saitek_osa: preliminary hook up PW pin

src/devices/bus/saitek_osa/expansion.cpp

@@ -116,6 +116,16 @@ void saitekosa_expansion_device::ack_w(int state)
 	m_ack = state;
 }
 
+void saitekosa_expansion_device::pw_w(int state)
+{
+	state = (state) ? 1 : 0;
+
+	if (m_module)
+		m_module->pw_w(state);
+
+	m_pw = state;
+}
+
 u32 saitekosa_expansion_device::screen_update(screen_device &screen, bitmap_rgb32 &bitmap, const rectangle &cliprect)
 {
 	return (m_module) ? m_module->screen_update(screen, bitmap, cliprect) : UPDATE_HAS_NOT_CHANGED;

src/devices/bus/saitek_osa/expansion.h

@@ -68,12 +68,14 @@ public:
 	u8 data_state() { return m_data; }
 	int nmi_state() { return m_nmi; }
 	int ack_state() { return m_ack; }
+	int pw_state() { return m_pw; }
 
 	// called from host
 	u8 data_r();
 	void data_w(u8 data);
 	void nmi_w(int state);
 	void ack_w(int state);
+	void pw_w(int state);
 
 protected:
 	// device-level overrides
@@ -90,6 +92,7 @@ private:
 	u8 m_data = 0;
 	int m_nmi = 0;
 	int m_ack = 0;
+	int m_pw = 0;
 
 	device_saitekosa_expansion_interface *m_module;
 };
@@ -106,6 +109,7 @@ public:
 	virtual void data_w(u8 data) { }
 	virtual void nmi_w(int state) { }
 	virtual void ack_w(int state) { }
+	virtual void pw_w(int state) { }
 
 	virtual u32 screen_update(screen_device &screen, bitmap_rgb32 &bitmap, const rectangle &cliprect) { return UPDATE_HAS_NOT_CHANGED; }
 

src/devices/bus/saitek_osa/maestro.cpp

@@ -339,7 +339,7 @@ u32 saitekosa_analyst_device::screen_update(screen_device &screen, bitmap_rgb32
 		const u8 *src = render + 16 * ((i & 7) + BIT(i, 3) * 40);
 		for (int y = 0; y < 8; y++)
 			for (int x = 0; x < 5; x++)
-				bitmap.pix(y + 4, i * 6 + x + 2) = BIT(src[y], 4 - x) ? 0x282828 : 0xe8e8e8;
+				bitmap.pix(y + 4, i * 6 + x + 2) = (BIT(src[y], 4 - x) && m_expansion->pw_state()) ? 0x282828 : 0xe8e8e8;
 	}
 
 	return 0;

src/mame/drivers/saitek_leonardo.cpp

@@ -43,9 +43,9 @@ Expansion modules released:
 
 TODO:
 - OSA module comms is not completely understood
-- OSA PC link (probably uses MCU serial interface)
-- add power-off
+- OSA PC link, uses MCU serial interface
 - add nvram (MCU port $14?)
+- add power-off, not useful with missing nvram support
 
 ******************************************************************************/
 
@@ -225,7 +225,8 @@ void leo_state::p5_w(u8 data)
 	m_led_data[0] = (m_led_data[0] & 3) | (~data >> 4 & 0xc);
 	update_display();
 
-	// d0: power-off
+	// d0: power-off on falling edge
+	m_expansion->pw_w(data & 1);
 }
 
 u8 leo_state::p6_r()

src/mame/drivers/saitek_renaissance.cpp

@@ -245,6 +245,9 @@ void ren_state::p5_w(u8 data)
 	// d5: expansion ACK-P
 	m_expansion->ack_w(BIT(data, 5));
 
+	// d0: power-off on falling edge
+	m_expansion->pw_w(data & 1);
+
 	// other: ?
 }