EuroCard Bus Boards

The tables below summarize the boards created by RBC members using the Eurocard Bus (ECB).

Some of the processor cards can also function independently as Single Board Computers - a useful feature for users wishing to bootstrap a new ECB system. Check out the boards»sbc section for these.

Information related to the Eurocard bus is also listed below along with guidelines for input/output port configuration.

ECB Backplanes

Board NameDescription/Features
ECB Mini Backplane A 3-slot EuroCard Bus Backplane
Backplane-4 An 4-slot EuroCard Bus Backplane
Backplane-8 An 8-slot EuroCard Bus Backplane
Extended Backplane-12 A 12-slot EuroCard Bus Backplane
12-Slot Backplane for Siemens 505-6508 A 12-slot EuroCard Bus Backplane with a form factor specifically designed to fit in a readily available Siemens 505-6508 chassis box

ECB Processor Boards

Board Name Description/Features
KISS-68030 A Motorola 68030 processor board. Requires the Multifunction Controller (MF/PIC) board for I/O (see below). DRAM memory up to 256Mb. Linux runs in 32Mb.
Mini-M68K A Motorola 68008 processor board. Requires the Multifunction Controller (MF/PIC) board for I/O (see below). Runs CP/M-68.
SBC-188 An Intel/AMD 80C188 processor board. Capable of functioning both as an an SBC and on the ECB bus. Currently (Jan-2020) undergoing a re-spin to up the on-board SRAM to 1Mb; i.e., 640K to the DOS user.
Mark IV A Zilog Z180 processor board. Capable of functioning both as an an SBC and on the ECB bus. SDcard & IDE-8 (for CF card) interfaces on-board.
SBC V2 A Zilog Z80 processor board. Capable of functioning both as an an SBC and on the ECB bus.
6x0x-ATX-6U An MOS 6502 / Motorola 6809 processor board. Electrically capable of functioning both as an an SBC and on the ECB bus, but ECB software support currently limited
N8 A Zilog Z180 processor board. Electrically capable of functioning both as an an SBC and on the ECB bus, but ECB software support currently limited
SBC-386EX Intel 80386EX processor board with 80387 coprocessor option.

ECB Input/Output/Memory Cards

Board Name Description/Features
PropIO A Propeller-based I/O board that provides keyboard, video, and SD Card storage.
4PIO The ECB-4PIO board contains 4 Z80A-PIO and the complete Bus-Control-Logic for the ECB-Systembus conform to KONTRON
ModPrn ECB-PCB to communicate with SBC V1, SBC V2 or any other developed Z80-CPU to outside the Computer system (Serial communication, Communication via Modem) or to use serial Printers with RS232/V.24-Interface
RamFloppy A RAM Floppy does not use the local memory resources of the processor, but instead is implemented as an external storage subsystem, which may functionally appear as being similar to a floppy or modest hard drive.
Color VDU A traditional video display board with color capability. Provides 80×25 text and will drive VGA displays that are capable of EGA display frequencies. Also includes a keyboard and mouse interface.
VDU Monochrome 80×24 video card.
VGA3 80×25 or 80×30 text display; operates at VGA frequencies to operate on a greater number of displays than the CVDU (above). Fonts are programmable. Includes an IBM PS/2 keyboard interface. Operates memory-mapped (for SBC-188 MS-DOS), or registered access (similar to CVDU).
Dual SD Card A board providing Dual SD Card storage
DiskIO V3 A board providing floppy and IDE storage support
MF/PIC Multifunction Programmable Interrupt Controller support board required by the ECB Mini-68K CPU and ECB KISS-68030 CPU boards. It may also be used with the SBC v2 (Z80) to provide mode 2 interrupt vectoring.
2S1P Multifunction serial/parallel card with two RS-232 serial ports and one Centronics/EPP AT-compatible parallel printer port. Designed primarily for use with the SBC-188 CPU-based system, but can be used with others.
SCSI SCSI peripheral interface using the NCR5380 interface chip. Requires the use of a DMA board or CPU with DMA capabilities.
4MEM 4MB expanded memory board for SBC-188. Uses EMM4MEM.sys driver. Also expands SBC-188 memory to full 640K. Expanded memory is good for a battery-backed Ramdisk.
4UART Quad high-speed UART interfaces to RS-232 or USB at up to 3Mbps. 2 ports are dedicated to USB; 2 ports are USB or RS-232, selectable.
ADIO An Analog/Digital I/O Board
DSKY A Display Keyboard unit providing a hexadecimal display and numeric input keypad.
Cassette Interface Allows for storage/retrial of files on cassette tapes using the Kansas City Standard
USB FIFO A EuroCard Bus board providing a fast interface between ECB machines and modern PCs over USB.
SCG The “Sprite Color Graphics” is an ECB video display board based on the TMS9918 which features color graphics and sprite management. Board also includes AY-3-8910 sound support and dual joystick support.

ECB Accessory Cards

Board Name Description/Features
Bus Monitor Card with “blinkenlights” for monitoring the ECB bus and single-stepping the CPU.
Bus Extender Extension card which allows for ECB cards to be height-extended out of the chassis for easier debugging.
Prototyper C'T Projekt ECB bus prototyping card from C'T Projekt article.
Prototype w/I/O Decode ECB bus prototyping card with I/O Decode.

"Orphaned" ECB Cards

These are ECB cards which:

  1. Have no KiCAD or Gerber files available on the wiki
  2. Have no community member listed as a board distributor on the RetroBrew Computers Board Inventory page

These board could be “brought back” if KiCAD/Gerber files are located, or if someone is willing to re-enter the schematic into KiCAD and re-route a new board.

Board Name Description/Features
Active Termination A board which provides Active Termination to the ECB bus

Retired ECB Cards

Retired ECB Cards - .zip file archives with old information on cards which have been intentionally retired or superseded.

ECB Board I/O Port Guidelines

BoardPortsFixed PortNotesDIN 41612 B rowReset Support
4MEM boards x 400..07N ADDRESSLEGACY
IDE & Floppy Controllers (DISK I/O, Dual IDE)20..3F
Z180 Mark IV internal registers40..7FY N/A
N8 Home Computer internal registers40..7FY
MF/PIC40..4FNHas also been at 80..8F LEGACY & KONTRON
SBC V2 on-board peripherals60..7FY NOT USEDLEGACY & KONTRON
Z180 Mark IV on board peripherals80..8FY
N8 Home Computer on board peripherals80..9F
SCG graphics (including AY-3-8910 sound)98..9FNSame as N8NOT USEDLEGACY & SOFTWARE
RAM-Floppy x 2A0..A7NBoard 1 A0-A3 Board 2 A4-A7NOT USEDLEGACY & KONTRON
Zilog peripheralsB0..BFNLEGACY only on V1 board.NOT USEDLEGACY & KONTRON
Prop I/OA8..AF
ReservedF0..FF For experimental boards
VDU (including Keyboard, Mouse and printer port)F0..F7Y NOT USEDLEGACY

EuroCard Bus

(This page is still current as of 29-Nov-2019. –jrc)

Pin assignments as of 19-Nov-2014. This represents all ECB boards from the ECB SBC v1 (Z80) to the ECB M68030 CPU board.


RetroBrew ECB bus evolution

The graphics in this folder document the evolution of the RetroBrew ECB bus as it has expanded from the original SBC v1 (Z80) to the present usage. (ECB-06.jpg is the most current.)

The basis for the RetroBrew bus was the Kontron (a German firm) bus for the Z80 microprocessor. The signals on the original bus were Z80 specific and were confined to the A & C rows of pins on the 96-pin connector. Kontron defined a number of additional signals in planning for the bus to be expanded beyond the Z80 microprocessor. Additional signals included mainly VBAT, for battery backup power. Specifically absent from the RetroBrew bus are the +12v, -12v, +15v/12v, and -15v/-12v power supplies. RetroBrew by intent uses only +5v power. RS-232 voltage levels are obtained by using the voltage doubler / inverter in the MAX232 interface chip.

The first serious expansion of the RetroBrew ECB bus came with the SBC-188, a card utilizing the Intel 80C188 processor. The data bus remained 8-bit, but the address bus was expanded by 4 bits from 16 to 20 bits: B_A0 to B_A19. Other Intel signals, deemed to have future utility, were also defined. Most notable were: B_DT/R (data transmit / receive), B_/INTA (interrupt acknowledge), B_/DREQ (DMA request), and B_/DACK (DMA acknowledge).

The vectored interrupt lines were defined by the SBC v1, but never used until the introduction of the Multi-Function / Programmable Interrupt Controller (MF/PIC) board. This board, which can be programmed to operate with SBC v1, SBC v2, and the mini-M68000 CPU board, expands the interrupt capability of any processor to 8 prioritized interrupt requests. The CPU's which utilize the controller are able to vector the incoming interrupts. These input signals, /IR0 to /IR7, high to low priority, are on the B pin row.

The Motorola 68000 uses 24 address lines and 16 data lines. The Mini-M68k board uses a version of the 68000 with 8 data lines and only 22 address lines. However, in anticipation of a full 68000 CPU board, the mini-M68k defines the position of 4 additional address bits – and drives all of them: B_A20 to B_A23. There were a couple of different assignments of these address lines to pins, and the choice was made to keep the address bits on the A and C pin rows only. The future expansion of the data bus to 16-bits places D8 to D15 on the B row. Between ECB-03.jpg and ECB-04.jpg, the order of these data signals on the B row has been reversed to agree with existing Kontron documents. Likewise, signals /DS0 and /DS1 (Data Select) are added, and /SXTRQ and /SXTAK (sixteen bit Request / Acknowledge) have been added. Exact usage of the last two will probably be similar to S-100 usage, and for now, should be treated as “TBD.”

–John Coffman

ECB bus history

The German firm Kontron defined what is believed to be the earliest bus using the 96-pin DIN 41612 EuroCard connectors. The bus for their Z80 offering used only the A-row and C-row pins; the B-row was left entirely unused to allow for the use of 64-pin connectors in the 96-pin format.

The earliest known RetroBrew bus definition added B-row pin definitions in anticipation of expansion of the Z80 bus to other processors, notably Intel. To this day, the ECB SBC v2 (Z80) does not use the B-row pins.

One error occurred in defining the first RetroBrew bus: confusion between signals RESET (C-31) and RESOUT (C-26). The error resulted in a bad guess at what Kontron's intentions were with these two signals. SBC v1 (Z80) used RESET as an output from the CPU board to peripheral boards, and did not use the RESOUT signal at all. Peripheral boards were designed with this assumption. When it was pointed out several years ago (I am unsure of the date) that Kontron's intention was for RESET to be an input to the CPU board only, and that the CPU board would then put out a signal, RESOUT, to all of the peripheral boards in the system.

The resolution to the above mistake is that all the newer CPU and Peripheral boards have a reset selection jumper to select which RetroBrew reset convention is to be used. Look for a 3-pin jumper header: shorting pins 1-2 indicates the older, erroneous, reset convention for use with older boards; shorting pins 2-3 indicates the use of the Kontron convention. The Kontron convention is required if RESET is to be input from any of the ECB backplanes, and only newer board may be used in such a system. Old CPU boards have a 2-pin Reset (in) connection as well as a Reset switch right on the CPU card.











ECB-06.jpg – 19-Nov-2014 (32 address lines, 16 data lines)


***Note: The M68030 board drives 32 address lines; however, it does not, at this time transfer 16-bit data. It accesses older peripheral boards with 8-bit data.

John Coffman – page created 24-Feb-2016

boards/ecb/start.txt · Last modified: 2020/01/07 08:40 by b1ackmai1er
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