diff --git a/src/mame/drivers/nova2001.c b/src/mame/drivers/nova2001.c
index 58c8141a6e7..a3192c7dd7f 100644
--- a/src/mame/drivers/nova2001.c
+++ b/src/mame/drivers/nova2001.c
@@ -194,10 +194,10 @@ ADDRESS_MAP_END
 static ADDRESS_MAP_START( ninjakun_cpu1_map, ADDRESS_SPACE_PROGRAM, 8 )
 	AM_RANGE(0x0000, 0x1fff) AM_ROM
 	AM_RANGE(0x2000, 0x7fff) AM_ROM
-	AM_RANGE(0x8000, 0x8000) AM_DEVWRITE("ay1", ay8910_address_w)
-	AM_RANGE(0x8001, 0x8001) AM_DEVREADWRITE("ay1", ay8910_r, ay8910_data_w)
-	AM_RANGE(0x8002, 0x8002) AM_DEVWRITE("ay2", ay8910_address_w)
-	AM_RANGE(0x8003, 0x8003) AM_DEVREADWRITE("ay2", ay8910_r, ay8910_data_w)
+	AM_RANGE(0x8000, 0x8001) AM_DEVWRITE("ay1", ay8910_address_data_w)
+	AM_RANGE(0x8001, 0x8001) AM_DEVREAD("ay1", ay8910_r)
+	AM_RANGE(0x8002, 0x8003) AM_DEVWRITE("ay2", ay8910_address_data_w)
+	AM_RANGE(0x8003, 0x8003) AM_DEVREAD("ay2", ay8910_r)
 	AM_RANGE(0xa000, 0xa000) AM_READ_PORT("IN0")
 	AM_RANGE(0xa001, 0xa001) AM_READ_PORT("IN1")
 	AM_RANGE(0xa002, 0xa002) AM_READ_PORT("IN2") AM_WRITE(ninjakun_cpu1_io_A002_w)
@@ -213,10 +213,10 @@ ADDRESS_MAP_END
 static ADDRESS_MAP_START( ninjakun_cpu2_map, ADDRESS_SPACE_PROGRAM, 8 )
 	AM_RANGE(0x0000, 0x1fff) AM_ROM
 	AM_RANGE(0x2000, 0x7fff) AM_ROM AM_REGION("maincpu", 0x2000)
-	AM_RANGE(0x8000, 0x8000) AM_DEVWRITE("ay1", ay8910_address_w)
-	AM_RANGE(0x8001, 0x8001) AM_DEVREADWRITE("ay1", ay8910_r, ay8910_data_w)
-	AM_RANGE(0x8002, 0x8002) AM_DEVWRITE("ay2", ay8910_address_w)
-	AM_RANGE(0x8003, 0x8003) AM_DEVREADWRITE("ay2", ay8910_r, ay8910_data_w)
+	AM_RANGE(0x8000, 0x8001) AM_DEVWRITE("ay1", ay8910_address_data_w)
+	AM_RANGE(0x8001, 0x8001) AM_DEVREAD("ay1", ay8910_r)
+	AM_RANGE(0x8002, 0x8003) AM_DEVWRITE("ay2", ay8910_address_data_w)
+	AM_RANGE(0x8003, 0x8003) AM_DEVREAD("ay2", ay8910_r)
 	AM_RANGE(0xa000, 0xa000) AM_READ_PORT("IN0")
 	AM_RANGE(0xa001, 0xa001) AM_READ_PORT("IN1")
 	AM_RANGE(0xa002, 0xa002) AM_READ_PORT("IN2") AM_WRITE(ninjakun_cpu2_io_A002_w)
@@ -234,10 +234,10 @@ static ADDRESS_MAP_START( pkunwar_map, ADDRESS_SPACE_PROGRAM, 8 )
 	AM_RANGE(0x0000, 0x7fff) AM_ROM
 	AM_RANGE(0x8000, 0x87ff) AM_RAM AM_BASE(&spriteram)
 	AM_RANGE(0x8800, 0x8fff) AM_RAM_WRITE(nova2001_bg_videoram_w) AM_BASE(&nova2001_bg_videoram)
-	AM_RANGE(0xa000, 0xa000) AM_DEVWRITE("ay1", ay8910_address_w)
-	AM_RANGE(0xa001, 0xa001) AM_DEVREADWRITE("ay1", ay8910_r, ay8910_data_w)
-	AM_RANGE(0xa002, 0xa002) AM_DEVWRITE("ay2", ay8910_address_w)
-	AM_RANGE(0xa003, 0xa003) AM_DEVREADWRITE("ay2", ay8910_r, ay8910_data_w)
+	AM_RANGE(0xa000, 0xa001) AM_DEVWRITE("ay1", ay8910_address_data_w)
+	AM_RANGE(0xa001, 0xa001) AM_DEVREAD("ay1", ay8910_r)
+	AM_RANGE(0xa002, 0xa003) AM_DEVWRITE("ay2", ay8910_address_data_w)
+	AM_RANGE(0xa003, 0xa003) AM_DEVREAD("ay2", ay8910_r)
 	AM_RANGE(0xc000, 0xc7ff) AM_RAM
 	AM_RANGE(0xe000, 0xffff) AM_ROM
 ADDRESS_MAP_END
@@ -256,20 +256,20 @@ static ADDRESS_MAP_START( raiders5_cpu1_map, ADDRESS_SPACE_PROGRAM, 8 )
 	AM_RANGE(0xa000, 0xa000) AM_WRITE(nova2001_scroll_x_w)
 	AM_RANGE(0xa001, 0xa001) AM_WRITE(nova2001_scroll_y_w)
 	AM_RANGE(0xa002, 0xa002) AM_WRITE(pkunwar_flipscreen_w)
-	AM_RANGE(0xc000, 0xc000) AM_DEVWRITE("ay1", ay8910_address_w)
-	AM_RANGE(0xc001, 0xc001) AM_DEVREADWRITE("ay1", ay8910_r, ay8910_data_w)
-	AM_RANGE(0xc002, 0xc002) AM_DEVWRITE("ay2", ay8910_address_w)
-	AM_RANGE(0xc003, 0xc003) AM_DEVREADWRITE("ay2", ay8910_r, ay8910_data_w)
+	AM_RANGE(0xc000, 0xc001) AM_DEVWRITE("ay1", ay8910_address_data_w)
+	AM_RANGE(0xc001, 0xc001) AM_DEVREAD("ay1", ay8910_r)
+	AM_RANGE(0xc002, 0xc003) AM_DEVWRITE("ay2", ay8910_address_data_w)
+	AM_RANGE(0xc003, 0xc003) AM_DEVREAD("ay2", ay8910_r)
 	AM_RANGE(0xd000, 0xd1ff) AM_RAM_WRITE(ninjakun_paletteram_w) AM_BASE(&paletteram)
 	AM_RANGE(0xe000, 0xe7ff) AM_RAM AM_SHARE(1)
 ADDRESS_MAP_END
 
 static ADDRESS_MAP_START( raiders5_cpu2_map, ADDRESS_SPACE_PROGRAM, 8 )
 	AM_RANGE(0x0000, 0x3fff) AM_ROM
-	AM_RANGE(0x8000, 0x8000) AM_DEVWRITE("ay1", ay8910_address_w)
-	AM_RANGE(0x8001, 0x8001) AM_DEVREADWRITE("ay1", ay8910_r, ay8910_data_w)
-	AM_RANGE(0x8002, 0x8002) AM_DEVWRITE("ay2", ay8910_address_w)
-	AM_RANGE(0x8003, 0x8003) AM_DEVREADWRITE("ay2", ay8910_r, ay8910_data_w)
+	AM_RANGE(0x8000, 0x8001) AM_DEVWRITE("ay1", ay8910_address_data_w)
+	AM_RANGE(0x8001, 0x8001) AM_DEVREAD("ay1", ay8910_r)
+	AM_RANGE(0x8002, 0x8003) AM_DEVWRITE("ay2", ay8910_address_data_w)
+	AM_RANGE(0x8003, 0x8003) AM_DEVREAD("ay2", ay8910_r)
 	AM_RANGE(0x9000, 0x9000) AM_READ(SMH_NOP) /* unknown */
 	AM_RANGE(0xa000, 0xa7ff) AM_RAM AM_SHARE(1)
 	AM_RANGE(0xc000, 0xc000) AM_READ(SMH_NOP) /* unknown */