Table of Contents
ECB Mini Backplane
Introduction
The ECB Mini Backplane is a backplane card for the EuroCard Bus which allows up to 3 ECB cards to be connected at one time.
The backplane features a power input, power switch, LED to indicate when power is on, and a 2-pin input header to connect a reset switch. On the back side of the PCB the ECB pin rows and columns are labeled for quick identification, and a key listing the ECB signal names is provided.
The reset input header is connected to pin C31 for Kontron compatible reset (which is recommended over the legacy “N8” style reset).
The board is designed to be used either flat on a table with the cards standing up, or on its side with the backplane connectors and power switch above the ECB cards and both backplane and cards resting their edges on the table.
The 2018 PCBs are manufactured using 1.6mm thick FR4 with lead solder HASL finish (the 2017 boards used 2.0mm thick FR4 with ENIG finish, however HASL is nicer to solder, 1.6mm is easily strong enough, and it reduces the cost significantly)
Schematic
Bill of Materials
| Component | Description | Example Part |
|---|---|---|
| RESET | 2-pin 0.1“ Header | TE Connectivity part 5-826629-0: 50 contact breakaway header strip (Farnell order code 3418388) |
| LED | Standard 5mm LED (20mA) | Lite-On LTL-4233 (Mouser order code 859-LTL-4233) |
| POWER SW | SPDT Toggle Switch, ON-ON type, 0.185” lead spacing, 5A rating | TE Connectivity A101SYCQ04 (Mouser order code 506-A101SYCQ04) |
| POWER IN | 4-pin disk drive power connector | Molex 15-24-4745 (Farnell order code 1391827) |
| U1, U2, U3 | DIN 41612 Connector, Type C Socket, 96 contacts | TE Connectivity 5535043-5 (Mouser order code 571-5535043-5), or 535090 which has shorter pins |
| C1, C2, C6, C7 | Capacitor with 0.2“ lead spacing, under 10mm diameter, under 12mm height (Builder's choice - typically at least 100uF) | Panasonic 6SEPC560MX (good diameter, lead spacing is a bit narrow but fits with some “encouragement”, very low ESR) Panasonic EEUFR1E331B (untested but looks to be a good choice) |
| R1 | 470 ohm 0.25W resistor | Multicomp MCF 0.25W 470R (Farnell order code 9339531) |
Notes on Construction
Make sure you fit the ECB sockets the correct way round! See the photographs if unsure.
The power switch is optional and can be omitted simply by fitting a (reasonably thick) wire jumper in its place.
Ensure any electrolytic capacitors are fitted observing the correct polarity (as marked on the board). Choose capacitors small enough not to interfere with ECB card insertion.
If you will be using the Interrupt or DMA chains you will need to fit four wire jumpers connecting /BAO to /BAI and /IEO to /IEI as indicated on the PCB. The only Retrobrew Computers board to use these signals is the “Zilog Peripherals” board so these jumpers can generally be omitted.
If you intend to use the board lying flat with the cards standing up, fit four 3M BumpOn rubber domes on the rear to prevent scratching your work surfaces. If you intend to use the board vertically with the ECB cards lying against the desk be aware that many cards will be “upside-down”, so please take care to ensure the electrons don't fall out.
Photographs
Curt Mayer (curt@zen-room.org) has published a 3d printable card cage for this motherboard.
it can be downloaded from https://github.com/cm68/ecb_cage_3
