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N8VEM

March 03, 2023

N8VEM was a homebrew computing project. It featured a variety of free and open hardware and software. N8VEM builders made their own homebrew computer systems for themselves and shared their experiences with other homebrew computer hobbyists. N8VEM homebrew computer components are made in the style of vintage computers of the mid to late 1970s and early 1980s using a mix of classic and modern technologies. They are designed with ease of amateur assembly in mind.

In November 2015 the N8VEM project was ended by its creator Andrew Lynch and the community reconvened under the new name of Retrobrew Computers.

Creation and operation

There are several N8VEM designs starting with a single-board computer carrying a Z80 microprocessor designed to run CP/M and similar operating systems. It was created in 2008 by Andrew Lynch. Contrasted with the P112, which has some surface-mount components, the N8VEM SBC uses only through-hole components, consistent with the design philosophy that building should be within the skills and resources of non-professional hobbyists. The project has also developed boards for other processors including Z180, Intel 80188, MOS 6502, Motorola 6809, 68000 and 68030.

The N8VEM boards are designed with the free KiCad Electronic design automation (EDA) toolset. Printed circuit board routing provided by FreeRouting.net. Software is developed in Z80/8085 assembly language using the MS-DOS Telemark Cross Assembler program (TASM), as well as the open source Small Device C Compiler. A major design goal is to use freely available tools to the maximum extent possible. The printed circuit board design is supplemented using component libraries available at KiCad Libraries, specifically the Zilog Z80 CPU and Intel 8255 PPI chips.

The design philosophy encourages low cost development and assembly by hobbyist amateurs using common tools such as 25 watt soldering iron, multimeter, logic probe (optional), and common hand tools. An oscilloscope is recommended but not required. Some basic electronic skills are helpful although the printed circuit boards are designed for relative beginners.

There are numerous N8VEM components available including ECB[1] and S-100 backplane boards, allow processor and expansion boards to be connected. Other components include video boards, disk controllers, peripheral expansion, and prototyping boards.

In response to interest from members, the N8VEM homebrew computing project has collaborated in developing a range of boards for the S-100 bus. These can be used to build new systems from scratch on that historic industry standard platform, or to restore and enhance vintage S-100 systems preserved from the 1970s and 1980s. Most of the S-100 board initial design work has been contributed by John Monahan of s100computers.com, with board layout, prototyping and testing contributed by Andrew Lynch and other N8VEM supporters. Some of these S-100 boards provide enhanced capabilities beyond what was available on original S-100 machines, some are replacements for historic S-100 boards, and other board projects aim to apply the convenient bus architecture to processor families beyond the 8080/Z80 CPUs for which the bus standard was originally designed: notably 6502, 68000, and later Intel processor types.[2]

N8VEM is notable for being the largest and most active homebrew computing community in existence today. The project is entirely non-commercial and is made up of over 350 hobbyists,[3][4] many of whom are actively involved in designing and prototyping the hardware and software.[5] The community is a modern-day version of the historic Homebrew Computer Club frequented by Steve Wozniak and other pioneers of home computer development. Printed circuit boards of the mature designs are manufactured in small batches on a collective order basis, and distributed to members for the cost of the board manufacturing and shipping. The project does not provide complete kits—builders must procure their own parts to populate a board. Support is purely on a volunteer basis through a Google Group and Wiki. Software is open source and freely available for download from the Wiki. The project was careful to keep things within the reach of the amateur computer hobbyist by using low cost and readily available components that can be assembled with simple hand tools.

In addition, notable freeware system emulator SIMH[6] simulates the N8VEM SBC (along with many other architectures), providing a virtualised development environment that has the speed and flexibility of modern hardware.

Completed N8VEM hardware and software has frequently been displayed at Vintage Computer Festivals.[7][8]

Single board computers

ECB Bus:

  1. SBC V2 (Z80, UART, PPI, RAM with battery backup, ROM, RTC)
  2. SBC-188 (80C188 10-25 MHz, UART, PPI, RAM with battery backup, ROM, RTC, FDC)
  3. N8 Home Computer (Z8S180 33 MHz, UART, ROM, RTC, Dual Interrupt controllers, Floppy, SD Card, 1MB RAM, AY-3-8910 sound, TMS9918A video, ECB bus)
  4. SBC Mark IV (Z180 processor, 512K SRAM, 512K Flash or 1MB EPROM, RTC, SD Card, 8-bit IDE, RS-232, RS-422, ECB bus)
  5. KISS 68030 (68030 processor up to 32MHz, up to 256M DRAM, 32K SRAM, 512K Flash, ECB bus)

S-100 bus:

  1. Z80 S-100
  2. m68k S-100 (In progress)
  3. 8086 S-100 (In progress)
  4. 6502/6809 ECB + carrier boards for other cpu's (?)

Other:

  1. SBC6120-RBC: A new edition of the Spare Time Gizmos SBC6120 Model 2 updated to use easily available RAM and EEPROM components, only two PCB layers, and KiCAD.

ECB expansion peripherals

  • ECB Backplane (compact stand alone with 8 DIN 41612 slots)
  • ECB Bus Monitor (single step, address trap, bus status)
  • Disk IO (FDC & IDE (Parallel ATA) drive expansion)
  • Zilog Peripherals (CTC, DART, dual PIOs)
  • Video Display Unit (80×25 character mode video)
  • Prototyping board with IO decode (buffered with labeled signal connectors)
  • ECB Extended backplane (12 slot with 3U mounting features)
  • DSKY (monitor/boot loader Hex LED display and keypad)
  • Sprites, Color Graphics, & Sound (TMS9918, AY-3-8910, joystick/paddle interface)
  • Prop IO (VGA, PS/2 keyboard, PS/2 mouse, micro SD (Secure Digital), prototyping area)
  • Cassette Interface (KCS audio cassettes)
  • 4MEM (4MB SRAM expansion for SBC-188)
  • PPIDE (SBC parallel expansion port IDE interface)
  • Juha SD (SBC SD card for mass storage)
  • MSX Cartridge reader (load contents of MSX cartridges)
  • MSX Cartridge (8K, 16K, & 32K EPROMs)
  • µPD7220 V2 prototype (16 color video display)
  • RAM-Floppy (4MB SRAM floppy drive replacement)
  • 4PIO (64 GPIO input/output board)
  • ECB to Z80 socket adapter (connect ECB boards directly to Z80 CPU)
  • 6x0x host processor (Motorola 6800), MOS Technology 6502 CPU with ECB interface)
  • 6x0x IO mezzanine (ACIA, dual PIA, PTC, power, and expansion bus interface)
  • 6x0x ECB backplane (use ECB peripherals with stand alone 6x0x system)

There is an active community development forum (N8VEM Google Discussion Group) from which additional board designs have been developed. There is active development of new boards underway.

System software

RomWBW is a popular system software distribution written to execute on N8VEM hardware.

The N8VEM family of hardware are primarily Z80 based microprocessor single board computers, as well as miscellaneous boards which may be combined and placed in an ECB-like bus, enabling the builder to create a custom computer system. These computers are primarily built from discrete components as were computers in the late 1970s and 1980s. The majority of the systems are Z80 based and use the CP/M-80 operating system that was developed in the late 1970s by Digital Research, Inc.

The RomWBW system software is highly configurable and supports all of the Z80 based systems constructed with N8VEM components. The system software is entirely open source and is provided in both machine readable source form and as pre-built images for those wishing to program firmware chips for insertion in the boards.

In addition to the fully implemented operating system with its BIOS (customized for the N8VEM hardware), there are several dozen utility programs that configure and verify the proper operation of system components such as persistent storage in the form of IDE Hard Drives, Compact Flash, and Secure Digital chips.

The CP/M-80 BIOS is written in assembly language and is built using the TASM assembler. Utility programs are written in a variety of languages including assembler, Digital Research RMAC, Aztec C, and Digital Research PLI. These natively hosted programming languages, and tools such as WordStar (a popular editor of the time), execute under the CP/M operating system and read source files stored on memory disk or persistent media such as IDE devices or Compact Flash and Secure Digital devices through the use of an external adapter.

The version 1.x distributions of the system software have been written in a very standard CP/M-80 way and over the course of a half dozen releases has reached a highly stable state supporting the most commonly built configurations in use. The version 2.x operating software was recently released and uses bank switched memory technology to achieve enhanced functionality. Due to the new technology, there are no practical limits on the number of drivers that can be built in. In the future, this will allow for dynamic configuration and will be much more flexible for the users, in many ways similar to the CP/M-80 Plus family of operating systems which also took advantage of memory paging.

In the same way the hardware is open source, the software is provided in source form as well allowing users to both learn how software was written in the early days of microprocessors, but also to write new software using provided tools and documentation available both in the distribution, on the subversion server, and downloadable from a variety of public archives worldwide.

The current owners of the Digital Research, Inc operating systems and language software have licensed it for non-commercial use and the most comprehensive archives can be found at http://www.cpm.z80.de as well as other popular locations and mirrors.

An alternative system BIOS, UNA BIOS, also exists. It has the advantage that a single ROM image can run on all Z80 and Z180 systems. An alternative CP/M implementation, UNA CP/M, takes advantage of UNA BIOS disk and device drivers.

References

  1. ^ "N8VEM". Hd64180-ecb.de. Retrieved 2016-04-01.
  2. ^ "S100 Computers". S100 Computers. Retrieved 2016-04-01.
  3. ^ "Rich Cini's Computer Lab - N8VEM SBC". Classiccmp.org. 2016-02-20. Retrieved 2016-04-01.
  4. ^ "First Project: N8VEM Single Board Computer | Nathan's build log". Thomasns.wordpress.com. 2009-10-26. Retrieved 2016-04-01.
  5. ^ "N8VEM computer with a 3Km wireless link". Hackaday. 2009-03-04. Retrieved 2016-04-01.
  6. ^ "Altair Other Operating Systems". Schorn.ch. Retrieved 2016-04-01.
  7. ^ "Vintage Computer Festival". Vintage.org. Retrieved 2016-04-01.
  8. ^ Finnegan, Patrick (2010-09-18). "N8VEM exhibit | Flickr - Photo Sharing!". Flickr. Retrieved 2016-04-01.

Further reading

  • Vermeulen, Oscar; Andrew Lynch (July 2013). "DIY Single-Board Computers (Part I)". Circuit Cellar (276): 44–47.
  • Wilson, Mary (June 2013). "DIY Single-Board Computers". Circuit Cellar.
  • Vermeulen, Oscar (2013). "Homebrewing Computers in the 21st Century". Commodore Free (67).
  • Eliot (January 10, 2009). "N8VEM single board Z80 computer". Hack a Day.
  • Halfacree, Gareth (January 12, 2009). "The N8VEM eight-bit homebrew PC". Bit-tech.
  • Wimberly, Victoria (April 4, 2011). "Open-source Single-Board hardware and softwares".

External links

  • Retrobrew Computers (N8VEM project successor)
  • The Unofficial CP/M Web Site
  • John Monahan's S-100 board information site

March 03, 2023
n8vem, homebrew, computing, project, featured, variety, free, open, hardware, software, builders, made, their, homebrew, computer, systems, themselves, shared, their, experiences, with, other, homebrew, computer, hobbyists, homebrew, computer, components, made. N8VEM was a homebrew computing project It featured a variety of free and open hardware and software N8VEM builders made their own homebrew computer systems for themselves and shared their experiences with other homebrew computer hobbyists N8VEM homebrew computer components are made in the style of vintage computers of the mid to late 1970s and early 1980s using a mix of classic and modern technologies They are designed with ease of amateur assembly in mind In November 2015 the N8VEM project was ended by its creator Andrew Lynch and the community reconvened under the new name of Retrobrew Computers Contents 1 Creation and operation 2 Single board computers 3 ECB expansion peripherals 4 System software 5 References 6 Further reading 7 External linksCreation and operation EditThere are several N8VEM designs starting with a single board computer carrying a Z80 microprocessor designed to run CP M and similar operating systems It was created in 2008 by Andrew Lynch Contrasted with the P112 which has some surface mount components the N8VEM SBC uses only through hole components consistent with the design philosophy that building should be within the skills and resources of non professional hobbyists The project has also developed boards for other processors including Z180 Intel 80188 MOS 6502 Motorola 6809 68000 and 68030 The N8VEM boards are designed with the free KiCad Electronic design automation EDA toolset Printed circuit board routing provided by FreeRouting net Software is developed in Z80 8085 assembly language using the MS DOS Telemark Cross Assembler program TASM as well as the open source Small Device C Compiler A major design goal is to use freely available tools to the maximum extent possible The printed circuit board design is supplemented using component libraries available at KiCad Libraries specifically the Zilog Z80 CPU and Intel 8255 PPI chips The design philosophy encourages low cost development and assembly by hobbyist amateurs using common tools such as 25 watt soldering iron multimeter logic probe optional and common hand tools An oscilloscope is recommended but not required Some basic electronic skills are helpful although the printed circuit boards are designed for relative beginners There are numerous N8VEM components available including ECB 1 and S 100 backplane boards allow processor and expansion boards to be connected Other components include video boards disk controllers peripheral expansion and prototyping boards In response to interest from members the N8VEM homebrew computing project has collaborated in developing a range of boards for the S 100 bus These can be used to build new systems from scratch on that historic industry standard platform or to restore and enhance vintage S 100 systems preserved from the 1970s and 1980s Most of the S 100 board initial design work has been contributed by John Monahan of s100computers com with board layout prototyping and testing contributed by Andrew Lynch and other N8VEM supporters Some of these S 100 boards provide enhanced capabilities beyond what was available on original S 100 machines some are replacements for historic S 100 boards and other board projects aim to apply the convenient bus architecture to processor families beyond the 8080 Z80 CPUs for which the bus standard was originally designed notably 6502 68000 and later Intel processor types 2 N8VEM is notable for being the largest and most active homebrew computing community in existence today The project is entirely non commercial and is made up of over 350 hobbyists 3 4 many of whom are actively involved in designing and prototyping the hardware and software 5 The community is a modern day version of the historic Homebrew Computer Club frequented by Steve Wozniak and other pioneers of home computer development Printed circuit boards of the mature designs are manufactured in small batches on a collective order basis and distributed to members for the cost of the board manufacturing and shipping The project does not provide complete kits builders must procure their own parts to populate a board Support is purely on a volunteer basis through a Google Group and Wiki Software is open source and freely available for download from the Wiki The project was careful to keep things within the reach of the amateur computer hobbyist by using low cost and readily available components that can be assembled with simple hand tools In addition notable freeware system emulator SIMH 6 simulates the N8VEM SBC along with many other architectures providing a virtualised development environment that has the speed and flexibility of modern hardware Completed N8VEM hardware and software has frequently been displayed at Vintage Computer Festivals 7 8 Single board computers EditECB Bus SBC V2 Z80 UART PPI RAM with battery backup ROM RTC SBC 188 80C188 10 25 MHz UART PPI RAM with battery backup ROM RTC FDC N8 Home Computer Z8S180 33 MHz UART ROM RTC Dual Interrupt controllers Floppy SD Card 1MB RAM AY 3 8910 sound TMS9918A video ECB bus SBC Mark IV Z180 processor 512K SRAM 512K Flash or 1MB EPROM RTC SD Card 8 bit IDE RS 232 RS 422 ECB bus KISS 68030 68030 processor up to 32MHz up to 256M DRAM 32K SRAM 512K Flash ECB bus S 100 bus Z80 S 100 m68k S 100 In progress 8086 S 100 In progress 6502 6809 ECB carrier boards for other cpu s Other SBC6120 RBC A new edition of the Spare Time Gizmos SBC6120 Model 2 updated to use easily available RAM and EEPROM components only two PCB layers and KiCAD ECB expansion peripherals EditECB Backplane compact stand alone with 8 DIN 41612 slots ECB Bus Monitor single step address trap bus status Disk IO FDC amp IDE Parallel ATA drive expansion Zilog Peripherals CTC DART dual PIOs Video Display Unit 80 25 character mode video Prototyping board with IO decode buffered with labeled signal connectors ECB Extended backplane 12 slot with 3U mounting features DSKY monitor boot loader Hex LED display and keypad Sprites Color Graphics amp Sound TMS9918 AY 3 8910 joystick paddle interface Prop IO VGA PS 2 keyboard PS 2 mouse micro SD Secure Digital prototyping area Cassette Interface KCS audio cassettes 4MEM 4MB SRAM expansion for SBC 188 PPIDE SBC parallel expansion port IDE interface Juha SD SBC SD card for mass storage MSX Cartridge reader load contents of MSX cartridges MSX Cartridge 8K 16K amp 32K EPROMs µPD7220 V2 prototype 16 color video display RAM Floppy 4MB SRAM floppy drive replacement 4PIO 64 GPIO input output board ECB to Z80 socket adapter connect ECB boards directly to Z80 CPU 6x0x host processor Motorola 6800 MOS Technology 6502 CPU with ECB interface 6x0x IO mezzanine ACIA dual PIA PTC power and expansion bus interface 6x0x ECB backplane use ECB peripherals with stand alone 6x0x system There is an active community development forum N8VEM Google Discussion Group from which additional board designs have been developed There is active development of new boards underway System software EditRomWBW is a popular system software distribution written to execute on N8VEM hardware The N8VEM family of hardware are primarily Z80 based microprocessor single board computers as well as miscellaneous boards which may be combined and placed in an ECB like bus enabling the builder to create a custom computer system These computers are primarily built from discrete components as were computers in the late 1970s and 1980s The majority of the systems are Z80 based and use the CP M 80 operating system that was developed in the late 1970s by Digital Research Inc The RomWBW system software is highly configurable and supports all of the Z80 based systems constructed with N8VEM components The system software is entirely open source and is provided in both machine readable source form and as pre built images for those wishing to program firmware chips for insertion in the boards In addition to the fully implemented operating system with its BIOS customized for the N8VEM hardware there are several dozen utility programs that configure and verify the proper operation of system components such as persistent storage in the form of IDE Hard Drives Compact Flash and Secure Digital chips The CP M 80 BIOS is written in assembly language and is built using the TASM assembler Utility programs are written in a variety of languages including assembler Digital Research RMAC Aztec C and Digital Research PLI These natively hosted programming languages and tools such as WordStar a popular editor of the time execute under the CP M operating system and read source files stored on memory disk or persistent media such as IDE devices or Compact Flash and Secure Digital devices through the use of an external adapter The version 1 x distributions of the system software have been written in a very standard CP M 80 way and over the course of a half dozen releases has reached a highly stable state supporting the most commonly built configurations in use The version 2 x operating software was recently released and uses bank switched memory technology to achieve enhanced functionality Due to the new technology there are no practical limits on the number of drivers that can be built in In the future this will allow for dynamic configuration and will be much more flexible for the users in many ways similar to the CP M 80 Plus family of operating systems which also took advantage of memory paging In the same way the hardware is open source the software is provided in source form as well allowing users to both learn how software was written in the early days of microprocessors but also to write new software using provided tools and documentation available both in the distribution on the subversion server and downloadable from a variety of public archives worldwide The current owners of the Digital Research Inc operating systems and language software have licensed it for non commercial use and the most comprehensive archives can be found at http www cpm z80 de as well as other popular locations and mirrors An alternative system BIOS UNA BIOS also exists It has the advantage that a single ROM image can run on all Z80 and Z180 systems An alternative CP M implementation UNA CP M takes advantage of UNA BIOS disk and device drivers References Edit N8VEM Hd64180 ecb de Retrieved 2016 04 01 S100 Computers S100 Computers Retrieved 2016 04 01 Rich Cini s Computer Lab N8VEM SBC Classiccmp org 2016 02 20 Retrieved 2016 04 01 First Project N8VEM Single Board Computer Nathan s build log Thomasns wordpress com 2009 10 26 Retrieved 2016 04 01 N8VEM computer with a 3Km wireless link Hackaday 2009 03 04 Retrieved 2016 04 01 Altair Other Operating Systems Schorn ch Retrieved 2016 04 01 Vintage Computer Festival Vintage org Retrieved 2016 04 01 Finnegan Patrick 2010 09 18 N8VEM exhibit Flickr Photo Sharing Flickr Retrieved 2016 04 01 Further reading EditVermeulen Oscar Andrew Lynch July 2013 DIY Single Board Computers Part I Circuit Cellar 276 44 47 Wilson Mary June 2013 DIY Single Board Computers Circuit Cellar Vermeulen Oscar 2013 Homebrewing Computers in the 21st Century Commodore Free 67 Eliot January 10 2009 N8VEM single board Z80 computer Hack a Day Halfacree Gareth January 12 2009 The N8VEM eight bit homebrew PC Bit tech Wimberly Victoria April 4 2011 Open source Single Board hardware and softwares External links EditRetrobrew Computers N8VEM project successor The Unofficial CP M Web Site John Monahan s S 100 board information site Retrieved from https en wikipedia org w index php title N8VEM amp oldid 997544516, wikipedia, wiki, book, books, library,

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