Europe Card Bus
Encyclopedia
Europe Card Bus
The Europe Card Bus (ECB or ECB-bus) is a computer bus developed in 1977 by the company KontronKontron
Kontron AG is a German-based multinational company which designs and manufactures embedded computer modules, boards and systems.Kontron AG serves OEMs, system integrators and application providers of different market segments...
, mainly for the 8-bit Zilog Z80
Zilog Z80
The Zilog Z80 is an 8-bit microprocessor designed by Zilog and sold from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes...
, Intel 8080
Intel 8080
The Intel 8080 was the second 8-bit microprocessor designed and manufactured by Intel and was released in April 1974. It was an extended and enhanced variant of the earlier 8008 design, although without binary compatibility...
and Intel 8085
Intel 8085
The Intel 8085 is an 8-bit microprocessor introduced by Intel in 1977. It was binary-compatible with the more-famous Intel 8080 but required less supporting hardware, thus allowing simpler and less expensive microcomputer systems to be built....
microprocessor
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...
families.
Physical format
Mechanically, the ECB is usually implemented as a backplaneBackplane
A backplane is a group of connectors connected in parallel with each other, so that each pin of each connector is linked to the same relative pin of all the other connectors forming a computer bus. It is used as a backbone to connect several printed circuit boards together to make up a complete...
circuit board installed in a 19-inch rack
19-inch rack
A 19-inch rack is a standardized frame or enclosure for mounting multiple equipment modules. Each module has a front panel that is wide, including edges or ears that protrude on each side which allow the module to be fastened to the rack frame with screws.-Overview and history:Equipment designed...
chassis.
ECB cards have 3U Eurocard format (100 mm × 160 mm).
Connector
Use two or three-row versions of DIN 41612DIN 41612
DIN 41612 is a DIN standard for electrical connectors that are widely used in rack based electrical systems. Standardisation of the connectors is a pre-requisite for open systems, where users expect components from different suppliers to operate together. The mostly widely known use of DIN 41612...
connectors, 0.1" pitch. Original Kontron ECB, supported 64 pins, using "a" and "c" rows, ”b” row tied to "C' row.
ECB boards are NOT compatible with STEbus or VMEbus P2 connector (while STEbus does not use the “b” column; VME does define specific signals on the ‘b’ row).
Pinout
| num. | name | a b c | name |
|---|---|---|---|
| 1 | +5V | o + o | +5V |
| 2 | D5 | o + o | D0 |
| 3 | D6 | o + o | D7 |
| 4 | D3 | o + o | D2 |
| 5 | D4 | o + o | A0 |
| 6 | A2 | o + o | A3 |
| 7 | A4 | o + o | A1 |
| 8 | A5 | o + o | A8 |
| 9 | A6 | o + o | A7 |
| 10 | WAIT/ | o + o | D8 |
| 11 | BUSRQ/ | o + o | IEI |
| 12 | BAI 1 | o + o | D9 |
| 13 | +12V | o + o | D10 |
| 14 | D11 | o + o | D1 |
| 15 | -5V | o + o | -15V |
| 16 | 2PHI | o + o | IEO |
| 17 | BA0 1 | o + o | A11 |
| 18 | A14 | o + o | A10 |
| 19 | +15V | o + o | D13 |
| 20 | M1/ | o + o | /NMI |
| 21 | D14 | o + o | INT/ |
| 22 | D15 | o + o | WR/ |
| 23 | /DPR | o + o | D12 |
| 24 | +5VBat | o + o | RD/ |
| 25 | nPHI | o + o | HALT/ |
| 26 | WRITE EN | o + o | /PWRRCL |
| 27 | IORQ/ | o + o | A12 |
| 28 | RFSH/ | o + o | A15 |
| 29 | A13 | o + o | PHI |
| 30 | A9 | o + o | MREQ/ |
| 31 | BUSAK/ | o + o | RESET/ |
| 32 | GND | o + o | GND |
Active low signals indicated by asterisk.
GND: Ground reference voltage
+5V: Powers most logic.
+12V; -12V: +15V; -15V
Legacy power inputs, primarily useful for RS232 buffer power or ADU. The +12V used for programming voltage generators. Both can be used in analogue circuitry, but note that these are primarily power rails for digital circuitry, so decoupling or local regulation is recommended for analogue circuitry.
+5VBat: Standby voltage. Optional.
This line is reserved for carrying a battery backup voltage to boards that supply or consume it. NiCad batteries are common source. The ECBbus spec is not rigid about where this should be sourced from. In practice, this means that most boards requiring backup power tend to play safe and have a battery on board, often with a link to allow it to supply or accept power from +5VBat . You can end up with more batteries in your system than you need, so care must be taken that no more than one battery is driving the +5VBat line.
D0...7: Data bus.
This is only 8-bits wide, but most I/O or memory-mapped peripherals are byte-oriented.
A0...19: Address bus.
This allows up to 1 MByte of memory to be addressed. Current technology is such that processor requiring large amounts of memory has this on the processor board, so this is not a great limitation. I/O space is limited to 4K, to simplify I/O address decoding to a practical level. A 74LS688 can decode A11...4 to locate I/O slave boards at 16-byte boundaries.
BUSRQ/ and BUSAK/: Bus Requests and Bus Acknowledge. Optional, used by multi-master systems.
The number of Attention Requests reflects that the ECB-bus aims to be simple.
Single-master systems are the norm, but these signals allow systems to have secondary bus masters if needed.
HALT/: CPU Stopped.
BAI 1; BAO 1: Bus Priority In; Bus Priority Out.
IEI; IEO: Interrupt Enable In; Interrupt Enable Out.
IORQ/: In / Out Request
PHI; nPHI: System Clock; nx Clock.
MREQ/; RESET/ : Memory Reset; System Reset.
Technical notes
- Signal inputs must be Schmitt trigger.
- Signal outputs must have a fan-out of 20
- Backplane can have up to ?? sockets
- Active bus-termination recommended
Notable uses
N8VEMN8VEM
N8VEM is a homebrew computing project. It features a variety of free and open hardware and software. N8VEM builders make their own homebrew computer systems for themselves and share their experiences with other homebrew computer hobbyists...
homebrew computing project uses ECB
Europe Card Bus
- Europe Card Bus :The Europe Card Bus is a computer bus developed in 1977 by the company Kontron, mainly for the 8-bit Zilog Z80, Intel 8080 and Intel 8085 microprocessor families.-Physical format:...
and provides a large number of various ECB cards and a couple of ECB backplanes.