IGreplane

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IGreplane board.png

Rational

As a matter of general coherence and re-usability, it is often desirable to specify common frame or pattern for the different boards embedded in a robot. For example, it could be as simple as specifying a board size and its related mechanical holes positions. Thus, by using such a constraint in the different electronics board developments, it allows fully parallel and independent works regarding the mechanical aspects.


Since IGrebot uses a common bus, it is also very convenient to specify at the same time the logic interfaces between the different boards. By combinating mechanical and interfaces specifications, it is then possible to develop an "aggregation" board which literally hosts all our electronic guys.


With our backplane board (IGreplane) we want to match those specific points:

  • Fully re-usabilility and board-independant (i.e. do not depend on specific boards considerations)
  • Carry the main digital interface (CAN bus) and the different power-supplies
  • Must allow a certain flexibility in the boards size and I/O constraints
  • Should also be as small as required since professional PCB services are expensive and space is limited


The next section describes the IGreplane specifications, used as a background spec for all electronics developments.

Specifications

Backplane layout

...To be updated... File:2014_backplane_layout.png|600px

  • The white rectangle at the connector's top represent the HE-10 slot
  • The board's HE-10 connectors are female
  • The green line represent a double size board and its position when slotted into the backplane
  • The four grey dots represent the Igreplane board holes located in each corner at 5mm from both edges and with a diameter of 5mm


Backplane connector

2014 backplane connector pinout.png

Conventions

  • VSS* : Negative rail of power supply
  • VDD* : Positive rail of power supply
  • *N : Indicates a digital signal active low


Parts references

Female header for backbone

Manufacturer: WUERTH ELEKTRONIK 						
Serie: WR-PHD						
Description: 2.54MM DUAL S. HEADER BOTTOM ENTRY LARGE, 26 WAYS						
Manufacturer ref. 613026216921						
Farnell ref. None						


Angled male header for boards

Manufacturer: WUERTH ELEKTRONIK 						
Serie: WR-BHD						
Description: 2.54MM MALE ANGLED BOX HEADER, 26 WAYS					
Manufacturer ref. 61202621721					
Farnell ref. 1642026


Boards specifications

2014 backplane boards.png


  • Boards are viewed from the top, if a specific mention (TOP) or (BOT) appears, the dedicated area is only present on the referenced side.
  • Usage of 1 or 2 specific backplane connector (see references on dedicated tab)
  • The grey dots represent on each board 4 holes, diameter of 3 mm, placed at 3 mm of the board's edges, in each corner.
  • Each board shall embed a dedicated 4 way DIP switch that allows to set its ID for bootload or address operations (this switch might also be “solder-bridged” directly)
  • In case of space for I/O connectors, it is recommended to place them as close as possible to the boards edges and its I/O zone(s) in order to facilitate the board's “plug'n playibility”

Boards assignation

# L R
1 IGrebrain
2
3 IGrevator
4 IGresive
5 IGresupply 1/2
6 IGresupply 2/2

Power-supplies repartition

TBD.

Realization

PCB Design

IGreplane PCB.png

IGreplane 3D gerber.png

IGreplane board.png