StaRFIshrail Hub

The Hub is the heart of the system, communicating with all your readers, and other busses and your control computer.

Hub DC input Connector

The dc which powers the hub and all the readers is connected via this socket.  The power supply should be between 12V and 18V dc, and should be rated at 24W - which roughly translates to 2A at 12V, or 1.5A at 18V.  The power supply socket is a 2.1mm/5.5mm round connector, with centre pin positive.  The dc input is reverse polarity protected.  If you are not using the supply from StaRFIshrail, please carefully check the specification of the power supply - more than 20V can do permanent damage to the Hub and any readers plugged in.  When the dc is plugged in, the green LEDs VIN, 4V5 and 3V3 should light, indicating there is power on the board.  The green LED on each connected reader board should also light.  The red LED "RUN" should also flash at approximately half second intervals, - if this LED is either on, or off, of flashing very slowly, then the board may need re-programming - see Programming page in the Technology section.

Hub Port Connections

There are 8 vertical RJ45 connectors, each of which can communicate with up to 4 RFID points, giving a total of 32 RFID points per hub. Each RJ45 can communicate with the following:
1 Quad Reader
1 or 2 Dual Readers
1 or 2 or 3 or 4 Single Readers
1 Dual Reader and 1 or 2 Single Readers.
The readers can be placed in any order in a daisy chain, but it is up to you to make sure that there is no address overlap (see readers).  The ports are clearly marked on the board (1-4, 5-8 etc), and these map directly to addresses in the data going to the control computer.  You should also use colour-coded RJ45 cables, or labelled cables, to make sure that things do not get muddled if you need to disconnect cables.  Cables are available from the StaRFIshrail store.

Ethernet Connector

The Ethernet connector is for connecting to your computer system.  The Ethernet can either be connected directly, or fed through a hub, or fed into a wireless hub.  The Ethernet is fixed at 100M - Cat5 or Cat5e cable should be used for connection, but you should be able to use up to 50 metres of suitable cable with no problem.  The MAC (Media Access Control) address is printed on a label, and this is unique to each hub.  You will need this address when setting up the Ethernet IP address. 


CBUS is an open standard, and is used for connecting control boards together.  The CBUS connector is a 3 pin 3.5mm pluggable connector, with GND, H and L signals.  Most CBUS boards take their power from a power bus, and consequently have 4 pin connectors, but due to the amount of power that the StaRFIshrail Hub needs, the dc and the CBUS have been separated.  There is a linkable 120 ohm termination resistor on the board - if you need to terminate the bus at the hub, then place the link between the two pins at the end of the 5 pin strip marked "TERM", otherwise either remove the link and keep it safe, or place it between the centre pin of the 5 pin connector and either adjacent pin.  There is also a programming switch, and two LEDs, the green one marked "S" for SLim, and the yellow one marked "F" for FLim.  These work in the classic MERG style, and further information can be found in the Installation instructions.  SLim (green LED on) is the factory default.  The matching 3 pin plug is included with the Hub.

Address switch

This is a 16 position hex switch, marked 0-9 and A-F (representing 10-15). The switch is small, and should be operated with a small flatbladed screwdriver, such as a watchmakers screwdriver.  This switch sets the address of the hub - if you have more than one hub in a system they should be set to different addresses.

Option switch

This switch enables different options to be enabled on the hub. Like the Address switch, this is a 16 position Hex switch. Operating modes are 0-9 and A-E.  Option F is reserved for programming, and the hub should only be put into this mode when re-programming, or setting Ethernet addresses - this is to prevent accidental settings.

Flim/Slim Mode

The Hub can be operated in Flim or Slim mode, as with standard MERG modules.  The mode will be remembered over a power down, and changing modes is done by pressing and holding the FLim/SLim switch.  The Flim LED (marked F) is orange, and the SLim LED is green, as per MERG usage.  As the Hub is a producer only module, the available controls via the FCU program is limited to setting the Node Number, and hence the DDES number.  These modes act in conjunction with the address switch.


This connector is a micro B USB type.  This is used for serial communication with a computer, and uses a FT234X chip.  When plugging this in for the first time to your computer, the driver should be automatically found by the computer.  The USB is used for re-programming, but can also be used for transferring data in and out of the hub.  A micro B USB to type A USB cable is available in the StaRFIshrail store.

Reboot switch and REC link

The hub firmware and software can be re-programmed via the USB port.  It is possible, however, for this to go wrong, or for the processor or Xilinx to loose their memory, possibly as the result of accidental static discharge, or an unexpected power supply surge.  If the hub no longer works, i.e. the RUN light is not flashing at 1/2 second intervals, then the first course of action is to press the Reboot switch, which will start the Xilinx and processor from scratch.  If this does not cure the problem, then the Xilinx may be put into a factory reset mode, by putting the 0.1" link between the "REC" pins, and then rebooting.  This actually reboots the Xilinx from a fully protected memory chip, and after this, then latest Xilinx code and software can be uploaded.  Please see programming in the Installation pages for more details.

Operating LEDs

There are 10 LEDs on the board, together with a LED in the Ethernet socket.  These give you basic information on what is happening on the hub.
1]  VIN  Green - lights when dc input is present, should always be lit
2]  4V5  Green - lights when the 4.5V supply is present, should always be lit
3]  3V3 Green - lights when the 3.3V supply is present, should always be lit
4]  RUN Red - Debug LED for firmware and software
Flashes at 1/2 second intervals - all in correct
Flashes at 2 second intervals - firmware OK, software not running
On or off - firmware not running
5]  USB - Yellow - flashes when data is present of the USB lines
6]  ETH - Yellow - Ethernet Status (same as on ethernet socket)
On - Ethernet connected
Off - Ethernet not connected
Blinking - Ethernet data being sent or received
7]  CBUS - Yellow -  Blinks when CBus data being received
8]  S - Green - hub in SLim mode
9]  F - Yellow - hub in FLim mode
10]  RFID - Red - RFID reads taking place successfully    

How the Hub works

The hub is based around a Xilinx FPGA (Field Programmable Gate Array) and an Atmel processor. In addition, there is an Ethernet interface chip, a USB interface chip, a CAN interface chip, and multiple FETs for interfacing to the readers. There are switched mode power supplies, memory chips, switches, LEDs, an oscillator, a linear supply, and reverse voltage protection. For those interested in a more detailed explanation of how the hub works, a pdf can be downloaded here.