replaced read netin/dtr1/cts2 callbacks in ZX8302 with write handlers, which allows multiple chips to be connected together without using glue methods. [smf]

src/mess/drivers/ql.c

@@ -783,10 +783,7 @@ static ZX8302_INTERFACE( ql_zx8302_intf )
 	DEVCB_DRIVER_LINE_MEMBER(ql_state, ql_comdata_w),
 	DEVCB_NULL, // TXD1
 	DEVCB_DEVICE_LINE_MEMBER(RS232_B_TAG, serial_port_device, tx),
-	DEVCB_NULL, // DTR1
-	DEVCB_DEVICE_LINE_MEMBER(RS232_B_TAG, rs232_port_device, cts_r),
 	DEVCB_NULL, // NETOUT
-	DEVCB_NULL, // NETIN
 	DEVCB_DRIVER_LINE_MEMBER(ql_state, zx8302_mdselck_w),
 	DEVCB_DEVICE_LINE_MEMBER(MDV_1, microdrive_image_device, comms_in_w),
 	DEVCB_DRIVER_LINE_MEMBER(ql_state, zx8302_mdrdw_w),
@@ -1008,6 +1005,7 @@ static MACHINE_CONFIG_START( ql, ql_state )
 	MCFG_MICRODRIVE_ADD(MDV_2, mdv2_config)
 	MCFG_RS232_PORT_ADD(RS232_A_TAG, default_rs232_devices, NULL) // wired as DCE
 	MCFG_RS232_PORT_ADD(RS232_B_TAG, default_rs232_devices, NULL) // wired as DTE
+	MCFG_RS232_OUT_CTS_HANDLER(DEVWRITELINE(ZX8302_TAG, zx8302_device, write_cts2))
 
 	// cartridge
 	MCFG_CARTSLOT_ADD("cart")

src/mess/machine/zx8302.c

@@ -67,10 +67,7 @@ void zx8302_device::device_config_complete()
 		memset(&out_comdata_cb, 0, sizeof(out_comdata_cb));
 		memset(&out_txd1_cb, 0, sizeof(out_txd1_cb));
 		memset(&out_txd2_cb, 0, sizeof(out_txd2_cb));
-		memset(&in_dtr1_cb, 0, sizeof(in_dtr1_cb));
-		memset(&in_cts2_cb, 0, sizeof(in_cts2_cb));
 		memset(&out_netout_cb, 0, sizeof(out_netout_cb));
-		memset(&in_netin_cb, 0, sizeof(in_netin_cb));
 		memset(&out_mdselck_cb, 0, sizeof(out_mdselck_cb));
 		memset(&out_mdseld_cb, 0, sizeof(out_mdseld_cb));
 		memset(&out_mdrdw_cb, 0, sizeof(out_mdrdw_cb));
@@ -175,6 +172,8 @@ inline void zx8302_device::transmit_ipc_data()
 zx8302_device::zx8302_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
 	: device_t(mconfig, ZX8302, "Sinclair ZX8302", tag, owner, clock, "zx8302", __FILE__),
 		device_serial_interface(mconfig, *this),
+		m_dtr1(0),
+		m_cts2(0),
 		m_idr(1),
 		m_irq(0),
 		m_ctr(time(NULL) + RTC_BASE_ADJUST),
@@ -202,10 +201,7 @@ void zx8302_device::device_start()
 	m_out_comdata_func.resolve(out_comdata_cb, *this);
 	m_out_txd1_func.resolve(out_txd1_cb, *this);
 	m_out_txd2_func.resolve(out_txd2_cb, *this);
-	m_in_dtr1_func.resolve(in_dtr1_cb, *this);
-	m_in_cts2_func.resolve(in_cts2_cb, *this);
 	m_out_netout_func.resolve(out_netout_cb, *this);
-	m_in_netin_func.resolve(in_netin_cb, *this);
 	m_out_mdselck_func.resolve(out_mdselck_cb, *this);
 	m_out_mdseld_func.resolve(out_mdseld_cb, *this);
 	m_out_mdrdw_func.resolve(out_mdrdw_cb, *this);
@@ -225,6 +221,8 @@ void zx8302_device::device_start()
 	m_gap_timer->adjust(attotime::zero, 0, attotime::from_msec(31));
 
 	// register for state saving
+	save_item(NAME(m_dtr1));
+	save_item(NAME(m_cts2));
 	save_item(NAME(m_idr));
 	save_item(NAME(m_tcr));
 	save_item(NAME(m_tdr));
@@ -326,7 +324,7 @@ void zx8302_device::rcv_callback()
 	switch (m_tcr & MODE_MASK)
 	{
 	case MODE_NET:
-		receive_register_update_bit(m_in_netin_func());
+		receive_register_update_bit(get_in_data_bit());
 		break;
 	}
 }
@@ -457,10 +455,10 @@ READ8_MEMBER( zx8302_device::status_r )
 	// TODO microdrive GAP
 
 	// data terminal ready
-	data |= m_in_dtr1_func() << 4;
+	data |= m_dtr1 << 4;
 
 	// clear to send
-	data |= m_in_cts2_func() << 5;
+	data |= m_cts2 << 5;
 
 	// IPC busy
 	data |= m_ipc_busy << 6;
@@ -634,3 +632,25 @@ WRITE_LINE_MEMBER( zx8302_device::extint_w )
 		trigger_interrupt(INT_EXTERNAL);
 	}
 }
+
+WRITE_LINE_MEMBER( zx8302_device::write_netin )
+{
+	if (state)
+	{
+		input_callback(m_input_state | RX);
+	}
+	else
+	{
+		input_callback(m_input_state & ~RX);
+	}
+}
+
+WRITE_LINE_MEMBER( zx8302_device::write_dtr1 )
+{
+	m_dtr1 = state;
+}
+
+WRITE_LINE_MEMBER( zx8302_device::write_cts2 )
+{
+	m_cts2 = state;
+}

src/mess/machine/zx8302.h

@@ -77,10 +77,7 @@ struct zx8302_interface
 	devcb_write_line    out_comdata_cb;
 	devcb_write_line    out_txd1_cb;
 	devcb_write_line    out_txd2_cb;
-	devcb_read_line     in_dtr1_cb;
-	devcb_read_line     in_cts2_cb;
 	devcb_write_line    out_netout_cb;
-	devcb_read_line     in_netin_cb;
 
 	// microdrive
 	devcb_write_line    out_mdselck_cb;
@@ -118,6 +115,10 @@ public:
 	DECLARE_WRITE_LINE_MEMBER( comdata_w );
 	DECLARE_WRITE_LINE_MEMBER( extint_w );
 
+	DECLARE_WRITE_LINE_MEMBER( write_netin );
+	DECLARE_WRITE_LINE_MEMBER( write_dtr1 );
+	DECLARE_WRITE_LINE_MEMBER( write_cts2 );
+
 protected:
 	// device-level overrides
 	virtual void device_start();
@@ -194,10 +195,7 @@ private:
 	devcb_resolved_write_line   m_out_comdata_func;
 	devcb_resolved_write_line   m_out_txd1_func;
 	devcb_resolved_write_line   m_out_txd2_func;
-	devcb_resolved_read_line    m_in_dtr1_func;
-	devcb_resolved_read_line    m_in_cts2_func;
 	devcb_resolved_write_line   m_out_netout_func;
-	devcb_resolved_read_line    m_in_netin_func;
 
 	devcb_resolved_write_line   m_out_mdselck_func;
 	devcb_resolved_write_line   m_out_mdseld_func;
@@ -208,6 +206,9 @@ private:
 	devcb_resolved_write_line   m_out_raw2_func;
 	devcb_resolved_read_line    m_in_raw2_func;
 
+	int m_dtr1;
+	int m_cts2;
+
 	// registers
 	UINT8 m_idr;                    // IPC data register
 	UINT8 m_tcr;                    // transfer control register