diff --git a/.gitignore b/.gitignore
index bb8e3c86..74ad88cc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -96,7 +96,7 @@ Tools/unix/zx/zx
 !Source/ZRC/*.bin
 !Source/ZZR/*.bin
 !Source/ZZR/*.hex
-!Tools/cpm/bin/*
+!Tools/cpm/**
 !Tools/unix/zx/*
 !Tools/zx/*
 
diff --git a/Source/Apps/Tune/tune.asm b/Source/Apps/Tune/tune.asm
index 4659f556..27b07723 100644
--- a/Source/Apps/Tune/tune.asm
+++ b/Source/Apps/Tune/tune.asm
@@ -44,6 +44,7 @@
 ;   2020-09-03 [E?B] Add support for Ed Brindley YM/AY Sound Card v6
 ;   2021-08-13 [WBW] Add support for LiNC Z50 Sound Card
 ;   2021-08-17 [WBW] When playing via HBIOS, call BF_SNDRESET at end
+;   2022-03-20 [DDW] Add support for MBC PSG module
 ;_______________________________________________________________________________
 ;
 ; ToDo:
@@ -653,7 +654,7 @@ TMP		.DB	0	; work around use of undocumented Z80
 HBIOSMD		.DB	0	; NON-ZERO IF USING HBIOS SOUND DRIVER, ZERO OTHERWISE
 OCTAVEADJ	.DB	0	; AMOUNT TO ADJUST OCTAVE UP OR DOWN
 
-MSGBAN		.DB	"Tune Player for RomWBW v3.4, 17-Aug-2021",0
+MSGBAN		.DB	"Tune Player for RomWBW v3.5, 20-Mar-2022",0
 MSGUSE		.DB	"Copyright (C) 2021, Wayne Warthen, GNU GPL v3",13,10
 		.DB	"PTxPlayer Copyright (C) 2004-2007 S.V.Bulba",13,10
 		.DB	"MYMPlay by Marq/Lieves!Tuore",13,10,13,10
diff --git a/Source/HBIOS/cen.asm b/Source/HBIOS/cen.asm
index 4cceeca1..834fa8c6 100644
--- a/Source/HBIOS/cen.asm
+++ b/Source/HBIOS/cen.asm
@@ -134,7 +134,7 @@ CEN_IN:
 ; BYTE OUTPUT
 ;
 CEN_OUT:
-	CALL	CEN_OST			; READY FOR CHAR?
+	CALL	CEN_OST			; READY TO SEND?
 	JR	Z,CEN_OUT		; LOOP IF NOT
 	; *** ADD CODE TO OUTPUT BYTE ***
 	XOR	A			; SIGNAL SUCCESS
@@ -166,9 +166,15 @@ CEN_INITDEV:
 ; PREINIT ABOVE.  PREINIT IS NOT ALLOWED TO ENABLE INTS!
 ;
 CEN_INITDEVX:
-;
-	; *** ADD CODE TO INITIALIZE DEVICE ***
-;
+	; *** NOT SURE THIS IS RIGHT ***
+	LD	A,(IY+3)
+	LD	C,A			; PORT 0 (DATA)
+	XOR	A			; CLEAR ACCUM
+	OUT	(C),A			; SEND IT
+	INC	C			; BUMP TO
+	INC	C			; ... PORT 2
+	LD	A,%11000000		; RESET, LEDS OFF
+	OUT	(C),A			; SEND IT
 	XOR	A			; SIGNAL SUCCESS
 	RET				; RETURN
 ;
@@ -195,6 +201,7 @@ CEN_DEVICE:
 ;
 CEN_DETECT:
 	LD	A,(IY+3)		; BASE PORT ADDRESS
+	ADD	A,2			; USE PORT 2 FOR DETECT
 	LD	C,A			; PUT IN C FOR I/O
 	CALL	CEN_DETECT2		; CHECK IT
 	JR	Z,CEN_DETECT1		; FOUND IT, RECORD IT
@@ -208,9 +215,18 @@ CEN_DETECT1:
 ;
 CEN_DETECT2:
 	; LOOK FOR CEN AT PORT ADDRESS IN C
-	; *** ADD CODE TO DETECT DEVICE ***
-	OR	$FF			; TEMP SET TO NOT PRESENT
-	RET				; RETURN RESULT, Z = CHIP FOUND
+	XOR	A			; DEFAULT VALUE
+	OUT	(C),A			; SEND IT
+	IN	A,(C)			; READ IT
+	AND	%11000000		; ISOLATE STATUS BITS
+	CP	%00000000		; CORRECT VALUE?
+	RET	NZ			; IF NOT, RETURN
+	LD	A,%11000000		; STATUS BITS ON (LEDS OFF)
+	OUT	(C),A			; SEND IT
+	IN	A,(C)			; READ IT
+	AND	%11000000		; ISOLATE STATUS BITS
+	CP	%11000000		; CORRECT VALUE?
+	RET				; RETURN (ZF SET CORRECTLY)
 ;
 ;
 ;
@@ -249,10 +265,10 @@ CEN_PRTCFG:
 ;
 CEN_TYPE_MAP:
 		.DW	CEN_STR_NONE
-		.DW	CEN_STR_CEN
+		.DW	CEN_STR_MBC
 ;
 CEN_STR_NONE	.DB	"<NOT PRESENT>$"
-CEN_STR_CEN	.DB	"MBC$"
+CEN_STR_MBC	.DB	"MBC$"
 ;
 ; WORKING VARIABLES
 ;
diff --git a/Source/HBIOS/cfg_mbc.asm b/Source/HBIOS/cfg_mbc.asm
index d025d429..0158e09f 100644
--- a/Source/HBIOS/cfg_mbc.asm
+++ b/Source/HBIOS/cfg_mbc.asm
@@ -243,9 +243,9 @@ AUDIOTRACE	.EQU	FALSE		; ENABLE TRACING TO CONSOLE OF SOUND DRIVER
 SN7CLK		.EQU	CPUOSC / 4	; DEFAULT TO CPUOSC / 4
 SNMODE		.EQU	SNMODE_NONE	; DRIVER MODE: SNMODE_[NONE|RC2014|VGM]
 ;
-AY38910ENABLE	.EQU	FALSE		; AY: AY-3-8910 / YM2149 SOUND DRIVER
-AY_CLK		.EQU	CPUOSC / 4	; DEFAULT TO CPUOSC / 4
-AYMODE		.EQU	AYMODE_NONE	; AY: DRIVER MODE: AYMODE_[SCG|N8|RCZ80|RCZ180|MSX|LINC|MBC]
+AY38910ENABLE	.EQU	TRUE		; AY: AY-3-8910 / YM2149 SOUND DRIVER
+AY_CLK		.EQU	3579545 / 2	; DEFAULT TO CPUOSC / 4
+AYMODE		.EQU	AYMODE_MBC	; AY: DRIVER MODE: AYMODE_[SCG|N8|RCZ80|RCZ180|MSX|LINC|MBC]
 ;
 SPKENABLE	.EQU	TRUE		; SPK: ENABLE RTC LATCH IOBIT SOUND DRIVER (SPK.ASM)
 ;
diff --git a/Source/ver.inc b/Source/ver.inc
index 052a21f4..c8a6de03 100644
--- a/Source/ver.inc
+++ b/Source/ver.inc
@@ -2,4 +2,4 @@
 #DEFINE	RMN	1
 #DEFINE	RUP	1
 #DEFINE	RTP	0
-#DEFINE BIOSVER	"3.1.1-pre.164"
+#DEFINE BIOSVER	"3.1.1-pre.165"
diff --git a/Source/ver.lib b/Source/ver.lib
index bc0ff5e9..92cf12c1 100644
--- a/Source/ver.lib
+++ b/Source/ver.lib
@@ -3,5 +3,5 @@ rmn	equ	1
 rup	equ	1
 rtp	equ	0
 biosver	macro
-	db	"3.1.1-pre.164"
+	db	"3.1.1-pre.165"
 	endm
diff --git a/Tools/cpm/bin80/ASM.COM b/Tools/cpm/bin80/ASM.COM
new file mode 100644
index 00000000..a63e5aec
Binary files /dev/null and b/Tools/cpm/bin80/ASM.COM differ