(nw) icebox : last update for this cycle.

src/mame/drivers/icebox.cpp

@@ -6,10 +6,10 @@ Nutting Icebox
 
 2018-08-19 Skeleton driver. It's all guesswork.
 
-It's a case with many slots for daughter boards, and 2 floppy drives. It appears to be an "in-circuit emulator"
+It's a case with many slots for daughter boards, and 2 floppy drives. It's an "in-circuit emulator"
-for an unknown arcade board.
+for Bally / Astrocade development.
 
-The unit has 5 boards: 3 boards were photographed and are: a cpu board (Z80 and unmarked XTAL),
+The unit has 5 daughter boards: 3 boards were photographed and are: a cpu board (Z80 and unmarked XTAL),
                     a RS232 board (2x 8251, 8 dipswitches connected to a BR1941L, 4.9152 XTAL),
                     and a board covered with TTL.
 
@@ -25,14 +25,80 @@ Commands:
 
 Status:
 - Machine boots up, you can enter commands.
+- Disk track 00 can be read into memory, hangs when track 01 is requested.
+- Note that disk won't actually do anything until Z-80 IM0 is fixed.
 
 To Do:
-- Find out what ports E4-FF do.
+- Find out more what ports F2-FF do.
-- Hook up the floppy drives when the ports are identified.
 
 The floppy drives are a special type containing a FDC within. The FDC is a FD1771-B01 with a 4MHz XTAL.
-I suspect the drive issues a NMI when the internal DRQ asserts (code around F21C). Need to resolve how
+
-it handles writing data to 0000-up while keeping the NMI handler.
+
+NOTES FROM AL KOSSOW
+--------------------
+
+This is the Nutting Associates ICE box used for Bally arcade and Astrocade development.
+
+The games are written in "Terse", a dialect of FORTH with graphics and sound extensions.
+
+The game graphics and sound hardware were in a separate chassis connected through 50 pin ribbon cables.
+There is 64K of ram that can be mapped to the addresses used where the proms in the game would be.
+
+Development appeared to have started under CP/M, then they migrated to development in the Terse environment.
+The sector size also changed from 128 to 1024 bytes. For some reason, the hardware inverts the sector data.
+CP/M flipped the bits, Terse does not.
+
+There is a 122 pin backplane, and five cards. The bus buffers for the floppies and the external hardware
+are on the backplane. There is an I/O, memory mapper, dual 32k static ram, and CPU cards. The I/O card has
+a three byte FIFO and a buffer for forcing 00 onto the data bus, which appears to be related to handling
+breakpoints from looking at the code in ICE.ASM.
+
+The eprom dump is for booting Terse, and earlier version of the prom is documented in ICE.ASM which may be for CP/M
+
+The CPU card has 1K of ram, mapped to FC00. They must have moved the sector buffering to main RAM, since a
+1K sector obviously wouldn't fit.
+
+The crystal on the CPU is 9.8304MHz. It may be possible to alter the cpu speed. There is a FAST signal on the bp.
+
+I/O registers from the ICE.ASM listing
+
+CRTD    E0    terminal uart data
+CRTS    E1    terminal uart control
+LPTD    E2    printer uart data
+LPTS    E3    printer uart control
+
+DATA    E4    1771 regs
+SECTOR  E5
+TRACK   E6
+COMMAND E7
+
+CENABE  F0
+SELECT  F1    bit 0 & 1 (select drive 0-3), bit 2 (enable floppy interrupt)
+FIFO    F2    3 BYTE FIFO
+
+EXTL    F8    These are probably for the mapping registers
+EXTH    F9
+
+WPROTL  FA
+WPROTH  FB
+
+BADRH   FC    BASE ADR? breakpoint
+BADRL   FD
+
+BTYPE   FE
+MISC    FF
+
+the 0 is forced onto the bus when bp signal IRESET/ is asserted. it appears to come from the CPU board (only
+the cpu and io board are connected to it)
+
+the box doesn't do remapping, it just has two 16 bit write-only registers that can unmap and write protect memory
+in 16 4k chunks, (extl,exth), (wprotl,wproth) .
+
+breakpoint (badrh, barl) specifies an adr to nmi on, with a 4 bit reference type in btype (wr, req, iorq, mreq)
+
+it looks like zeroing btype disables it.
+
+io port 0xff (misc) is on the I/O board.
 
 ******************************************************************************************************************/
 
@@ -41,8 +107,7 @@ it handles writing data to 0000-up while keeping the NMI handler.
 #include "machine/i8251.h"
 #include "machine/com8116.h"
 #include "bus/rs232/rs232.h"
-//#include "machine/wd_fdc.h"
+#include "machine/wd_fdc.h"
-#include "screen.h"
 
 
 class icebox_state : public driver_device
@@ -54,25 +119,35 @@ public:
 		, m_uart0(*this, "uart0")
 		, m_uart1(*this, "uart1")
 		, m_brg(*this, "brg")
+		, m_fdc(*this, "fdc")
+		, m_floppy0(*this, "fdc:0")
+		, m_floppy1(*this, "fdc:1")
 	{ }
 
 	void icebox(machine_config &config);
 
 private:
+	DECLARE_WRITE_LINE_MEMBER(intrq_w);
+	DECLARE_WRITE_LINE_MEMBER(drq_w);
 	void mem_map(address_map &map);
 	void io_map(address_map &map);
 	void machine_reset() override;
+	void port_f1_w(u8 data);
+	u8 m_f1;
 
 	required_device<cpu_device> m_maincpu;
 	required_device<i8251_device> m_uart0;
 	required_device<i8251_device> m_uart1;
 	required_device<com8116_device> m_brg;
+	required_device<fd1771_device> m_fdc;
+	required_device<floppy_connector> m_floppy0;
+	required_device<floppy_connector> m_floppy1;
 };
 
 
 void icebox_state::mem_map(address_map &map)
 {
-	map(0x0000, 0x00ff).rom().region("maincpu", 0); // required for NMI handler and for initial boot
+	map(0x0000, 0xefff).ram();
 	map(0xf000, 0xfbff).rom().region("maincpu", 0);
 	map(0xfc00, 0xffff).ram();
 }
@@ -81,10 +156,14 @@ void icebox_state::io_map(address_map &map)
 {
 	map.global_mask(0xff);
 	map.unmap_value_high();
-	map(0xe0, 0xe0).rw("uart0", FUNC(i8251_device::data_r), FUNC(i8251_device::data_w));
+	map(0xe0, 0xe0).rw(m_uart0, FUNC(i8251_device::data_r), FUNC(i8251_device::data_w));
-	map(0xe1, 0xe1).rw("uart0", FUNC(i8251_device::status_r), FUNC(i8251_device::control_w));
+	map(0xe1, 0xe1).rw(m_uart0, FUNC(i8251_device::status_r), FUNC(i8251_device::control_w));
-	map(0xe2, 0xe2).rw("uart1", FUNC(i8251_device::data_r), FUNC(i8251_device::data_w));
+	map(0xe2, 0xe2).rw(m_uart1, FUNC(i8251_device::data_r), FUNC(i8251_device::data_w));
-	map(0xe3, 0xe3).rw("uart1", FUNC(i8251_device::status_r), FUNC(i8251_device::control_w));
+	map(0xe3, 0xe3).rw(m_uart1, FUNC(i8251_device::status_r), FUNC(i8251_device::control_w));
+	map(0xe4, 0xe7).lrw8("fdc_usage",
+					[this](offs_t offset) { return m_fdc->read(offset^3); },
+					[this](offs_t offset, u8 data) { m_fdc->write(offset^3, data); });
+	map(0xf1, 0xf1).lw8("port_F1", [this](u8 data) { port_f1_w(data); } );
 }
 
 /* Input ports */
@@ -129,13 +208,57 @@ void icebox_state::machine_reset()
 	u8 data = ioport("BAUD")->read();
 	m_brg->write_str(data & 15); // Terminal
 	m_brg->write_stt((data >> 4) & 15); // Printer
-	//m_maincpu->set_pc(0xf000);
+	m_maincpu->set_pc(0xf000);
+	m_f1 = 0;
 }
 
-//static void xor100_floppies(device_slot_interface &device)
+void icebox_state::port_f1_w(u8 data)
-//{
+{
-//	device.option_add("flop", FLOPPY_8_SSDD); // Pertec "iCOM FD5200"
+	m_f1 = data;
-//}
+
+	floppy_image_device *floppy = nullptr;
+
+	switch (data & 7)
+	{
+		case 4:
+			floppy = m_floppy0->get_device();
+			break;
+		case 5:
+			floppy = m_floppy1->get_device();
+			break;
+		default:
+			break;
+	}
+
+	m_fdc->set_floppy(floppy);
+
+	if (floppy)
+	{
+		floppy->mon_w(0);
+		floppy->ss_w(0);            // side 0 ?
+	}
+
+	m_fdc->dden_w(1);                 // single density?
+}
+
+// Command complete: release CPU from halt, via IM0.
+WRITE_LINE_MEMBER(icebox_state::intrq_w)
+{
+	if (BIT(m_f1, 2) && state)
+		m_maincpu->set_input_line_and_vector(INPUT_LINE_IRQ0, HOLD_LINE, 0xc9);
+}
+
+// The next byte from floppy is available. Enable CPU so it can get the byte, via IM0.
+WRITE_LINE_MEMBER(icebox_state::drq_w)
+{
+	if (BIT(m_f1, 2) && state)
+		m_maincpu->set_input_line_and_vector(INPUT_LINE_IRQ0, HOLD_LINE, 0xc9);
+}
+
+static void floppies(device_slot_interface &device)
+{
+	device.option_add("flop", FLOPPY_8_SSDD); // Pertec "iCOM FD5200"
+}
 
 static DEVICE_INPUT_DEFAULTS_START( terminal ) // we need to remove bit 7 which is on the last character of each message
 	DEVICE_INPUT_DEFAULTS( "RS232_RXBAUD", 0xff, RS232_BAUD_9600 )
@@ -148,7 +271,7 @@ DEVICE_INPUT_DEFAULTS_END
 
 MACHINE_CONFIG_START(icebox_state::icebox)
 	/* basic machine hardware */
-	MCFG_DEVICE_ADD("maincpu",Z80, 2'000'000) // unknown crystal and clock
+	MCFG_DEVICE_ADD("maincpu",Z80, 9'830'400 / 4) // unknown divisor
 	MCFG_DEVICE_PROGRAM_MAP(mem_map)
 	MCFG_DEVICE_IO_MAP(io_map)
 
@@ -179,11 +302,13 @@ MACHINE_CONFIG_START(icebox_state::icebox)
 	m_brg->ft_handler().set(m_uart1, FUNC(i8251_device::write_txc));
 	m_brg->ft_handler().append(m_uart1, FUNC(i8251_device::write_rxc));
 
-//	MCFG_DEVICE_ADD("fdc", FD1771, 4_MHz_XTAL / 2)
+	MCFG_DEVICE_ADD(m_fdc, FD1771, 4_MHz_XTAL / 2)
-//	MCFG_FLOPPY_DRIVE_ADD("fdc:0", floppies, "flop", floppy_image_device::default_floppy_formats)
+	MCFG_WD_FDC_INTRQ_CALLBACK(WRITELINE(*this, icebox_state, intrq_w))
-//	MCFG_FLOPPY_DRIVE_SOUND(true)
+	MCFG_WD_FDC_DRQ_CALLBACK(WRITELINE(*this, icebox_state, drq_w))
-//	MCFG_FLOPPY_DRIVE_ADD("fdc:1", floppies, "flop", floppy_image_device::default_floppy_formats)
+	MCFG_FLOPPY_DRIVE_ADD(m_floppy0, floppies, "flop", floppy_image_device::default_floppy_formats)
-//	MCFG_FLOPPY_DRIVE_SOUND(true)
+	MCFG_FLOPPY_DRIVE_SOUND(true)
+	MCFG_FLOPPY_DRIVE_ADD(m_floppy1, floppies, "flop", floppy_image_device::default_floppy_formats)
+	MCFG_FLOPPY_DRIVE_SOUND(true)
 MACHINE_CONFIG_END
 
 /* ROM definition */