From 22a0c52af3c8b45f262a2961e2c2e32346e0b9f1 Mon Sep 17 00:00:00 2001
From: Wayne Warthen <wwarthen@gmail.com>
Date: Sun, 20 Aug 2023 12:10:32 -0700
Subject: [PATCH 1/2] Bump Version

---
 Source/ver.inc | 2 +-
 Source/ver.lib | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Source/ver.inc b/Source/ver.inc
index 17fe5ab8..d825e9f1 100644
--- a/Source/ver.inc
+++ b/Source/ver.inc
@@ -2,7 +2,7 @@
 #DEFINE	RMN	3
 #DEFINE	RUP	0
 #DEFINE	RTP	0
-#DEFINE BIOSVER	"3.3.0-dev.42"
+#DEFINE BIOSVER	"3.3.0-dev.43"
 #define rmj	RMJ
 #define rmn	RMN
 #define rup	RUP
diff --git a/Source/ver.lib b/Source/ver.lib
index c8a80e26..d0b3516b 100644
--- a/Source/ver.lib
+++ b/Source/ver.lib
@@ -3,5 +3,5 @@ rmn	equ	3
 rup	equ	0
 rtp	equ	0
 biosver	macro
-	db	"3.3.0-dev.42"
+	db	"3.3.0-dev.43"
 	endm

From d06e1e2a5ce66a89a2b3e60dc960b05895d7a0e7 Mon Sep 17 00:00:00 2001
From: Wayne Warthen <wwarthen@gmail.com>
Date: Sun, 20 Aug 2023 15:03:34 -0700
Subject: [PATCH 2/2] Initial DUO Interrupt Handling

---
 Source/HBIOS/cfg_duo.asm      |  3 +--
 Source/HBIOS/cfg_dyno.asm     |  3 +--
 Source/HBIOS/cfg_master.asm   |  3 +--
 Source/HBIOS/cfg_mbc.asm      |  3 +--
 Source/HBIOS/cfg_mk4.asm      |  3 +--
 Source/HBIOS/cfg_n8.asm       |  3 +--
 Source/HBIOS/cfg_rcz180.asm   |  3 +--
 Source/HBIOS/cfg_rcz280.asm   |  3 +--
 Source/HBIOS/cfg_rcz80.asm    |  3 +--
 Source/HBIOS/cfg_rph.asm      |  3 +--
 Source/HBIOS/cfg_s100.asm     |  3 +--
 Source/HBIOS/cfg_sbc.asm      |  3 +--
 Source/HBIOS/cfg_scz180.asm   |  3 +--
 Source/HBIOS/cfg_z80retro.asm |  3 +--
 Source/HBIOS/cfg_zeta.asm     |  1 -
 Source/HBIOS/cfg_zeta2.asm    |  3 +--
 Source/HBIOS/std.asm          |  8 ++++++++
 Source/HBIOS/uart.asm         | 15 ++++-----------
 18 files changed, 27 insertions(+), 42 deletions(-)

diff --git a/Source/HBIOS/cfg_duo.asm b/Source/HBIOS/cfg_duo.asm
index 79f0ef50..ebf847d5 100644
--- a/Source/HBIOS/cfg_duo.asm
+++ b/Source/HBIOS/cfg_duo.asm
@@ -126,14 +126,13 @@ UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA ONBOARD UART
+UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTDUO		.EQU	TRUE		; UART: AUTO-DETECT DUODYNE UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/cfg_dyno.asm b/Source/HBIOS/cfg_dyno.asm
index 1ea8ffac..0432faf6 100644
--- a/Source/HBIOS/cfg_dyno.asm
+++ b/Source/HBIOS/cfg_dyno.asm
@@ -129,14 +129,13 @@ UARTENABLE	.EQU	FALSE		; UART: ENABLE 8250/16550-LIKE SERIAL DRIVER (UART.ASM)
 UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG | SER_RTS	; UART: LINE CONFIG FOR UART PORTS
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	TRUE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE UART
 ;
 ASCIENABLE	.EQU	TRUE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ASCIINTS	.EQU	TRUE		; ASCI: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
diff --git a/Source/HBIOS/cfg_master.asm b/Source/HBIOS/cfg_master.asm
index b9c97840..77f5f8e8 100644
--- a/Source/HBIOS/cfg_master.asm
+++ b/Source/HBIOS/cfg_master.asm
@@ -165,14 +165,13 @@ UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ASCIINTS	.EQU	TRUE		; ASCI: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
diff --git a/Source/HBIOS/cfg_mbc.asm b/Source/HBIOS/cfg_mbc.asm
index 994c670d..796deba8 100644
--- a/Source/HBIOS/cfg_mbc.asm
+++ b/Source/HBIOS/cfg_mbc.asm
@@ -123,14 +123,13 @@ UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA ONBOARD UART
+UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	TRUE		; UART: AUTO-DETECT DUAL UART
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/cfg_mk4.asm b/Source/HBIOS/cfg_mk4.asm
index 035e1c1c..455e68b3 100644
--- a/Source/HBIOS/cfg_mk4.asm
+++ b/Source/HBIOS/cfg_mk4.asm
@@ -129,14 +129,13 @@ UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	TRUE		; UART: AUTO-DETECT ECB CASSETTE UART
 UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	TRUE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE UART
 ;
 ASCIENABLE	.EQU	TRUE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ASCIINTS	.EQU	TRUE		; ASCI: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
diff --git a/Source/HBIOS/cfg_n8.asm b/Source/HBIOS/cfg_n8.asm
index 22a3e992..abb59c59 100644
--- a/Source/HBIOS/cfg_n8.asm
+++ b/Source/HBIOS/cfg_n8.asm
@@ -131,14 +131,13 @@ UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	TRUE		; UART: AUTO-DETECT ECB CASSETTE UART
 UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	TRUE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE UART
 ;
 ASCIENABLE	.EQU	TRUE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ASCIINTS	.EQU	TRUE		; ASCI: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
diff --git a/Source/HBIOS/cfg_rcz180.asm b/Source/HBIOS/cfg_rcz180.asm
index 1d72aa72..8e62ba34 100644
--- a/Source/HBIOS/cfg_rcz180.asm
+++ b/Source/HBIOS/cfg_rcz180.asm
@@ -135,14 +135,13 @@ UARTENABLE	.EQU	TRUE		; UART: ENABLE 8250/16550-LIKE SERIAL DRIVER (UART.ASM)
 UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG | SER_RTS	; UART: LINE CONFIG FOR UART PORTS
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	TRUE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE UART
 ;
 ASCIENABLE	.EQU	TRUE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ASCIINTS	.EQU	TRUE		; ASCI: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
diff --git a/Source/HBIOS/cfg_rcz280.asm b/Source/HBIOS/cfg_rcz280.asm
index 9f786105..1f75b314 100644
--- a/Source/HBIOS/cfg_rcz280.asm
+++ b/Source/HBIOS/cfg_rcz280.asm
@@ -129,14 +129,13 @@ UARTENABLE	.EQU	TRUE		; UART: ENABLE 8250/16550-LIKE SERIAL DRIVER (UART.ASM)
 UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG | SER_RTS	; UART: LINE CONFIG FOR UART PORTS
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	TRUE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/cfg_rcz80.asm b/Source/HBIOS/cfg_rcz80.asm
index bbab0410..e5b75a1a 100644
--- a/Source/HBIOS/cfg_rcz80.asm
+++ b/Source/HBIOS/cfg_rcz80.asm
@@ -128,14 +128,13 @@ UARTENABLE	.EQU	TRUE		; UART: ENABLE 8250/16550-LIKE SERIAL DRIVER (UART.ASM)
 UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG | SER_RTS	; UART: LINE CONFIG FOR UART PORTS
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	TRUE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/cfg_rph.asm b/Source/HBIOS/cfg_rph.asm
index 37dbc551..61b07a1e 100644
--- a/Source/HBIOS/cfg_rph.asm
+++ b/Source/HBIOS/cfg_rph.asm
@@ -129,14 +129,13 @@ UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE UART
 ;
 ASCIENABLE	.EQU	TRUE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ASCIINTS	.EQU	TRUE		; ASCI: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
diff --git a/Source/HBIOS/cfg_s100.asm b/Source/HBIOS/cfg_s100.asm
index 935b3978..9b61a6be 100644
--- a/Source/HBIOS/cfg_s100.asm
+++ b/Source/HBIOS/cfg_s100.asm
@@ -129,14 +129,13 @@ UARTENABLE	.EQU	TRUE		; UART: ENABLE 8250/16550-LIKE SERIAL DRIVER (UART.ASM)
 UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG | SER_RTS	; UART: LINE CONFIG FOR UART PORTS
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	TRUE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE UART
 ;
 ASCIENABLE	.EQU	TRUE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ASCIINTS	.EQU	TRUE		; ASCI: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
diff --git a/Source/HBIOS/cfg_sbc.asm b/Source/HBIOS/cfg_sbc.asm
index df31b8a2..18fb32c5 100644
--- a/Source/HBIOS/cfg_sbc.asm
+++ b/Source/HBIOS/cfg_sbc.asm
@@ -123,14 +123,13 @@ UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA ONBOARD UART
+UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	TRUE		; UART: AUTO-DETECT ECB CASSETTE UART
 UARTMFP		.EQU	TRUE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	TRUE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/cfg_scz180.asm b/Source/HBIOS/cfg_scz180.asm
index 86d8a3c4..88cd988b 100644
--- a/Source/HBIOS/cfg_scz180.asm
+++ b/Source/HBIOS/cfg_scz180.asm
@@ -129,14 +129,13 @@ UARTENABLE	.EQU	TRUE		; UART: ENABLE 8250/16550-LIKE SERIAL DRIVER (UART.ASM)
 UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG | SER_RTS	; UART: LINE CONFIG FOR UART PORTS
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	TRUE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE UART
 ;
 ASCIENABLE	.EQU	TRUE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ASCIINTS	.EQU	TRUE		; ASCI: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
diff --git a/Source/HBIOS/cfg_z80retro.asm b/Source/HBIOS/cfg_z80retro.asm
index 880cc9fb..d2f32854 100644
--- a/Source/HBIOS/cfg_z80retro.asm
+++ b/Source/HBIOS/cfg_z80retro.asm
@@ -121,14 +121,13 @@ UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA ONBOARD UART
+UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/cfg_zeta.asm b/Source/HBIOS/cfg_zeta.asm
index 921683a2..a65c0dda 100644
--- a/Source/HBIOS/cfg_zeta.asm
+++ b/Source/HBIOS/cfg_zeta.asm
@@ -117,7 +117,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/cfg_zeta2.asm b/Source/HBIOS/cfg_zeta2.asm
index d2dcfc37..cac53563 100644
--- a/Source/HBIOS/cfg_zeta2.asm
+++ b/Source/HBIOS/cfg_zeta2.asm
@@ -121,14 +121,13 @@ UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA ONBOARD UART
+UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/std.asm b/Source/HBIOS/std.asm
index 4de1147b..fbd8b5ff 100644
--- a/Source/HBIOS/std.asm
+++ b/Source/HBIOS/std.asm
@@ -780,6 +780,13 @@ INT_CTC0D	.EQU	15	; ZILOG CTC 0, CHANNEL D
 
   #ELSE
 
+    #IF (PLATFORM == PLT_DUO)
+
+INT_UART0	.EQU	7	; UART 0
+INT_UART1	.EQU	6	; UART 1 ?????
+
+    #ELSE
+
 ; GENERIC Z80
 INT_CTC0A	.EQU	0	; ZILOG CTC 0, CHANNEL A
 INT_CTC0B	.EQU	1	; ZILOG CTC 0, CHANNEL B
@@ -794,6 +801,7 @@ INT_PIO0B	.EQU	10	; ZILOG PIO 0, CHANNEL B
 INT_PIO1A	.EQU	11	; ZILOG PIO 1, CHANNEL A
 INT_PIO1B	.EQU	12	; ZILOG PIO 1, CHANNEL B
 
+      #ENDIF
     #ENDIF
 #ENDIF
 
diff --git a/Source/HBIOS/uart.asm b/Source/HBIOS/uart.asm
index 633f4d6b..5deff4ac 100644
--- a/Source/HBIOS/uart.asm
+++ b/Source/HBIOS/uart.asm
@@ -53,13 +53,16 @@ UART_INTACT		.EQU	7	; INT RCV ACTIVE BIT
 UART_FIFOACT		.EQU	6	; FIFO ACTIVE BIT
 UART_AFCACT		.EQU	5	; AUTO FLOW CONTROL ACTIVE BIT
 ;
+#IF (PLATFORM == PLT_DUO)
+UARTSBASE		.EQU	$58
+#ELSE
 UARTSBASE		.EQU	$68
+#ENDIF
 UARTCBASE		.EQU	$80
 UARTMBASE		.EQU	$18
 UART4BASE		.EQU	$C0
 UARTRBASE		.EQU	$A0
 UARTDBASE		.EQU	$80
-UARTYBASE		.EQU	$58
 ;
 #IF (UARTINTS)
 ;
@@ -1088,16 +1091,6 @@ UART_CFG_MFP:
 	.DW	UARTCFG				; LINE CONFIGURATION
 	.DW	0				; SHOULD NEVER NEED INT HANDLER
 #ENDIF
-#IF (UARTDUO)
-UART_CFG_DUO:
-	; DUODYNE ONBOARD SERIAL PORT
-	.DB	0				; DEVICE NUMBER (UPDATED DURING INIT)
-	.DB	0				; UART TYPE
-	.DB	UARTYBASE			; IO PORT BASE (RBR, THR)
-	.DB	UARTYBASE + UART_LSR		; LINE STATUS PORT (LSR)
-	.DW	UARTCFG				; LINE CONFIGURATION
-	.DW	0				; POINTER TO RCV BUFFER STRUCT
-#ENDIF
 ;
 UART_CNT	.EQU	($ - UART_CFG) / 8
 ;