diff --git a/Doc/RomWBW Applications.pdf b/Doc/RomWBW Applications.pdf
index 82deb94e..fee6cd09 100644
Binary files a/Doc/RomWBW Applications.pdf and b/Doc/RomWBW Applications.pdf differ
diff --git a/Doc/RomWBW Disk Catalog.pdf b/Doc/RomWBW Disk Catalog.pdf
index d7fbf1c5..77aa1665 100644
Binary files a/Doc/RomWBW Disk Catalog.pdf and b/Doc/RomWBW Disk Catalog.pdf differ
diff --git a/Doc/RomWBW Hardware.pdf b/Doc/RomWBW Hardware.pdf
index 0869a23f..f340af68 100644
Binary files a/Doc/RomWBW Hardware.pdf and b/Doc/RomWBW Hardware.pdf differ
diff --git a/Doc/RomWBW Introduction.pdf b/Doc/RomWBW Introduction.pdf
index ffefee80..f864e4eb 100644
Binary files a/Doc/RomWBW Introduction.pdf and b/Doc/RomWBW Introduction.pdf differ
diff --git a/Doc/RomWBW System Guide.pdf b/Doc/RomWBW System Guide.pdf
index bbe15605..fde93401 100644
Binary files a/Doc/RomWBW System Guide.pdf and b/Doc/RomWBW System Guide.pdf differ
diff --git a/Doc/RomWBW User Guide.pdf b/Doc/RomWBW User Guide.pdf
index 2501812b..72c95438 100644
Binary files a/Doc/RomWBW User Guide.pdf and b/Doc/RomWBW User Guide.pdf differ
diff --git a/ReadMe.md b/ReadMe.md
index d29cd249..532d20d0 100644
--- a/ReadMe.md
+++ b/ReadMe.md
@@ -7,7 +7,7 @@
 **RomWBW Introduction** \
 Version 3.6 \
 Wayne Warthen  ([wwarthen@gmail.com](mailto:wwarthen@gmail.com)) \
-12 Nov 2025
+14 Nov 2025
 
 # Overview
 
diff --git a/ReadMe.txt b/ReadMe.txt
index 838c1c23..afca823d 100644
--- a/ReadMe.txt
+++ b/ReadMe.txt
@@ -1,6 +1,6 @@
 RomWBW Introduction
 Wayne Warthen (wwarthen@gmail.com)
-12 Nov 2025
+14 Nov 2025
 
 
 
diff --git a/Source/Doc/Hardware.md b/Source/Doc/Hardware.md
index 111716da..4a5e0c25 100644
--- a/Source/Doc/Hardware.md
+++ b/Source/Doc/Hardware.md
@@ -2492,6 +2492,7 @@ Note:
 | PCF       | PCF8584-based I2C Real-Time Clock                      |
 | RP5C01    | Ricoh RPC01A Real-Time Clock w/ NVRAM                  |
 | SIMRTC    | SIMH Simulator Real-Time Clock                         |
+| MMRTC     | NS MM58167B Real-Time Clock (no NVRAM)                 |
 
 ## DsKy (DiSplay KeYpad)
 
diff --git a/Source/Doc/SystemGuide.md b/Source/Doc/SystemGuide.md
index ee156f40..8ba0a02f 100644
--- a/Source/Doc/SystemGuide.md
+++ b/Source/Doc/SystemGuide.md
@@ -1430,6 +1430,7 @@ unit.  The table below enumerates these values.
 | RTCDEV_RP5      | 0x05   | Ricoh RPC01A Real-Time Clock w/ NVRAM    | rp5rtc.asm  |
 | RTCDEV_EZ80     | 0x07   | eZ80 on-chip RTC                         | ez80rtc.asm |
 | RTCDEV_PC       | 0x08   | MC146818/DS1285/DS12885 RTC w/ NVRAM     | pcrtc.asm   |
+| RTCDEV_MM       | 0x09   | NS MM58167B RTC (no NVRAM)               | mmrtc.asm   |
 
 The time functions to get and set the time (RTCGTM and RTCSTM) require a
 6 byte date/time buffer in the following format. Each byte is BCD 
diff --git a/Source/HBIOS/Config/SZ180_std.asm b/Source/HBIOS/Config/SZ180_std.asm
index 9756ecdb..5e4a42ed 100644
--- a/Source/HBIOS/Config/SZ180_std.asm
+++ b/Source/HBIOS/Config/SZ180_std.asm
@@ -58,6 +58,7 @@ Z180_MEMWAIT	.SET	1		; Z180: MEMORY WAIT STATES (0-3)
 Z180_IOWAIT	.SET	3		; Z180: I/O WAIT STATES TO ADD ABOVE 1 W/S BUILT-IN (0-3)
 ;
 INTRTCENABLE	.SET	TRUE		; ENABLE PERIODIC INTERRUPT CLOCK DRIVER (INTRTC.ASM)
+MMRTCENABLE	.SET	TRUE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
 ;
 ASCIENABLE	.SET	TRUE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 PLDSERENABLE	.SET	TRUE		; PLDSER: ENABLE PLD-USB SERIAL DRIVER (PLDSER.ASM)
diff --git a/Source/HBIOS/Config/SZ80_std.asm b/Source/HBIOS/Config/SZ80_std.asm
index 8cc33832..0dc552ce 100644
--- a/Source/HBIOS/Config/SZ80_std.asm
+++ b/Source/HBIOS/Config/SZ80_std.asm
@@ -55,6 +55,8 @@ MEMMGR		.SET	MM_SZ80		; MEMORY MANAGER: MM_[SBC|Z2|N8|Z180|Z280|MBC|RPH|MON|EZ51
 FPLED_ENABLE	.SET	TRUE		; FP: ENABLES FRONT PANEL LEDS
 FPLED_IO	.SET	$05		; FP: PORT ADDRESS FOR FP LEDS
 ;
+MMRTCENABLE	.SET	TRUE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 PLDSERENABLE	.SET	TRUE		; PLDSER: ENABLE PLD-USB SERIAL DRIVER (PLDSER.ASM)
 SCCENABLE	.SET	TRUE		; SCC: ENABLE ZILOG SCC SERIAL DRIVER (SCC.ASM)
 SCONENABLE	.SET	TRUE		; SCON: ENABLE S100 CONSOLE DRIVER (SCON.ASM)
diff --git a/Source/HBIOS/cfg_DUO.asm b/Source/HBIOS/cfg_DUO.asm
index 34b781d1..080b6659 100644
--- a/Source/HBIOS/cfg_DUO.asm
+++ b/Source/HBIOS/cfg_DUO.asm
@@ -169,6 +169,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_DYNO.asm b/Source/HBIOS/cfg_DYNO.asm
index f1c8a60a..5958754f 100644
--- a/Source/HBIOS/cfg_DYNO.asm
+++ b/Source/HBIOS/cfg_DYNO.asm
@@ -168,6 +168,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_EPITX.asm b/Source/HBIOS/cfg_EPITX.asm
index f088e2cd..d52146de 100644
--- a/Source/HBIOS/cfg_EPITX.asm
+++ b/Source/HBIOS/cfg_EPITX.asm
@@ -164,6 +164,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_EZZ80.asm b/Source/HBIOS/cfg_EZZ80.asm
index 6d390851..812c7c27 100644
--- a/Source/HBIOS/cfg_EZZ80.asm
+++ b/Source/HBIOS/cfg_EZZ80.asm
@@ -168,6 +168,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_GMZ180.asm b/Source/HBIOS/cfg_GMZ180.asm
index f1522dfc..1b4c61b8 100644
--- a/Source/HBIOS/cfg_GMZ180.asm
+++ b/Source/HBIOS/cfg_GMZ180.asm
@@ -163,6 +163,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_HEATH.asm b/Source/HBIOS/cfg_HEATH.asm
index d1654feb..91800be5 100644
--- a/Source/HBIOS/cfg_HEATH.asm
+++ b/Source/HBIOS/cfg_HEATH.asm
@@ -168,6 +168,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_MASTER.asm b/Source/HBIOS/cfg_MASTER.asm
index abcc84f9..1235ad56 100644
--- a/Source/HBIOS/cfg_MASTER.asm
+++ b/Source/HBIOS/cfg_MASTER.asm
@@ -204,6 +204,8 @@ DS7RTCMODE	.EQU	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.EQU	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.EQU	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 PCRTCENABLE	.EQU	FALSE		; PCRTC: DISABLE DS12885 etc. RTC
 PCRTC_BASE	.EQU	$C0		; Default port for PCRTC, like DSRTC.
 ;
diff --git a/Source/HBIOS/cfg_MBC.asm b/Source/HBIOS/cfg_MBC.asm
index 88142215..0341cc12 100644
--- a/Source/HBIOS/cfg_MBC.asm
+++ b/Source/HBIOS/cfg_MBC.asm
@@ -162,6 +162,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTC_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_MK4.asm b/Source/HBIOS/cfg_MK4.asm
index 37cbb121..e0575cbc 100644
--- a/Source/HBIOS/cfg_MK4.asm
+++ b/Source/HBIOS/cfg_MK4.asm
@@ -168,6 +168,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_MON.asm b/Source/HBIOS/cfg_MON.asm
index 810264aa..6a04af30 100644
--- a/Source/HBIOS/cfg_MON.asm
+++ b/Source/HBIOS/cfg_MON.asm
@@ -165,6 +165,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_MSX.asm b/Source/HBIOS/cfg_MSX.asm
index a96a7d1f..d06b8dda 100644
--- a/Source/HBIOS/cfg_MSX.asm
+++ b/Source/HBIOS/cfg_MSX.asm
@@ -171,6 +171,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_N8.asm b/Source/HBIOS/cfg_N8.asm
index 97248512..b30ac4fa 100644
--- a/Source/HBIOS/cfg_N8.asm
+++ b/Source/HBIOS/cfg_N8.asm
@@ -170,6 +170,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_NABU.asm b/Source/HBIOS/cfg_NABU.asm
index 0684a188..28f79467 100644
--- a/Source/HBIOS/cfg_NABU.asm
+++ b/Source/HBIOS/cfg_NABU.asm
@@ -168,6 +168,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_RCEZ80.asm b/Source/HBIOS/cfg_RCEZ80.asm
index 9d2f16b6..2d2c57c5 100644
--- a/Source/HBIOS/cfg_RCEZ80.asm
+++ b/Source/HBIOS/cfg_RCEZ80.asm
@@ -166,6 +166,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_RCZ180.asm b/Source/HBIOS/cfg_RCZ180.asm
index 4b05b6a0..ec016b6e 100644
--- a/Source/HBIOS/cfg_RCZ180.asm
+++ b/Source/HBIOS/cfg_RCZ180.asm
@@ -168,6 +168,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_RCZ280.asm b/Source/HBIOS/cfg_RCZ280.asm
index 5da29efd..8e5bc2df 100644
--- a/Source/HBIOS/cfg_RCZ280.asm
+++ b/Source/HBIOS/cfg_RCZ280.asm
@@ -168,6 +168,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_RCZ80.asm b/Source/HBIOS/cfg_RCZ80.asm
index 4b92aa26..66f04201 100644
--- a/Source/HBIOS/cfg_RCZ80.asm
+++ b/Source/HBIOS/cfg_RCZ80.asm
@@ -171,6 +171,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_RPH.asm b/Source/HBIOS/cfg_RPH.asm
index 521ad9b2..d260bd44 100644
--- a/Source/HBIOS/cfg_RPH.asm
+++ b/Source/HBIOS/cfg_RPH.asm
@@ -168,6 +168,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_SBC.asm b/Source/HBIOS/cfg_SBC.asm
index a41e3c88..3b4d9d65 100644
--- a/Source/HBIOS/cfg_SBC.asm
+++ b/Source/HBIOS/cfg_SBC.asm
@@ -163,6 +163,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_SCZ180.asm b/Source/HBIOS/cfg_SCZ180.asm
index b1ef1195..01b0973d 100644
--- a/Source/HBIOS/cfg_SCZ180.asm
+++ b/Source/HBIOS/cfg_SCZ180.asm
@@ -168,6 +168,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_SZ180.asm b/Source/HBIOS/cfg_SZ180.asm
index aba96380..a355116c 100644
--- a/Source/HBIOS/cfg_SZ180.asm
+++ b/Source/HBIOS/cfg_SZ180.asm
@@ -165,6 +165,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 ;
 PLDSERENABLE	.SET	FALSE		; PLDSER: ENABLE PLD-USB SERIAL DRIVER (PLDSER.ASM)
diff --git a/Source/HBIOS/cfg_SZ80.asm b/Source/HBIOS/cfg_SZ80.asm
index 4b4a813e..753122da 100644
--- a/Source/HBIOS/cfg_SZ80.asm
+++ b/Source/HBIOS/cfg_SZ80.asm
@@ -158,6 +158,10 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 ;
 PLDSERENABLE	.SET	FALSE		; PLDSER: ENABLE PLD-USB SERIAL DRIVER (PLDSER.ASM)
diff --git a/Source/HBIOS/cfg_Z80RETRO.asm b/Source/HBIOS/cfg_Z80RETRO.asm
index 28d3a0fc..0de6f6de 100644
--- a/Source/HBIOS/cfg_Z80RETRO.asm
+++ b/Source/HBIOS/cfg_Z80RETRO.asm
@@ -166,6 +166,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_ZETA.asm b/Source/HBIOS/cfg_ZETA.asm
index 283da8b9..cb253639 100644
--- a/Source/HBIOS/cfg_ZETA.asm
+++ b/Source/HBIOS/cfg_ZETA.asm
@@ -155,6 +155,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/cfg_ZETA2.asm b/Source/HBIOS/cfg_ZETA2.asm
index f2e126b0..11501264 100644
--- a/Source/HBIOS/cfg_ZETA2.asm
+++ b/Source/HBIOS/cfg_ZETA2.asm
@@ -166,6 +166,8 @@ DS7RTCMODE	.SET	DS7RTCMODE_PCF	; DS7RTC: OPERATING MODE: DS7RTCMODE_[PCF]
 ;
 DS5RTCENABLE	.SET	FALSE		; DS5RTC: ENABLE DS-1305 SPI CLOCK DRIVER (DS5RTC.ASM)
 ;
+MMRTCENABLE	.SET	FALSE		; MMRTC: ENABLE NS MM58167B RTC DRIVER (MMRTC.ASM)
+;
 SSERENABLE	.SET	FALSE		; SSER: ENABLE SIMPLE SERIAL DRIVER (SSER.ASM)
 SSERCFG		.SET	SER_9600_8N1	; SSER: SERIAL LINE CONFIG
 SSERSTATUS	.SET	$FF		; SSER: STATUS PORT
diff --git a/Source/HBIOS/hbios.asm b/Source/HBIOS/hbios.asm
index a5a90614..ea69ed34 100644
--- a/Source/HBIOS/hbios.asm
+++ b/Source/HBIOS/hbios.asm
@@ -4257,9 +4257,6 @@ HB_INITTBL:
 #IF (SIMRTCENABLE)
 	.DW	SIMRTC_INIT
 #ENDIF
-#IF (INTRTCENABLE)
-	.DW	INTRTC_INIT
-#ENDIF
 #IF (DS7RTCENABLE)
 	.DW	DS7RTC_INIT
 #ENDIF
@@ -4275,6 +4272,12 @@ HB_INITTBL:
 #IF (PCRTCENABLE)
 	.DW	PCRTC_INIT
 #ENDIF
+#IF (MMRTCENABLE)
+	.DW	MMRTC_INIT
+#ENDIF
+#IF (INTRTCENABLE)
+	.DW	INTRTC_INIT
+#ENDIF
 #IF (CPUFAM == CPU_EZ80)
 	; INITALISE ONE OF THE SUPPORTED SYSTEM TIMER TICKS DRIVERS
 	.DW	EZ80_TMR_INIT
@@ -8865,15 +8868,6 @@ SIZ_PCRTC	.EQU	$ - ORG_PCRTC
 		MEMECHO	" bytes.\n"
 #ENDIF
 ;
-#IF (INTRTCENABLE)
-ORG_INTRTC	.EQU	$
-  #INCLUDE "intrtc.asm"
-SIZ_INTRTC	.EQU	$ - ORG_INTRTC
-		MEMECHO	"INTRTC occupies "
-		MEMECHO	SIZ_INTRTC
-		MEMECHO	" bytes.\n"
-#ENDIF
-;
 #IF (DS7RTCENABLE)
 ORG_DS7RTC	.EQU	$
   #INCLUDE "ds7rtc.asm"
@@ -8892,6 +8886,24 @@ SIZ_RP5RTC	.EQU	$ - ORG_RP5RTC
 		MEMECHO	" bytes.\n"
 #ENDIF
 ;
+#IF (MMRTCENABLE)
+ORG_MMRTC	.EQU	$
+  #INCLUDE "mmrtc.asm"
+SIZ_MMRTC	.EQU	$ - ORG_MMRTC
+		MEMECHO	"MMRTC occupies "
+		MEMECHO	SIZ_MMRTC
+		MEMECHO	" bytes.\n"
+#ENDIF
+;
+#IF (INTRTCENABLE)
+ORG_INTRTC	.EQU	$
+  #INCLUDE "intrtc.asm"
+SIZ_INTRTC	.EQU	$ - ORG_INTRTC
+		MEMECHO	"INTRTC occupies "
+		MEMECHO	SIZ_INTRTC
+		MEMECHO	" bytes.\n"
+#ENDIF
+;
 #IF (SSERENABLE)
 ORG_SSER	.EQU	$
   #INCLUDE "sser.asm"
diff --git a/Source/HBIOS/hbios.inc b/Source/HBIOS/hbios.inc
index 9032b151..e20bf0c1 100644
--- a/Source/HBIOS/hbios.inc
+++ b/Source/HBIOS/hbios.inc
@@ -438,6 +438,7 @@ RTCDEV_RP5	.EQU	$05		; RP5C01
 RTCDEV_DS5	.EQU	$06		; DS1305 (SPI)
 RTCDEV_EZ80	.EQU	$07		; EZ80 ON-CHIP RTC
 RTCDEV_PC	.EQU	$08		; PC style parallel RTC
+RTCDEV_MM	.EQU	$09		; NS MM58167B RTC (NO NVRAM)
 ;
 ; DSKY DEVICE IDS
 ;
diff --git a/Source/HBIOS/romldr.asm b/Source/HBIOS/romldr.asm
index dcdaf5a8..3d4f83f0 100644
--- a/Source/HBIOS/romldr.asm
+++ b/Source/HBIOS/romldr.asm
@@ -1230,26 +1230,26 @@ appload2:
 ;
 ;=======================================================================
 ; Routine - Copy chunk of data from Rom to a RAM location, source
-; chunk may span banks.
+; chunk may span banks.  Source address must be <= 32768.
 ; param : HL=Source Adr, DE=Dest Adr, BC=Length, A=Source Bank
 ;=======================================================================
 ;
-;;; loop:
-;;; 
-;;; CPYLEN = (32768 - SRCADR)
-;;; if (CPYLEN >= LEN) then CPYLEN = LEN
-;;; LEN = (LEN - CPYLEN)	; do it here to avoid saving CPYLEN
-;;; 
-;;; ; BnkCpy returns updated SRCADR, DSTADR
-;;; call BnkCpy(SRCBNK:SRCADR, DSTBNK:DSTADR, CPYLEN)
-;;; 
-;;; if (SRCADR == 32768)
-;;;   increment SRCBNK
-;;;   SRCADR = 0
-;;; 
-;;; if (LEN == 0) then done
-;;; 
-;;; goto loop
+; loop:
+; 
+; CPYLEN = (32768 - SRCADR)
+; if (CPYLEN >= LEN) then CPYLEN = LEN
+; LEN = (LEN - CPYLEN)	; do it here to avoid saving CPYLEN
+; 
+; ; BnkCpy returns updated SRCADR, DSTADR
+; call BnkCpy(SRCBNK:SRCADR, DSTBNK:DSTADR, CPYLEN)
+; 
+; if (SRCADR == 32768)
+;   increment SRCBNK
+;   SRCADR = 0
+; 
+; if (LEN == 0) then done
+; 
+; goto loop
 ;
 #if (BIOS == BIOS_WBW)
 ;