd.h" /*************************************************************************** PARAMETERS ***************************************************************************/ //************************************************************************** // GLOBAL VARIABLES //************************************************************************** const device_type A2BUS_SCSI = &device_creator; #define SCSI_ROM_REGION "scsi_rom" #define SCSI_BUS_TAG "scsibus" #define SCSI_5380_TAG "scsibus:7:ncr5380" static MACHINE_CONFIG_FRAGMENT( ncr5380 ) MCFG_DEVICE_MODIFY(DEVICE_SELF) MCFG_DEVICE_CLOCK(10000000) MCFG_NCR5380N_DRQ_HANDLER(DEVWRITELINE("^^", a2bus_scsi_device, drq_w)) MACHINE_CONFIG_END static SLOT_INTERFACE_START( scsi_devices ) SLOT_INTERFACE("cdrom", NSCSI_CDROM) SLOT_INTERFACE("harddisk", NSCSI_HARDDISK) SLOT_INTERFACE_INTERNAL("ncr5380", NCR5380N) SLOT_INTERFACE_END MACHINE_CONFIG_FRAGMENT( scsi ) MCFG_SCSIBUS_ADD("scsi") MCFG_NSCSI_BUS_ADD(SCSI_BUS_TAG) MCFG_NSCSI_ADD("scsibus:0", scsi_devices, 0, false) MCFG_NSCSI_ADD("scsibus:1", scsi_devices, 0, false) MCFG_NSCSI_ADD("scsibus:2", scsi_devices, 0, false) MCFG_NSCSI_ADD("scsibus:3", scsi_devices, 0, false) MCFG_NSCSI_ADD("scsibus:4", scsi_devices, 0, false) MCFG_NSCSI_ADD("scsibus:5", scsi_devices, 0, false) MCFG_NSCSI_ADD("scsibus:6", scsi_devices, "harddisk", false) MCFG_NSCSI_ADD("scsibus:7", scsi_devices, "ncr5380", true) MCFG_DEVICE_CARD_MACHINE_CONFIG("ncr5380", ncr5380) MACHINE_CONFIG_END ROM_START( scsi ) ROM_REGION(0x4000, SCSI_ROM_REGION, 0) // this is the Rev. C ROM ROM_LOAD( "341-0437-a.bin", 0x0000, 0x4000, CRC(5aff85d3) SHA1(451c85c46b92e6ad2ad930f055ccf0fe3049936d) ) ROM_END /*************************************************************************** FUNCTION PROTOTYPES ***************************************************************************/ //------------------------------------------------- // machine_config_additions - device-specific // machine configurations //------------------------------------------------- machine_config_constructor a2bus_scsi_device::device_mconfig_additions() const { return MACHINE_CONFIG_NAME( scsi ); } //------------------------------------------------- // rom_region - device-specific ROM region //------------------------------------------------- const rom_entry *a2bus_scsi_device::device_rom_region() const { return ROM_NAME( scsi ); } //************************************************************************** // LIVE DEVICE //************************************************************************** a2bus_scsi_device::a2bus_scsi_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, UINT32 clock, const char *shortname, const char *source) : device_t(mconfig, type, name, tag, owner, clock, shortname, source), device_a2bus_card_interface(mconfig, *this), m_ncr5380(*this, SCSI_5380_TAG), m_scsibus(*this, SCSI_BUS_TAG) { } a2bus_scsi_device::a2bus_scsi_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) : device_t(mconfig, A2BUS_SCSI, "Apple II SCSI Card", tag, owner, clock, "a2scsi", __FILE__), device_a2bus_card_interface(mconfig, *this), m_ncr5380(*this, SCSI_5380_TAG), m_scsibus(*this, SCSI_BUS_TAG) { } //------------------------------------------------- // device_start - device-specific startup //------------------------------------------------- void a2bus_scsi_device::device_start() { // set_a2bus_device makes m_slot valid set_a2bus_device(); astring tempstring; m_rom = device().machine().root_device().memregion(this->subtag(tempstring, SCSI_ROM_REGION))->base(); memset(m_ram, 0, 8192); save_item(NAME(m_ram)); save_item(NAME(m_rambank)); save_item(NAME(m_rombank)); save_item(NAME(m_bank)); save_item(NAME(m_drq)); save_item(NAME(m_816block)); } void a2bus_scsi_device::device_reset() { m_rambank = m_rombank = 0; // CLR on 74LS273 at U3E is connected to RES, so these clear on reset m_816block = false; } /*------------------------------------------------- read_c0nx - called for reads from this card's c0nx space -------------------------------------------------*/ UINT8 a2bus_scsi_device::read_c0nx(address_space &space, UINT8 offset) { switch (offset) { case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: // printf("Read 5380 @ %x\n", offset); return m_ncr5380->read(space, offset); break; case 8: // read and DACK return m_ncr5380->dma_r(); case 9: // our SCSI ID (normally 0x80 = 7) return (1<<7); case 0xa: // RAM/ROM bank return m_bank; case 0xe: // DRQ status in bit 7 return m_drq; default: printf("Read c0n%x (PC=%x)\n", offset, space.device().safe_pc()); break; } return 0xff; } /*------------------------------------------------- write_c0nx - called for writes to this card's c0nx space -------------------------------------------------*/ void a2bus_scsi_device::write_c0nx(address_space &space, UINT8 offset, UINT8 data) { switch (offset) { case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: // printf("%02x to 5380 reg %x\n", data, offset); m_ncr5380->write(space, offset, data); break; case 8: // write and DACK m_ncr5380->dma_w(data); break; case 0xa: // ROM and RAM banking (74LS273 at U3E) /* ROM banking: (bits EA8-EA13 are all zeroed when /IOSEL is asserted, so CnXX always gets the first page of the ROM) EA10 = bit 0 EA11 = bit 1 EA12 = bit 2 EA13 = bit 3 (N/C) RAM banking: RA10 = bit 4 RA11 = bit 5 RA12 = bit 6 */ m_rambank = ((data>>4) & 0x7) * 0x400; m_rombank = (data & 0xf) * 0x400; m_bank = data; // printf("RAM bank to %x, ROM bank to %x\n", m_rambank, m_rombank); m_816block = false; // does this reset block mode? break; case 0xb: // reset 5380 // printf("Resetting SCSI: %02x at %x\n", data, space.device().safe_pc()); m_ncr5380->reset(); m_816block = false; break; case 0xc: // set IIgs block mode DMA printf("%02x to block-mode DMA mode\n", data); m_816block = true; break; case 0xd: // set Mac-style pseudo-DMA // printf("%02x to pseudo-DMA mode\n", data); m_816block = false; break; default: printf("Write %02x to c0n%x (PC=%x)\n", data, offset, space.device().safe_pc()); break; } } /*------------------------------------------------- read_cnxx - called for reads from this card's cnxx space -------------------------------------------------*/ UINT8 a2bus_scsi_device::read_cnxx(address_space &space, UINT8 offset) { // one slot image at the start of the ROM, it appears return m_rom[offset]; } void a2bus_scsi_device::write_cnxx(address_space &space, UINT8 offset, UINT8 data) { // there are writes to cn0A, possibly misguided C0nA (bank select?) writes? // printf("Write %02x to cn%02x (PC=%x)\n", data, offset, space.device().safe_pc()); } /*------------------------------------------------- read_c800 - called for reads from this card's c800 space -------------------------------------------------*/ UINT8 a2bus_scsi_device::read_c800(address_space &space, UINT16 offset) { // bankswitched RAM at c800-cbff // bankswitched ROM at cc00-cfff if (offset < 0x400) { // printf("Read RAM at %x = %02x\n", offset+m_rambank, m_ram[offset + m_rambank]); if (m_816block) { return m_ncr5380->dma_r(); } return m_ram[offset + m_rambank]; } else { return m_rom[(offset-0x400) + m_rombank]; } } /*------------------------------------------------- write_c800 - called for writes to this card's c800 space -------------------------------------------------*/ void a2bus_scsi_device::write_c800(address_space &space, UINT16 offset, UINT8 data) { if (offset < 0x400) { // printf("%02x to RAM at %x\n", data, offset+m_rambank); if (m_816block) { m_ncr5380->dma_w(data); } else { m_ram[offset + m_rambank] = data; } } } WRITE_LINE_MEMBER( a2bus_scsi_device::drq_w ) { m_drq = (state ? 0x80 : 0x00); }