imds2: printer output completed, seems OK

src/mess/drivers/imds2.c

@@ -35,7 +35,7 @@
 //
 // This board acts as a controller for all I/O of the system.
 // It is structured as if it were 2 boards in one:
-// One part (around 8080) controls Keyboard, CRT & floppy, the other part (around PIO 8741) controls all parallel I/Os
+// One part (around 8080) controls Keyboard, CRT & floppy, the other part (around PIO 8041A) controls all parallel I/Os
 // (Line printer, Paper tape puncher, Paper tape reader, I/O to PROM programmer).
 // Both parts are interfaced to IPC through a bidirectional 8-bit bus.
 // IOC is composed of these parts:
@@ -51,7 +51,7 @@
 // A20 8275     CRT controller
 // A19 2708     Character generator ROM
 // LS1          3.3 kHz beeper
-//*A72 8741-4   CPU @ 6 MHz (PIO: parallel I/O)
+// A72 8041A    CPU @ 6 MHz (PIO: parallel I/O)
 //
 // **********
 // Keyboard controller
@@ -63,8 +63,6 @@
 // ICs that are not emulated yet are marked with "*"
 //
 // TODO:
-// - Emulate PIO. No known dumps of its ROM are available, though.
-// - Emulate line printer output on PIO
 // - Emulate serial channels on IPC
 // - Emulate PIT on IPC
 // - Adjust speed of processors. Wait states are not accounted for yet.
@@ -86,8 +84,6 @@
 // should be mounted and the system reset. After a few seconds the ISIS-II
 // prompt should appear. A command that could be tried is "DIR" that lists
 // the content of floppy disk.
-// Please note that the message "FAILURE -- PIO NOT RESPONDING" is normal
-// as the support for PIO isn't implemented yet
 
 #include "includes/imds2.h"
 
@@ -174,6 +170,7 @@ imds2_state::imds2_state(const machine_config &mconfig, device_type type, const
 	m_palette(*this , "palette"),
 	m_gfxdecode(*this, "gfxdecode"),
 	m_floppy0(*this , FLOPPY_0),
+	m_centronics(*this , "centronics"),
 	m_io_key0(*this , "KEY0"),
 	m_io_key1(*this , "KEY1"),
 	m_io_key2(*this , "KEY2"),
@@ -182,7 +179,8 @@ imds2_state::imds2_state(const machine_config &mconfig, device_type type, const
 	m_io_key5(*this , "KEY5"),
 	m_io_key6(*this , "KEY6"),
 	m_io_key7(*this , "KEY7"),
-	m_ioc_options(*this , "IOC_OPTS")
+	m_ioc_options(*this , "IOC_OPTS"),
+	m_device_status_byte(0xff)
 {
 }
 
@@ -439,8 +437,13 @@ WRITE8_MEMBER(imds2_state::imds2_ioc_mem_w)
 
 READ8_MEMBER(imds2_state::imds2_pio_port_p1_r)
 {
-        // TODO
+	// If STATUS ENABLE/ == 0 return inverted device status byte, else return 0xff
-        return 0;
+	// STATUS ENABLE/ == 0 when P23-P20 == 12 & P24 == 0 & P25 = 1 & P26 = 1
+	if ((m_pio_port2 & 0x7f) == 0x6c) {
+		return ~m_device_status_byte;
+	} else {
+	return 0xff;
+}
 }
 
 WRITE8_MEMBER(imds2_state::imds2_pio_port_p1_w)
@@ -462,6 +465,34 @@ WRITE8_MEMBER(imds2_state::imds2_pio_port_p2_w)
 	m_ipclocpic->ir5_w(BIT(data , 7));
 }
 
+WRITE_LINE_MEMBER(imds2_state::imds2_pio_lpt_ack_w)
+{
+	if (state) {
+		m_device_status_byte |= 0x20;
+	} else {
+		m_device_status_byte &= ~0x20;
+	}
+}
+
+WRITE_LINE_MEMBER(imds2_state::imds2_pio_lpt_busy_w)
+{
+	// Busy is active high in centronics_device whereas it's active low in MDS
+	if (!state) {
+		m_device_status_byte |= 0x10;
+	} else {
+		m_device_status_byte &= ~0x10;
+	}
+}
+
+WRITE_LINE_MEMBER(imds2_state::imds2_pio_lpt_select_w)
+{
+	if (state) {
+		m_device_status_byte |= 0x40;
+	} else {
+		m_device_status_byte &= ~0x40;
+	}
+}
+
 I8275_DRAW_CHARACTER_MEMBER(imds2_state::crtc_display_pixels)
 {
 	unsigned i;
@@ -574,7 +605,24 @@ void imds2_state::imds2_update_beeper(void)
 
 void imds2_state::imds2_update_printer(void)
 {
-        // TODO
+	// Data to printer is ~P1 when STATUS ENABLE/==1, else 0xff (assuming pull-ups on printer)
+	UINT8 printer_data;
+	if ((m_pio_port2 & 0x7f) == 0x6c) {
+		printer_data = 0xff;
+	} else {
+		printer_data = ~m_pio_port1;
+	}
+	m_centronics->write_data0(BIT(printer_data , 0));
+	m_centronics->write_data1(BIT(printer_data , 1));
+	m_centronics->write_data2(BIT(printer_data , 2));
+	m_centronics->write_data3(BIT(printer_data , 3));
+	m_centronics->write_data4(BIT(printer_data , 4));
+	m_centronics->write_data5(BIT(printer_data , 5));
+	m_centronics->write_data6(BIT(printer_data , 6));
+	m_centronics->write_data7(BIT(printer_data , 7));
+
+	// LPT DATA STROBE/ == 0 when P23-P20 == 9 & P24 == 0
+	m_centronics->write_strobe((m_pio_port2 & 0x1f) != 0x09);
 }
 
 static INPUT_PORTS_START(imds2)
@@ -773,6 +821,11 @@ static MACHINE_CONFIG_START(imds2 , imds2_state)
 		MCFG_CPU_ADD("kbcpu", I8741, XTAL_3_579545MHz)         /* 3.579545 MHz */
 		MCFG_CPU_IO_MAP(kb_io_map)
 		MCFG_QUANTUM_TIME(attotime::from_hz(100))
+
+		MCFG_CENTRONICS_ADD("centronics", centronics_devices, "printer")
+		MCFG_CENTRONICS_ACK_HANDLER(WRITELINE(imds2_state , imds2_pio_lpt_ack_w))
+		MCFG_CENTRONICS_BUSY_HANDLER(WRITELINE(imds2_state , imds2_pio_lpt_busy_w))
+		MCFG_CENTRONICS_PERROR_HANDLER(WRITELINE(imds2_state , imds2_pio_lpt_select_w))
 MACHINE_CONFIG_END
 
 ROM_START(imds2)
@@ -789,7 +842,7 @@ ROM_START(imds2)
 
 		// ROM definition of PIO controller (8041A)
 		ROM_REGION(0x400 , "iocpio" , 0)
-                ROM_LOAD("pio_a72.bin" , 0 , 0x400 , CRC(c1eabf25))
+		ROM_LOAD("pio_a72.bin" , 0 , 0x400 , BAD_DUMP CRC(9a446534))
 
 		// ROM definition of keyboard controller (8741)
 		ROM_REGION(0x400 , "kbcpu" , 0)

src/mess/includes/imds2.h

@@ -15,6 +15,7 @@
 #include "machine/pic8259.h"
 #include "machine/i8271.h"
 #include "imagedev/flopdrv.h"
+#include "bus/centronics/ctronics.h"
 
 class imds2_state : public driver_device
 {
@@ -57,6 +58,9 @@ class imds2_state : public driver_device
 	DECLARE_WRITE8_MEMBER(imds2_pio_port_p1_w);
 	DECLARE_READ8_MEMBER(imds2_pio_port_p2_r);
 	DECLARE_WRITE8_MEMBER(imds2_pio_port_p2_w);
+	DECLARE_WRITE_LINE_MEMBER(imds2_pio_lpt_ack_w);
+	DECLARE_WRITE_LINE_MEMBER(imds2_pio_lpt_busy_w);
+	DECLARE_WRITE_LINE_MEMBER(imds2_pio_lpt_select_w);
 
 	I8275_DRAW_CHARACTER_MEMBER(crtc_display_pixels);
 
@@ -80,6 +84,7 @@ class imds2_state : public driver_device
 	required_device<palette_device> m_palette;
 	required_device<gfxdecode_device> m_gfxdecode;
 	required_device<legacy_floppy_image_device> m_floppy0;
+	required_device<centronics_device> m_centronics;
 	required_ioport m_io_key0;
 	required_ioport m_io_key1;
 	required_ioport m_io_key2;
@@ -129,6 +134,9 @@ class imds2_state : public driver_device
 
 	// PIO port 2
 	UINT8 m_pio_port2;
+
+	// PIO device status byte
+	UINT8 m_device_status_byte;
 };
 
 #endif /* _IMDS2_H_ */