diff --git a/src/emu/video/cdp1869.c b/src/emu/video/cdp1869.c
index 3be7abf678d..a14344771ee 100644
--- a/src/emu/video/cdp1869.c
+++ b/src/emu/video/cdp1869.c
@@ -2,8 +2,8 @@
 #include "sndintrf.h"
 #include "streams.h"
 #include "cpu/cdp1802/cdp1802.h"
-#include "video/cdp1869.h"
 #include "sound/cdp1869.h"
+#include "video/cdp1869.h"
 
 /*
 
@@ -569,7 +569,10 @@ WRITE8_DEVICE_HANDLER( cdp1869_pageram_w )
 		pma = offset;
 	}
 
-	cdp1869->intf->page_ram_w(device, pma, data);
+	if (cdp1869->intf->page_ram_w)
+	{
+		cdp1869->intf->page_ram_w(device, pma, data);
+	}
 }
 
 /* Character RAM Access */
@@ -610,7 +613,10 @@ WRITE8_DEVICE_HANDLER( cdp1869_charram_w )
 			cma &= 0x07;
 		}
 
-		cdp1869->intf->char_ram_w(device, pma, cma, data);
+		if (cdp1869->intf->char_ram_w)
+		{
+			cdp1869->intf->char_ram_w(device, pma, cma, data);
+		}
 	}
 }
 
@@ -776,10 +782,8 @@ static DEVICE_START( cdp1869 )
 	cdp1869->intf = device->static_config;
 
 	assert(cdp1869->intf->page_ram_r != NULL);
-	assert(cdp1869->intf->page_ram_w != NULL);
 	assert(cdp1869->intf->pcb_r != NULL);
 	assert(cdp1869->intf->char_ram_r != NULL);
-	assert(cdp1869->intf->char_ram_w != NULL);
 
 	// set initial values
 
diff --git a/src/emu/video/cdp1869.h b/src/emu/video/cdp1869.h
index e5bb914abe2..f69cba501ce 100644
--- a/src/emu/video/cdp1869.h
+++ b/src/emu/video/cdp1869.h
@@ -132,6 +132,7 @@ struct _cdp1869_interface
 	/* if specified, this gets called for every change of the predisplay pin (CDP1870/76 pin 1) */
 	cdp1869_on_prd_changed_func		on_prd_changed;
 };
+#define CDP1869_INTERFACE(name) const cdp1869_interface (name) =
 
 /* device interface */
 DEVICE_GET_INFO( cdp1869_video );
@@ -139,7 +140,7 @@ DEVICE_GET_INFO( cdp1869_video );
 /* palette initialization */
 PALETTE_INIT( cdp1869 );
 
-/* io port access */
+/* register access */
 WRITE8_DEVICE_HANDLER( cdp1869_out3_w );
 WRITE8_DEVICE_HANDLER( cdp1869_out4_w );
 WRITE8_DEVICE_HANDLER( cdp1869_out5_w );
@@ -154,7 +155,7 @@ WRITE8_DEVICE_HANDLER ( cdp1869_charram_w );
 READ8_DEVICE_HANDLER ( cdp1869_pageram_r );
 WRITE8_DEVICE_HANDLER ( cdp1869_pageram_w );
 
-/* updates the screen */
+/* screen update */
 void cdp1869_update(const device_config *device, bitmap_t *bitmap, const rectangle *cliprect);
 
 #endif
diff --git a/src/mame/video/cidelsa.c b/src/mame/video/cidelsa.c
index c4b9b0d38db..b97464e16ea 100644
--- a/src/mame/video/cidelsa.c
+++ b/src/mame/video/cidelsa.c
@@ -182,7 +182,7 @@ static const cdp1869_interface altair_cdp1869_intf =
 	cidelsa_prd_changed,
 };
 
-static const cdp1869_interface draco_cdp1869_intf =
+static CDP1869_INTERFACE( draco_cdp1869_intf )
 {
 	SCREEN_TAG,
 	DRACO_CHR2,