ROACH-2 Revision 2

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The official ROACH logo.

ROACH-2 is a stand-alone FPGA board and is the successor to the original ROACH board. ROACH stands for Reconfigurable Open Architecture Computing Hardware.

Contents

Background

ROACH-2 was designed as the sequel to ROACH-1 using the new Xilinx Virtex-6 series of FPGAs. It maintains all the aspects that made ROACH-1 a success, but increases the overall performance in terms of processing power, IO throughput and memory bandwidth. It uses the same PowerPC 440EPx present on the ROACH-1 but adds a unified JTAG interface provided through an FTDI FT4232H IC.

Design Features

Closer look at the V6

The ROACH-2 design includes the following notable features:

  • Virtex-6 SX475T FPGA (XC6VSX475T-1FFG1759C)
  • PowerPC 440EPx stand-alone processor to provide control functions
  • 2 x Multi-gigabit transceiver break out card slots, supporting up to 8x10Ge links which may be CX4 or SFP+
  • 4 x 36 * 2M QDR II+ SRAMs connected to the FPGA
  • A single 72-bit DDR3 RDIMM slot connected to the FPGA
  • 2 x ZDOKs
  • An FTDI FT4232H USB to JTAG, serial and IIC

Block Diagram

The current block diagram is shown below:

Current Block Diagram

Project Status

The first prototypes have been assembled and are currently being tested.

Github repository

A Github repository is used to host all the ROACH-2 design files.

Schematics

You can find the final revision 2 (the third prototype) schematics at: https://github.com/ska-sa/roach2_hardware/blob/master/release/rev2/A/ASSEMBLY/roach2_rev2_schematics.pdf

Design Files

You can find all the design files for the first prototype, including gerbers, at: https://github.com/ska-sa/roach2_hardware/tree/master/release/rev2/A

The roach2.PcbDoc and various schematics files like qdr0_1.SchDoc may be viewed on Windows computers using Altium's free viewer found at http://www.altium.com/community/downloads/en/downloads_home.cfm specifically the 131 MB file at http://downloads.altium.com/altiumdesigner/AltiumDesignerViewerBuild9.3.0.19153.zip No registration is required and installation is simple.

Design

ROACH-2 was primarily specified for the packetised correlator, which was considered to be the most demanding application. A number of configurations were considered, including PAPER, ATA and MeerKAT's upcoming requirements. The calculations for memory sizing, datarates and bus widths can be found here.

The ROACH-2 REV 2 Prototype Boards went into production in August 2012 and include modifications intended to address some of the issues encountered in the previous revision.

These modifications include :

  • Isolation of the 3V3 and 3V3Aux devices to prevent backpowering
  • Splitting of the I2C Bus between the 3V3 and 3V3 devices
  • The PPC crystal oscillator has been replaced with a clock oscillator
  • Certain ZDOK lines moved to different banks on the FPGA
  • The 6.8mm battery holder has been replaced with a CR2032(20mm) holder
  • An additional PPC LED as well as a redesigned LED layout
  • Redesigned "Power Override" and "AutoStart" circuitry
  • JTAG Isolation


A diagram highlighting the location of some of the major changes on the board can be found at : https://github.com/ska-sa/roach2_hardware/blob/master/release/rev2/A/ASSEMBLY/ROACH%202%20REV%202%20UPDATES.pdf


Mezzanine Cards

ROACH-2 introduces slots for two multi-gigabit transceiver mezzanine cards. This add flexibility to choose whichever 10Ge physical layer is most convenient. It also provides an opportunity to research high-speed ADCs.

Two CX4 mezzanine card placed

A CX4 version of this card has been designed and tested. The card supports three CX4 ports, a fourth set of XAUI signals is taken to two headers. There are an additional 6 x 1.5V CMOS IOs taken to a gpio connector. The CX4 port support active cables. More information is here: CX4 (3 x CX4 Mezzanine board)

A quad SFP+ version is in progress. See SFP+ (Quad SFP+ Mezzanine board).


Production

Prototype run of three boards completed with Digicom in August 2012.

Pre-production run of 7 boards planned for September 2012.

Full production still TBD.

Toolflow

Currently the MMSGE toolflow will only support 11.4-5 ISE/EDK tools. The board support package supports any ISE version beyond 11.4. In the long term we need to get the MSSGE tools working with newer tools.

Documentation

A ROACH-2 datasheet can be found here: https://github.com/ska-sa/roach2_hardware/blob/master/release/rev2/A/ASSEMBLY/ROACH2-REV2%20Datasheet.pdf

Testing/Bringup Status

The boards are currently being tested. Check back soon for further updates.


Updating tcpborphserver 3 etc.

Grab the latest versions from [ https://github.com/ska-sa/roach2_nfs_uboot/ ].

If you netboot: copy tcpborphserver3 to nfs_root_directory/usr/local/sbin. Tcpbporphserver3 will load automatically when the roach boots.

If you soloboot (boot the root file system stored in flash), which is the easiest please follow these instructions:

You need to update to the latest romfs which includes the new tcpborphserver3.

To update:

ROACH2 Test machine set-up instructions: setup instructions (google doc)

  1. Set up a tftp and dhcp server (see the tftp section in the test machine setup instructions).
  2. Create a symlink or rename the romfs image downloaded from github to romfs e.g. "ln -s roach2-root-readdebug-2013-02-12.romfs romfs" in the tftp directory.
  3. Connect to the roach via USB using a terminal emulator: In linux we use minicom, please follow the minicom setup instructions in the document.
  4. Switch the roach on or reset and interrupt the boot process
  5. At the uboot prompt type: run tftproot
  6. This takes a long time! About 5 minutes.
  7. type "reset" and let the board boot linux
  8. Login using root (password is blank)
  9. rm /usr/.keep
  10. reboot -f

If you do not which to run a dhcp and tftp server you can use "run newroot". This macro starts a y-modem receiver, the file can now be sent using minicom via y-modem protocol, but this takes a long time and you really need a dhcp server unless you are going to set the roach ip address manually. You can set the IP address by editing /etc/network/interfaces

To measure temperatures, voltages and currents:

All sensors are available using kcp commands. You can telnet to the board to run kcp commands (telnet board_ip 7147) or if you have access to the console you can run the commands using the program kcpcmd ("kcpcmd sensor-list" note that there is no ?)

?sensor-list - lists all the sensors
?sensor-value - lists all the current values
?sensor-sampling sensor_name event - this will give updates when the sensor changes.

Enclosure

ROACH_2_Enclosure

Usage Manuals, Guides, Memos, etc.

  • ROACH DDR3 Modules.
  • Sync inputs
    • For Roach2 rev1 and Roach2 rev2 there are at least two possible sync inputs:
      • via the vertical mount SMA receptacle connector J10. This signal is terminated into 50 ohms and then turned into the LVDS differential pair "AUX_SYNCI_P" and "AUX_SYNCI_N" via an Analog Devices ADCMP605BCPZ comparator and enters the FPGA at pins BB16 and BB17.
      • via the vertical mount SMA receptacle connector J9. This signal is terminated into 50 ohms and then turned into the LVDS differential pair "AUX_CKL_P" and "AUX_CLK_N" via an Analog Devices ADCMP605BCPZ comparator and enters the FPGA at pins AV16 and AW16. These pins are designated as single region clock capable (SRCC) and thus are apt to be better suited to drive signals with stricter timing requirements (high speed, numerous loads, ...)
      • These pins are in the standard Roach1 design libraries but the updated GPIO block in the ADC16 gateware repository may be required for the Roach2 rev 2.
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