White Rabbit Switch Fan-less hardware
Project description
White Rabbit Switch is the central element of a White Rabbit network and was designed as a part of the White Rabbit project. The current version of WRS 3.4 is built with two fans to provide force air cooling. Measurement shows that when the fans fail, temperature inside the WRS increases significantly, especially the FPGA chip.
WRS-Fan-less is a fan-less version of the WRS, specifically designed for long-term service-less operation and originated at the LHAASO project.
It is an open hardware design of an 18-ports Ethernet switch licensed under CERN OHL 1.2. As the design is open it can also be used as the hardware platform for other, non-White Rabbit projects.
Original WR Switch v3.3 top view of PCBs. The fan-less version will
have a different, larger, board on the left and no fans in the back*
Main Features
In bold the features that are different from WRS-3.4
- Front Panel
- 5 SMA connectors ****
- 1-PPS input
- 1-PPS output
- 62.5 MHz output
- 10 MHz output (software configurable)
- 10 MHz input
- 18 cages for Gigabit SFP transceivers (connected to Xilinx GTXs)
- 10/100 Ethernet management port (connected to ARM CPU) on SFP (was RJ-45 used on WRS-3.4)
- USB port (connected to ARM CPU)
- 2x USB-uart debugging port (connected to ARM CPU and FPGA I/O pins) (was on back panel on WRS-3.4)
- Power and Status LEDs
- Link and Act LEDs for each SFP cage
- 5 SMA connectors ****
- Back Panel
-
2x USB-uart debugging port (connected to ARM CPU and FPGA I/O pins)move to front panel - power button
-
2x cooling fanremoved in WRS_FL -
2x microswitchremoved in WRS_FL - 1x grounding connector
-
- Xilinx Virtex-6 FPGA (XC6VLX240T)
-
18Mb QDRII memory (CY7C1314KV18)not mounted in WRS_v3.4, removed in WRS_FL -
256Mb parallel configuration memory (PC28F256)not mounted in WRS_v3.4, removed in WRS_FL
-
- Clocking resources
- Integrated Low-jitter WRS daughterboard for improved clock outputs
- VM53S3-25.00 as default Internal Oscillator
- T604-025.0M, IVT32000C,DOT050V-020.0M, CVHD-950-100.000 can be mounted for evaluation.
- refer to SCB_clock_tree
- ARM Atmel AT91 SAM9G45 CPU
- Memory:
- 64MB DDR2
- 256MB NAND
- 8MB boot flash
- Others:
- 1x FPGA JTAG connector
- 1x ARM JTAG connector
- 1x SYS_ADMIN header (orignial P10 on WRS_3.4, with manual reset signals)
- 1x UART & PWR_Mon header (original P2 on WRS_3.4, with additional USB-UART and Power signals)
- 2x QSS/QSH high speed connectors between SCB and backplane
- 4x Ultra Small Surface Mount Male Coaxial Connectors for clock circuit test
-
1x QSS-016 high speed SMI link connectornot mounted in WRS_v3.4, removed in WRS_FL -
1x gold-finger uTCA edge connectorremoved in WRS_FL
- Power supply 100-240VAC, 2.0A, 50-60Hz input, 12V DC, 6.66A, 80W output
- Box dimensions 482.8 x 42.34 x 222 mm
- Certification (TBD)
- IPC-610 Rev E Class 2
- ISO-9001
- ISO-14001
- CE
- RoHS
- CCC (China Compulsory Certification)
WRSwitch fan-less hardware consists of three elements:
- “main SCB PCB”:https://www.ohwr.org/project/wrs-fl-hw/wikis/wrs-fl-hw-scb - contains main electronics components, ARM processor, Xilinx FPGA chip, oscillators, memories, etc. - This is a redesigned board, different from the one used in the original WRS-3.4.
- backplane PCB - electrical connections to 18 SFP cages, debug USB-uart ports, LEDs, etc. - This board is redesigned for different panel arrangement.
- WR Switch Box - is a 19'' 1U case. There are no cooling fans in the back - This box is specifically designed for passive cooling. The panel arrangement is different from WRS-3.4.
backplane board
mechanical box
heat disipation
Without cooling fan, conduction cooling is built very similar to the ITX
fanless computer (as shown in
example).
Cooling components of ITX fanless computer*
The SCB is covered by aluminum block with spaces milled for large components, remaining height difference will be covered by thermal pad or glue. With another upper block to clamp two heatpipes in between. The heat pipe is twisted to reach another heat block that attached on the bottom* side of the box. Heat from the components finally conducted to the box. In the ideal situation, the 25Watt of the WRS will spread over the whole surface of the box, which then actually attached to a rack via which it is also constructively cooled.
Project information
- Production documentation
-
Gateware for WR Switch
- compatible to WRS-3.4
-
Software for WR Switch
- compatible to WRS-3.4
- Frequently Asked Questions
Releases
Users List
LHAASO (Large High Altitude Air Shower Observatory)
Contacts
Commercial producers
- Will be commercially available by SyncTech - a spinoff company from THU.
General question about project
- Guanghua Gong - Tsinghua University, Beijing
Status
Date | Event |
21-02-2018 | Start of project |
2 March 2018