This configuration is for:

• SC602 – Memory module with MMU
• SC691 – Modular Z80 system (includes SC602 memory)
• SC720 – Z80 SBC / motherboard
• SC714 – Memory module with MMU
• SC721 – Memory module used with Z80+MMU (eg. SC730)
• SC791 – Modular Z80 system (includes SC714 memory)
• SC794 – Modular Z80 system (includes SC721 + SC730)
• and any other compatible systems

The latest release of this Firmware is detailed in the table below.

Name	Wayne Warthen’s RomWBW
Build name	RCZ80
Build date	2025-05-21
Platform	RCZ80
Configuration	std
Release	v3.5.1
Download ROM image	RomWBW-RCZ80_std v3.51 Dated 2025-05-21
Suggested ROM label	RomWBW RCZ80_std
Device Programming:
Code size	512k bytes
Checksum	02EA 7BD3 (MiniPro 6.85, SST39SF040)
Recommended IC	SST39SF040-70

The firmware is supplied (above) as a binary format file, which is suitable for use by most PROM programmers.

RomWBW’s documentation can be found here.

The very latest version, source code and documentation for RomWBW can be found here.

Supported Devices

This version of RomWBW supports the following devices.

Device	I/O Address
CPU: Z80 (eg. Z84C0010)	n/a
Memory: (with MMU type Z2) 512k Flash, 512k RAM	0x78 (to 0x7C)
LCD module (alpha-numeric)	0xDA (to 0xDB)
UART single channel serial #1	0x80 (to 0x87)
UART single channel serial #2	0x88 (to 0x8F)
UART single channel serial #3	0xA0 (to 0xA7)
UART single channel serial #4	0xA8 (to 0xAF)
Z80 SIO dual channel serial #1	0x80 (to 0x83)
Z80 SIO dual channel serial #2	0x84 (to 0x87)
ACIA single channel serial #1	0x80 (to 0x81)
ACIA single channel serial #2	0x40 (to 0x41) not enabled
Real-time clock (DS1302)	0xC0
Floppy disk (RCWDC)	0x50
8-bit IDE direct on CPU bus Compact Flash controller	0x10 (to 0x17)
PPIDE (parallel port IDE)	0x20
SD card (PIO, bit-bang)	0x69
USB device #1 (CH375/376)	0x3E
USB device #2 (CH375/376)	0x3C
Front panel / diagnostic LEDs	0x00
Front panel config. switches	0x00
Status LED	not enabled
Z80 CTC quad counter/timer	not enabled
Sound (AY chip)	not enabled

The lack of specific support does not exclude the use of other hardware. It just means the ROM does not do anything specific with it. Some additional hardware can be enabled by customising RomWBW, which is quite easy to do.

Supported Modules

This version of RomWBW supports the following 80-pin RCBus modules (SC700 series).

RCBus-80pin (700 series)	Function	I/O address
SC705	ACIA single serial #1 ACIA single serial #2	#1: 0x80 (to 0x81) #2: not enabled
SC706	Z80 CPU module Use with SC714	n/a
SC714	Memory with MMU Use with SC706	0x78 (to 0x7B)
SC715	Compact Flash interface	0x10 (to 0x17)
SC716	Z80 SIO/2 dual serial #1 Z80 SIO/2 dual serial #2	0x80 (to 0x83) 0x84 (to 0x87)
SC718	Z80 CTC module	0x88 (to 0x8B) not enabled
SC719	Digital I/O module (front panel LEDs & switches)	0x00
SC720	Z80 SBC / motherboard
SC721	Memory without MMU Use with SC730	n/a
SC725	Z80 SIO serial + CTC (requires 7.3728MHz oscillator or CLK2)	SIO: 0x80 (to 0x83) CTC: 0x88 (to 0x8B) CTC not enabled
SC727	RTC and I2C master	0xC0
SC730	Z80 CPU + MMU Use with SC721	0x78 (to 0x7B)
SC791	Z80 RomWBW computer
SC794	Z80 RomWBW computer

Plus the following 40-pin RCBus modules (SC600 series)

RCBus-40pin (600 series)	Function	I/O address
SC601	Z80 CPU module with diagnostic LEDs	0x00
SC602	Memory with MMU	0x78 (to 0x7B)
SC603	Z80 SIO/2 dual serial #1 Z80 SIO/2 dual serial #2	#1: 0x80 (to 0x83) #2: 0x84 (to 0x87)
SC604	Compact Flash interface	0x10 (to 0x17)
SC605	Digital I/O module (front panel LEDs & switches)	0x00
SC606	Real-time clock (DS1302)	0xC0
SC610	ACIA single serial #1 ACIA single serial #2	#1: 0x80 (to 0x81) #2: not enabled
SC611	SD card (PIO, bit-bang)	0x69
SC612	ACIA single serial #1 ACIA single serial #2	#1: 0x80 (to 0x81) #2: not enabled
SC613	Compact Flash interface	0x10 (to 0x17)
SC691	Z80 RomWBW computer

It also supports the following older modules (SC100 series)

RCBus (100 series)	Function	I/O address
SC104	Z80 SIO/2 dual serial #1 Z80 SIO/2 dual serial #2	0x80 (to 0x83) 0x84 (to 0x87)
SC129	Digital I/O module (front panel LEDs & switches)	0x00
SC132	Z80 SIO/0 dual serial #1 Z80 SIO/0 dual serial #2	0x80 (to 0x83) 0x84 (to 0x87)
SC135	Digital outputs (front panel LEDs)	0x00
SC136	Digital inputs (from panel switches)	0x00
SC139	ACIA serial port	0x80 (to 0x81)
SC145	Compact Flash interface	0x10 (to 0x17)
SC149	Z80 CPU module	n/a
SC153	Z80 CPU module	n/a

The lack of specific support does not exclude the use of other hardware. It just means the ROM does not do anything specific with it.

Incompatible modules

Modules not compatible with this configuration:

Device	Comment
SC707 SC708 SC108 SC143 SC150 SC151 SC152	Insufficient memory RomWBW requires 512k RAM

Release Notes

The Z180’s internal I/O is set to the range 0xC0 to 0xFF.

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OLDER RELEASES

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RomWBW v3.4.0

The latest release of this Firmware is detailed in the table below.

Name	Wayne Warthen’s RomWBW
Platform	RCZ80
Configuration	std
Release	v3.4.0, 2023-12-31
Download	RomWBW RCZ80_std v3.4.0 Dated 2023-12-31
Device Programming:
Code size	512k bytes
Checksum	02FA A637 (MiniPro 6.85, SST39SF040)
Recommended IC	SST39SF040-70

Core Components:
HBIOS	VersioVersion 3.4.0, 2023-12-31
Included Apps:
– CamelForth	Version 1.02, 2021-09-07
– CP/M	Version 2.2, CBIOS v3.4.0 [WBW]
– Monitor	Version unknown
– NASCOM BASIC	Version 4.7b
– Tasty BASIC	Version 0.3.0
– Z-System	Version 1.1, CBIOS v3.4.0 [WBW]

The firmware is supplied (above) as a binary format file, which is suitable for use by most PROM programmers.

RomWBW’s documentation can be found here.

The very latest version, source code and documentation for RomWBW can be found here.

Supported Devices

This version of RomWBW supports the following devices.

Device	I/O Address
CPU: Z80 (eg. Z84C0010)	n/a
Memory: (with MMU type Z2) 512k Flash, 512k RAM	0x78 (to 0x7C)
SD card enable bit (shares real-time clock address)	not supported
Real-time clock (DS1302) (shares SD card enable address)	0xC0
Status LED	not supported
Front panel / diagnostic LEDs	0x00
Front panel config. switches	0x00
Z80 SIO dual serial #1	0x80 (to 0x83)
Z80 SIO dual serial #2	0x84 (to 0x87)
Z80 CTC quad counter/timer	0x88 (to 0x8B)
ACIA single channel serial #1	0x80 (to 0x81)
ACIA single channel serial #2	not supported
8-bit IDE direct on CPU bus Compact Flash controller	0x10 (to 0x17)
PPIDE (parallel port IDE)	0x20
Sound (AY chip)	not supported
Floppy disk	0x50
USB device #1 (CH375/376)	0x3E
USB device #2 (CH375/376)	0x3C

The lack of specific support does not exclude the use of other hardware. It just means the ROM does not do anything specific with it. Some additional hardware can be supported by customising RomWBW, which is quite easy to do.

Supported Modules

This version of RomWBW supports the following 80-pin RCBus modules (SC700 series).

RCBus-80pin (700 series)	Function	I/O address
SC705	ACIA serial module	0x80 (to 0x81)
SC706	Z80 CPU module Use with SC714	n/a
SC714	Memory with MMU Use with SC706	0x78 (to 0x7B)
SC715	Compact Flash interface	0x10 (to 0x17)
SC716	Z80 SIO/2 dual serial #1 Z80 SIO/2 dual serial #2	0x80 (to 0x83) 0x84 (to 0x87)
SC718	Z80 CTC module	0x88 (to 0x8B)
SC719	Digital I/O module (used for diagnostic LEDs)	0x00
SC720	Z80 SBC / motherboard
SC721	Memory without MMU Use with SC730	n/a
SC725	Z80 SIO serial + CTC (requires 7.3728MHz oscillator or CLK2)	0x80 (to 0x83) plus CTC 0x88 (to 0x8B)
SC727	RTC and I2C master	0xC0
SC730	Z80 CPU + MMU Use with SC721	n/a
SC791	Z80 RomWBW computer

It also supports the following older modules (SC100 series)

RCBus (100 series)	Function	I/O address
SC104	Z80 SIO/2 dual serial #1	0x80 (to 0x83)
SC104	Z80 SIO/2 dual serial #2	0x84 (to 0x87)
SC129	Digital I/O module (used for diagnostic LEDs)	0x00
SC132	Z80 SIO/0 dual serial #1	0x80 (to 0x83)
SC132	Z80 SIO/0 dual serial #2	0x84 (to 0x87)
SC139	ACIA serial port	0x80 (to 0x81)
SC145	Compact Flash interface	0x10 (to 0x17)
SC153	Z80 CPU module	n/a

The lack of specific support does not exclude the use of other hardware. It just means the ROM does not do anything specific with it.

Incompatible modules

Modules not compatible with this configuration:

Device	Comment
SC707 SC708 SC108 SC143 SC150 SC151 SC152	Insufficient memory RomWBW requires 512k RAM

Release Notes

The Z180’s internal I/O is set to the range 0xC0 to 0xFF.

RomWBW v3.2.1

Name	Wayne Warthen’s RomWBW
Platform	RCZ80
Configuration	std
Release	v3.2.1, 2023-06-03
Download	RomWBW RCZ80_std v3.2.1 Dated 2023-06-03
Device Programming:
Code size	512k bytes
Checksum	02F2 566A (MiniPro 6.85, SST39SF040)
Recommended IC	SST39SF040-70

Core Components:
HBIOS	Version 3.2.1, 2023-06-03
Included Apps:
– CamelForth	Version 1.02
– CP/M	Version 2.2, CBIOS v3.2.1 [WBW]
– Monitor	Version unknown
– NASCOM BASIC	Version 4.7b
– Tasty BASIC	Version 0.3.0
– Z-System	Version 1.1, CBIOS v3.2.1 [WBW]

The firmware is supplied (above) as a binary format file, which is suitable for use by most PROM programmers.

RomWBW’s documentation can be found here.

The very latest version, source code and documentation for RomWBW can be found here.

Supported Devices

• SC720 Z80 SBC/motherboard
• SC791 Z80 modular computer
  • Z80 CPU (eg. Z84C00xxPEG)
  • Z80 SIO dual serial ports @ 0x80
  • Z80 SIO dual serial ports @ 0x84 (giving up to 4 ports)
  • 68B50 ACIA serial port @ 0x80
  • Status LEDs at 0x00
  • Compact Flash at 0x10
  • Real time clock (DS1302) at 0xC0
  • Floppy disk at 0x50
  • PPIDE at 0x20

The lack of specific support does not exclude the use of other hardware. It just means the ROM does not do anything specific with it. Some additional hardware can be supported by customising RomWBW, which is quite easy to do.

Supported Modules

• Processor and memory:
  • SC720 Z80 SBC/motherboard
  • SC706, Z80 CPU
  • SC153, Z80 CPU

• Memory:
  • SC720 Z80 SBC/motherboard
  • SC714, Memory 512+512

• Serial ports:
  • SC720 Z80 SBC/motherboard
  • SC705, 68B50 ACIA
  • SC716, Z80 SIO/2
  • SC104, Z80 SIO/2
  • SC132, Z80 SIO/0
  • SC139, 68B50 ACIA

• Timer:
  • None

• Baud rate generation:
  • None (fixed by hardware)

• Mass storage (SD card):
  • None

• Mass storage (Compact Flash card)
  • SC720 Z80 SBC/motherboard
  • SC715, Compact Flash module
  • SC145, compact flash module

• Self-test status display: (LEDs)
  • SC720 Z80 SBC/motherboard
  • SC719, Digital I/O module
  • SC129, Digital I/O module
  • SC134, LED outputs

The lack of specific support does not exclude the use of other hardware. It just means the ROM does not do anything specific with it.

Release Notes

The Z180’s internal I/O is set to the range 0xC0 to 0xFF.